Miller JETLINE 9690_ALC-401 Owner's manual

Jetline Engineering, 15 Goodyear Street, Irvine, CA 92618

Telephone: (949) 951-1515 • Fax: (949) 951-9237

Web Site: www.jetline.com • E-mail: [email protected]

June 2010 - Rev 5

Effective with Serial Number 100014

IMPORTANT

Read this manual carefully before installing,

commissioning or operating this product.

OPERATION MANUAL

for

ALC-401

Arc Length Control

OM-ALC-401-06-2010

ALC-401D Arc Length Control

- ii -

ALC-401D Arc Length Control

- iii -

LIMITED WARRANTY

Jetline Engineering, of Irvine, California, U.S.A., warrants all new equipment to be free from defects

in material and workmanship for the period of one (1) year, provided that the equipment is installed

and operated according to instructions.

Jetline Engineering’s obligation under this warranty is expressly limited to replacing or repairing

any defective part or correcting any manufacturing defect without charge during the warranty period,

if Jetline’s inspection conrms the existence of such defects. Jetline’s option of repair or replacement

will be F.O.B. factory at Irvine, California, and therefore no compensation for transportation costs of

any kind will be allowed.

The warranty period begins on the date of sale to the original-purchase user of the equipment.

Jetline Engineering will not be liable for any loss or consequential damage or expense accruing

directly or indirectly from the use of equipment covered by this warranty.

This warranty supersedes all previous Jetline warranties and is exclusive with no other guaran-

tees or warranties expressed or implied.

ALC-401D Arc Length Control

- iv -

NOTICE

The installation, operation and maintenance guidelines set out in this manual will enable you to

maintain the equipment in peak condition and achieve maximum efciency with your welding opera-

tion. Please read these instructions carefully to become aware of every advantage.

CAUTION

Only experienced personnel familiar with

the operation and safe practice of welding

equipment should install and/or use

this equipment.

ALC-401D Arc Length Control

- v -

Table of Contents

Section I ..........................................................................................................................................1

Safety Precautions ................................................................................................................1

A. Arc Welding ...............................................................................................................1

B. Electric Shock ............................................................................................................1

C. Arc Rays .....................................................................................................................2

D. Fumes and Gases ........................................................................................................2

E. Cylinders ....................................................................................................................2

F. Welding ......................................................................................................................3

G. Moving Parts .............................................................................................................. 3

H. EMF Information .......................................................................................................3

I. Principal Safety Standards .........................................................................................4

Section II ..........................................................................................................................................5

Introduction ..........................................................................................................................5

A. Control, 9690 .............................................................................................................5

B. Actuator, ALC-401-60D ............................................................................................5

C. Actuator Cable, ALC-401-CAB .................................................................................5

Section III ..........................................................................................................................................7

Specications ........................................................................................................................7

A. Actuator ......................................................................................................................7

B. Control .......................................................................................................................8

Section IV ..........................................................................................................................................9

Description ............................................................................................................................9

A. Control .......................................................................................................................9

B. Actuator ....................................................................................................................10

C. Actuator Cable .........................................................................................................10

D. Optional Items ..........................................................................................................10

Section V ........................................................................................................................................11

Installation and Setup ......................................................................................................... 11

A. Lead Sense Polarity .................................................................................................. 11

B. Actuator ....................................................................................................................12

C. Control .....................................................................................................................13

D. Torch ........................................................................................................................13

E. Interconnections ....................................................................................................... 13

F. Ground Rod ..............................................................................................................14

ALC-401D Arc Length Control

- vi -

Section VI ........................................................................................................................................15

Controls ..............................................................................................................................15

Section VI ........................................................................................................................................17

Controls ..............................................................................................................................17

A. Operation Mode .......................................................................................................17

B. Display Screens - Upper Line ..................................................................................17

C. Display Screens - Lower Line ..................................................................................20

D. Display Screens - Right Side Messages ................................................................... 22

E. Setup Mode ..............................................................................................................22

F. Calibration Mode .....................................................................................................23

Section VIII ........................................................................................................................................29

Calibration Procedure .........................................................................................................29

A. Arc Voltage Calibration Check ................................................................................29

B. Touch Up Calibration - Actual Input Numbers ........................................................ 29

C. Remote Set Point Calibration Check - SET VOLTAGE in REMOTE mode ..........30

Section IX ........................................................................................................................................33

Maintenance ........................................................................................................................33

A. ALC-401-60D Actuator ...........................................................................................33

B. 9690 Control ............................................................................................................33

Section X ........................................................................................................................................35

Parts Lists ...........................................................................................................................35

Section XI ........................................................................................................................................47

PCB Descriptions ...............................................................................................................47

A. 9600-10 Micro-controller Board .............................................................................. 47

B. 9690-11 Isolation Board ...........................................................................................51

C. 9690-12 Brake Controller ........................................................................................54

D. 9690-13 PWM Filter Board .....................................................................................54

Section XI ........................................................................................................................................57

PCB Descriptions ...............................................................................................................57

ALC-401 Arc Length Control

- 1 -

Section I

Safety Precautions

CALIFORNIA PROPOSITION 65 WARNING

This product contains chemicals, including lead,

known to the state of California to cause cancer,

and birth defects or other reproductive harm.

Wash hands after use. §248224

A. Arc Welding

Arc Welding can be hazardous. Protect your-

self and others from possible serious injury or

death. Keep children away. Pacemaker wear-

ers keep away until consulting your doctor.

In welding, as in most jobs, exposure to certain

hazards occurs. Welding is safe when precau-

tions are taken. The safety information given

below is only a summary of the more complete

safety information that will be found in the

Safety Standards listed at the end of this section.

Read and follow all Safety Standards.

Have all installation, operation, maintenance

and repair work performed only by qualied

people.

B. Electric Shock

Touching live electrical parts can cause fatal

shocks or severe burns. The electrode and work

circuit is electrically live whenever the output is

on. The input power circuit and machine internal

circuits are also live when power is on. When

using mechanized wire feed, the wire, wire reel,

drive roll housing and all metal parts touching

the welding wire are electrically live. Incorrectly

installed or improperly grounded equipment is

a hazard.

1. Do not touch live electrical parts.

2.

Wear dry, hole-free insulating gloves and

appropriate body protection.

3. Disconnect input power before installing or

servicing this equipment. Lockout/tagout

input power according to OSHA 29 CFR

1910.147 (see Safety Standards).

4. Properly install and ground this equipment

according to the operation manual and

national, state and local codes.

5. Always verify the supply ground-check and

be sure that input power cord ground wire

is properly connected to ground terminal

in disconnect box or that cord plug is con-

nected to a properly grounded receptacle

outlet.

6. When making input connections, attach

proper grounding conductor rst - double-

check connections.

7.

Frequently inspect input power cord for

damage or bare wiring. Replace cord imme-

diately if damaged - bare wiring can kill.

8. Turn off all equipment when not in use.

9.

If earth grounding of the workpiece is required,

ground it directly with a separate cable - do not

use work clamp or work cable.

10. Do not touch electrode if you are in contact

with the work, ground, or another electrode

from a different machine.

11. Use only well-maintained equipment.

Repair or replace damaged parts at once.

Maintain unit according to manual.

12. Wear a safety harness if working above

oor level.

13. Keep all panels and covers securely in

place.

14. Clamp work cable with good metal-to-

metal contact to workpiece or worktable

as near the weld as practical.

WARNING

ALC-401 Arc Length Control

- 2 -

C. Arc Rays

Arc rays can burn eyes and skin; noise can

damage hearing; ying slag or sparks can injure

eyes.

Arc rays from the welding process produce in-

tense visible and invisible (ultraviolet and in-

frared) rays that can burn eyes and skin. Noise

from some processes can damage hearing.

Chipping, grinding and weld cooling throw off

pieces of metal or slag.

1. Use approved ear plugs or ear muffs if

noise level is high.

2. Use a welding helmet tted with a proper

shade of lter to protect your face and

eyes when welding or watching.

3. Wear approved safety glasses with side

shields.

4. Use protective screens or barriers protect

others from ash and glare; warn others

not to watch the arc.

5. Wear protective clothing made from

durable, ame-resistant material (wool

and leather) and foot protection where

necessary.

D. Fumes and Gases

Fumes and gases can be hazardous to your

health.

Welding produces fumes and gases. Breathing

these fumes and gases can be hazardous to your

health.

1. Keep your head out of the fumes. Do not

breathe the fumes.

2. If inside, ventilate the area and/or use

exhaust at the arc to remove welding

fumes and gases.

3. If ventilation is poor, use an approved

air-supplied respirator.

4. Read the Material Safety Data Sheets

(MSDS) and the manufacturer’s instruc-

tion for metals, consumables, coatings,

cleaners, and degreasers.

5. Work in a conned space only if it is well

ventilated, or while wearing an air-sup-

plied respirator. Always have a trained

watch person nearby.

6. Do not weld in locations near degreasing,

cleaning, or spraying operations. The

heat and rays of the arc can react with

vapors to form highly toxic and irritating

gases.

7. Do not weld on coated metals, such as

galvanized, lead or cadmium plated steel,

unless the coating is removed from the

weld area, the area is well ventilated,

and if necessary, while wearing an air-

supplied respirator. The coatings and any

metals containing these elements can give

off toxic fumes if welded.

E. Cylinders

Cylinders can explode if damaged.

Shielding gas cylinders contain gas under high

pressure. If damaged, a cylinder can explode.

Since gas cylinders are normally part of the

welding process, be sure to treat them care-

fully.

1. Protect compressed gas cylinders from

excessive heat, mechanical shocks, slag,

open ames, sparks, and arcs.

2. Install cylinders in an upright position by

securing to a stationary support or cylin-

der rack to prevent falling or tipping.

3. Keep cylinders away from any welding

or other electrical circuits.

4. Never weld on a pressurized cylinder

- explosion will result.

ALC-401 Arc Length Control

- 3 -

5. Use only correct shielding gas cylinders,

regulators, hoses and ttings designed for

the specic application; maintain them

and associated parts in good condition.

6. Turn face away from valve outlet when

opening cylinder valve.

7. Keep protective cap in place over valve

except when cylinder is in use or con-

nected for use.

8. Read and follow instructions on com-

pressed gas cylinders, associated equip-

ment, and CGA publication P-1 listed in

Safety Standards.

F. Welding

Welding can cause re or explosion.

Welding on closed containers, such as tanks,

drums, or pipes, can cause them to blow up.

Sparks can y off from the welding arc. The

ying sparks, hot workpiece, and hot equipment

can cause res and burns. Accidental contact of

electrode to metal objects can cause sparks, ex-

plosion, overheating, or re. Check and be sure

the area is safe before doing any welding.

1. Protect yourself and others from ying

sparks and hot metal.

2. Do not weld where ying sparks can

strike ammable material.

3. Remove all ammables within 35 ft. (10.7

m) of the welding arc. If this is not pos-

sible, tightly cover them with approved

covers.

4. Be alert that welding sparks and hot mate-

rials from welding can easily go through

small cracks and openings to adjacent

areas.

5. Watch for re, and keep a re extin-

guisher nearby.

6. Do not weld on closed containers such

as tanks, drums, or pipes, unless they are

properly prepared according to AWSF4.1

(see safety Standards).

7. Connect work cable to the work as close

to the welding area as practical to prevent

welding current traveling long, possibly

unknown paths and causing electric

shock and re hazards.

8. Wear oil-free protective garments such

as leather gloves, heavy shirt, cufess

trousers, high shoes, and a cap.

G. Moving Parts

Moving parts, such as fans, rotors, and belts can

cut ngers and hands and catch loose clothing.

1. Keep all doors, panels, covers, and guards

closed and securely in place.

2. Have only qualified people remove

guards or covers for maintenance and

troubleshooting as necessary.

H. EMF Information

Considerations About Welding and the Ef-

fects of Low Frequency Electric and Magnetic

Fields

The following is a quotation from the General

Conclusions Section of the U.S. Congress, Of-

fice of Technology Assessment, Biological

Effects of Power Frequency Electric & Mag-

netic Fields - Background Paper, OTA-BP-E-53

(Washington, DC: U.S. Government Printing

Ofce, May 1989):

ALC-401 Arc Length Control

- 4 -

“.... there is now a very large volume of scien-

tic ndings based on experiments at the cel-

lular level and from studies with animals and

people which clearly establish that low fre-

quency magnetic elds can interact with, and

produce changes in, biological systems. While

most of this work is of very high quality, the

results are complex. Current scientic un-

derstanding does not yet allow us to interpret

the evidence in a single coherent framework.

Even more frustrating, it does not yet allow

us to draw denite conclusions abut questions

of possible risk or to offer clear science-based

advice on strategies to minimize or avoid

potential risks.”

To reduce magnetic elds in the work place, use

the following procedures:

1. Keep cables close together by twisting or

taping them.

2. Arrange cables to one side and away from

the operator.

3. Do not coil or drape cables around the

body.

4. Keep welding power source and cables

as far away as practical.

5. Connect work clamp to workpiece as

close to the weld as possible.

About Pacemakers:

The above procedures are among those also

normally recommended for pacemaker wearers.

Consult your doctor for complete information.

I. Principal Safety Standards

Reference as applicable

Safety in Welding and Cutting, ANSI Standard

Z49.1, from American Welding Society, 550

N.W. LeJeune Rd, Miami, FL 33126

Safety and Health Standards, OSHA 29 CFR

1910, from Superintendent of Documents, U.S.

Government Printing Ofce, Washington, D.C.

20402

National Electric Code, NFPA Standard 70 from

National Fire Protection Association, Battery-

march Park, Quincy, MA 02269

Recommended Safe Practices for the Prepara-

tion for Welding and Cutting of Containers That

Have Held Hazardous Substances, American

Welding Society Standard AWS F4.1, from

American Welding Society, 550 N.W. LeJeune

Rd, Miami, FL 33126

Safe Handling of Compressed Gases in Cylin-

ders, CGA Pamphlet P-1, from Compressed Gas

Association, 1235 Jefferson Davis Highway,

Suite 501, Arlington, VA 22202

Code for Safety in Welding and Cutting, CSA

Standard W117.2, from Canadian Standards

Association, Standards Sales, 178 Rexdale Bou-

levard, Rexdale, Ontario, Canada M9W 1R3

Sales Practices for Occupation and Educational

Eye and Face Protection, ANSI Standard Z87.1,

from American National Standards Institute,

1430 Broadway, New York, NY 10018

Cutting and Welding Processes, NFPA Standard

51B, from National Fire Protection Association,

Batterymarch Park, Quincy, MA 02269

ALC-401 Arc Length Control

- 5 -

Section II

Introduction

This detailed technical manual is designed for

use by the operator, supervisor and engineer. It

provides a detailed explanation of the installa-

tion, operation and maintenance of the equip-

ment.

The ALC-401 arc length control system consists

of three elements:

A. Control, 9690

The 9690 microprocessor control brings state

of the art control to the task of maintaining a

consistent arc length in GTAW (TIG) and PAW

(Plasma) welding processes. A simplied front

panel layout provides less confusion for the

operator by avoiding a multitude of switches

and dials. The LCD display guides the user

through set up and maintenance tasks as well as

providing informational messages as the weld

proceeds. The quality design and manufacturing

of the unit, along with its technical simplicity,

will provide many years of trouble-free, depend-

able service.

The control is designed specically to control

the movement of the arc length control actuator,

prior to, during and after welding. Providing

that all the necessary precautions have been

taken with the installation, the control is fully

compatible within the electrical noise environ-

ment encountered during GTAW (TIG) and PAW

(Plasma) welding.

B. Actuator, ALC-401-60D

This new design actuator provides many advan-

tages over previous models. The torch carrying

slide is driven through a ball screw and is guided

on linear guideways. This provides movement

with very low friction resulting in smoother

travel, increased response and larger weight

carrying capacity.

The actuator is enclosed in a steel cover to

provide dependable operation in areas of high

temperature as may be encountered in hard sur-

facing and deep groove applications.

Electronic touch retract is standard on the unit,

this proven method is particularly suitable when

small diameter electrodes are being employed.

The touch retract function can be disabled

through the control for plasma welding appli-

cations.

C. Actuator Cable,

ALC-401-CAB

The control is connected to the actuator by a

cable with Amphenol® connections at both ends.

The standard cable (supplied with a system) is

10 ft (3 m) long. Interconnection cables up to

75 ft (23 m) are acceptable and are available as

optional items. For applications requiring longer

interconnection cables, call Jetline for advice.

ALC-401 Arc Length Control

- 6 -

ALC-401 Arc Length Control

- 7 -

Section III

Specications

A. Actuator

Part # ALC-401-60D

Two actuators are available for the ALC-401D

Arc Length Control system. They differ only

in the length of stroke.

The standard actuator (supplied with a standard

system) has a stroke length of 6” (150 mm).

The alternative unit has a stroke length of 12”

(300 mm).

Drive: Recirculating Ball

Screw

Mechanism: Linear Guideways

Mounting Holes: 2 x 13/32” (10 mm)

diameter

Mounting Positions: Four positions

See drawing

Torch Holder: Universal vee-clamp

type

Torch Diameters: 3/4” to 1½” (19 to 38

mm) Diameters

Weight Capacity: 40 lb (18 kg) at the

centerline of the torch-

holder

Max. Drive Speed: 30 IPM (750 mm/min)

Overall Dimensions

Length: 19” (483 mm)

Width: 5.125” (130 mm)

Depth: 2.8” (71 mm)

Weight: 17 lb (7.7 kg)

7

(178)

19

(482)

2.19 (56)

6 (152)

STROKE

8 (203)

4.25 (108)

4 (102)

4.25 (108)

2.5 (64)

5.125

(130)

ALTERNATE

MOUNTING

POSITIONS

MEASUREMENTS ARE

SHOWN IN INCHES (MM)

4.2

(107)

ALC-401 Arc Length Control

- 8 -

Voltage Range: 5 to 35 DC or AC

Accuracy: +0.1% or 0.1 Volt

(Whichever is the greater)

Starting Arc Gap: 0 to 0.25” (6 mm)

Start Delay Distance: 0 to 99.9 seconds

Processor: Intel® 80C196KC, 20 MHZ.

Display: 2 x 20 Backlit LCD

Panel: Polycarbonate Overlay

Input: 120/240 VAC, 50/60 Hz

Single Phase, 200 VA

Power Cord: 6 ft (1.8 m) long

Control Wgt: 24 lb (11 kg)

B. Control

12 (300)

Dimensions are in

inches (millimeters)

6.25 (159)

8 (200)

CRS

10.25 (260)

4 HOLES

5/16 (8)

ALC-401 Arc Length Control

- 9 -

Section IV

Description

The ALC-401 Arc Length Control system is

designed to maintain a consistent arc length

during the GTAW (TIG) and Plasma (PAW)

welding processes. This is achieved by means

of a closed-loop servo system. The welding

voltage is sensed and sent to the control which

analyzes it, compares it with the reference signal

(the desired arc voltage which has been entered

into the program) and then sends commands to

cause the drive motor to extend or retract the

actuator. The actuator carries the welding torch

whose position relative to the part being welded

is therefore adjusted.

The complete system consists of the following

elements:

• 9690 Control

• ALC-401-60D Actuator, with standard 6”

(150 mm) stroke

• ALC-401-CAB Actuator Cable

Optional items include:

• ALC-CH1A Actuator, with 1” (25 mm)

stroke

• ALC-CH4A Actuator, with 4: (100 mm)

stroke

• ALC-401-60D-12 Actuator, with 12” (300

mm) stroke

• ALC-401-CAB-XX (“XX” represents the

cable length in feet; maximum 75 ft (23 m)

• 9600S-ALC-3 (or S2) Cable to connect to

9600 control; 3 ft (1 m) long

• RP-401 Pendant Control

A. Control

The 9690 control is enclosed in a dust-tight

enclosure with a hinged door. Connections are

made using three Amphenol® connectors:

• S1 Connector — Actuator cable

• S2 Connector — Remote Pendant cable

• S3 Connector — Cable to auxiliary con-

trols

The control is protected by a 3 amp cartridge

fuse, a 10 ft (3 m) power cable is provided. The

control accepts input voltages of 115VAC +10%

or 230VAC +10%.

The control is microprocessor based, this

provides enhanced operation and ease of use.

Instructions are entered and messages are dis-

played on the control’s LCD display. In addition

to the display, the front panel overlay incorpo-

rates touch pads and an encoder knob to select

and enter information.

The control has three modes of operation:

Operator Mode: This is the mode which is

active whenever the unit is switched on. In this

mode, the operator can change the desired arc

voltage as well as being able to set sensitivity

and select manual/auto mode.

Set-up Mode: When this mode is selected, it

is possible for a supervisor to select and adjust

certain parameters, such as jog speeds.

Calibration Mode: This mode is used when-

ever it is necessary to check the unit’s calibration

or to make other signicant changes.

ALC-401 Arc Length Control

- 10 -

B. Actuator

Actuators are available in several stroke

lengths.

• 6” (150 mm), standard

• 12” (300 mm)

• 4” (100 mm), compact

• 1” (25.4 mm), compact

The drive unit consists of a torch slide mecha-

nism which rides on two linear guide rails.

Motion is imparted through a ball screw and nut

driven by a geared DC servo motor. The use of

recirculating ball linear bearings results in ex-

tremely smooth movement with high sensitivity

and responsiveness.

The actuator mechanism is protected by a metal

cover with dust protection for the moving torch

slide. At the end of the torch slide, a torch holder

is provided suitable for the securing of a wide

range of different style torches. A switch is

mounted at the top of the actuator, this permits

the operator to manually jog the torch up or

down prior to welding.

A mounting plate is provided at the rear of the

actuator to secure the unit to the welding xture.

The mounting plate can be repositioned verti-

cally on the actuator. This facility provides a

convenient way of positioning the actuator rela-

tive to the xture and the part to be welded.

Voltage sensing leads are provided, these connect

to a lter circuit within the actuator mechanism.

The purpose of the lter circuit is to protect the

actuator and control from the effects of high

voltage and high frequency signals.

C. Actuator Cable

The standard actuator connection cable is 10 ft (3

m) long and tted with Amphenol® connectors

at both ends. Because of the unique design of

the system, it is possible to situate the control up

to 75 ft (23 m) away from the actuator. Jetline

can provide special length cables. If it is desired

to make these yourself, it will be necessary to

use the following:

Actuator Connector: 3106A-20-33S

Cord Grip: 97-3057-1012-1

Control Connector: 3106A-20-33P

Cord Grip: 97-3057-1012-1

Cable: 18ga, 6 pairs, Shielded

D. Optional Items

Auxiliary Interconnection Cable

ALC-401-CAB95

A cable is available to connect the arc length

control to a Jetline 9500 System Controller. This

cable permits signals to and from the two units

to be exchanged to provide integrated control.

Remote Pendant Control

The RP-401 Pendant Control is designed for

applications where the operator cannot easily

reach the arc length control from the weld point.

The control is complete with a 15 ft (4½ m)

long cable and plug and includes the following

functions:

• Voltage Control (10 turn potentiometer)

• Voltage Sensing Lockout Switch

• Jog Up/Down Switch

ALC-401 Arc Length Control

- 11 -

Section V

Installation and Setup

On receipt of the equipment, carefully check to

ensure that there is no damage caused by ship-

ping or incorrect handling.

Correct installation of the system will ensure

efcient, trouble-free operation. Although the

equipment has been designed and manufactured

to operate within a GTAW (TIG) or Plasma

(PAW) welding environment, it is still very

important to pay attention to its installation,

especially to adequate grounding and intercon-

nection.

The drawing below shows the required intercon-

nection for a typical installation. The equipment

should be installed as follows:

A. Lead Sense Polarity

The ALC-401 sense lead connections should be:

Red sense lead to welding torch, and Black sense

lead connection to Work ground. This connec-

tion conguration should always be maintained

during the normal operation of the ALC unit.

Additionally, the DCEP mode (Reverse Polarity)

should not be selected while the ALC is con-

nected to the system if the welding power source

is capable of DCEN (Electrode Negative), DCEP

(Electrode Positive) and/or AC welding,. The

ALC-401 is designed to work only while the

torch is in a negative polarity condition. If the

ALC is connected to a DCEP system, there will

be two main problem areas:

ALC-401 Arc Length Control

- 12 -

Touch Retract – Because the ALC uses the

“electronic touch retract” method for setting

the starting arc gap, it sends a negative 12 volt

DC signal to the welding torch electrode when

jogging the torch down, then monitors this volt-

age waiting for it to go to near zero volts, as it

will when the electrode contacts the workpiece.

At this point the ALC will stop and retract the

programmed distance, setting the starting arc

gap. If the welding power source is in the EP

mode, the -12vdc signal from the ALC will be

dragged down to near-zero voltage due to the

low impedance of the electrode terminal of the

power supply to a negative voltage, when in EP.

When this happens the ALC will stop and retract

continually (as long as the operator holds the

jog down key in), thinking it has contacted the

work and can not break contact by retracting.

Due to this, the outward appearance will be that

the ALC jogs upward when pressing the Raise

or the Lower keys.

Arc On – Sample and Hold Circuitry – The ALC-

401 controller uses a sample and hold amplier

circuit in the front end of the arc voltage detec-

tion circuit. The ALC-401 will “Sample” when

the arc voltage is negative (EN) and will hold

the sampled value when the arc voltage is posi-

tive (EP). This sample and hold circuit is used

instead of simple rectication, primarily for AC

welding. The ALC will only recognize the EN

portion of the waveform and disregard the EP

portion. During the EP (cleaning) portion, the arc

voltage is typically much higher than the true arc

voltage during the EN (welding) cycle, and is of-

ten unstable. In this way, the ALC uses only the

EN voltage for tracking without averaging the

EP voltage into the measurement circuits. This

generally gives a smoother tracking response if

the AC Balance on the welding power supply is

kept in the 70% to 80% range.

If welding in DC Straight Polarity (DCEN), the

ALC is in the sample mode all of the time and

operates normally. If welding in the AC mode,

the ALC will track only the EN portion of the AC

waveform. If DC Reverse Polarity (DCEP), the

ALC will be in the “Hold” mode all of the time and

will not update any arc voltage measurements. Due

to this, the outward appearance will be that when

the arc strikes in the DCEP mode, the ALC will

not register an “Arc On” signal. This is generally

not viewed to be a problem as automated welding

using arc length control in the DCEP mode is not

recognized as a normal welding process.

B. Actuator

Securely mount the actuator to the welding

xture using the bracket on the rear face of the

actuator. Ensure that the mounting point is rigid

to avoid vibration at the torch when the unit is

operating, especially if it is mounted on a move-

able carriage or similar device. The mounting

bracket has two holes at 7” (178 mm) centers,

use 3/8” (10 mm) screws to secure the actuator.

If the position of the actuator is too high or too

low, the mounting bracket can be repositioned

on the back of the actuator. The normal mount-

ing is with the actuator vertical, however, the

actuator is designed to function satisfactorily

in any orientation.

Torch Holder

Mounting Holes

ALC-401 Arc Length Control

- 13 -

Mount the welding torch in the torch holder

bracket at the lower end of the actuator slide.

The bracket is designed to hold torches with

diameters from 3/4” to 1½” (19 to 38 mm). For

special torches (as may be used for PTA appli-

cations), the torch holder may be removed and

replaced by a special mounting bracket. Use 10

x 24 UNC screws to secure the special bracket to

the torch holder. When using special brackets,

take care not to overload the actuator. Its weight

carrying capacity is a maximum load of 40 lb

(18 kg) with a center of gravity in line with the

centerline of the original torch holder, this is not

more than 1 1/4” (29 mm) from the face of the

torch holder.

C. Control

The control should be mounted on a vertical

surface at a convenient operating position for

the operator and within the recommended cable

length from the actuator. The control has four

mounting holes for 5/16” (8 mm) diameter

screws. Because of the advanced technology

used in the control, there is little heat generated

during the operation of the unit. It is not there-

fore necessary to allow large clearances around

the control for cooling purposes. Some space

should be allowed at the right hand side of the

control, this is where the connections are made

using Amphenol® connectors. If space is at a

premium, right angle connectors are available

from Jetline or your local electrical supplier.

The control is tted with an 6 ft (1.8 m) long

power cord. The cord has an integral 3-pin con-

nector suitable for connection to standard U.S.

110 volt, single phase receptacles. If the unit

is to be used with 220/240 volt, single phase,

it will be necessary to cut off the 110 volt plug

and secure a suitable plug to match the 220/240

volt receptacle in the country in which the unit is

being used. It is now necessary to open the front

panel of the control (this is done by unscrewing

and removing the two 10-32 button head screws

using a 1/8” (3 mm) Allen wrench) in order to

change the voltage input setting. The input volt-

age is changed from 110 to 220 volts by using a

screwdriver and turning the range switch which

is located on the transformer situated in the cen-

ter of the lower part of the control box.

It is important that, in addition to the conven-

tional electrical ground on the mains supply, the

control should be connected to the ground rod.

A connector is provided for this purpose on the

underside of the control cabinet. Use a 12 ga (3

mm2) cable tted with a 1/4” (6 mm) lug at the

control end.

D. Torch

The welding torch should be mounted in the

clamp provided for this purpose on the lower

end of the torch slide on the actuator. The torch

can be mounted at any point along the length of

the barrel, this permits wire guide positioners,

camera and magnetic oscillation mounts to be

accommodated on the barrel below the torch

holder.

E. Interconnections

It is necessary to connect the red sense lead

which exits the top of the actuator to the torch.

Most machine type torches have a connection

for this purpose. This connection can usually

be found at the back end of the torch, inside

the rubber insulator. The brass cable connector

is threaded and a screw provided for the sense

lead connection. If the torch does not have this

connection, connect the red sense lead, either to

the torch connection block (if one is provided),

or to the welding power supply terminal.

The cable provided is 3 ft (1 m) long. If it is nec-

essary to extend this cable, use a well-insulated

splice connection and a suitable length of Bel-

don® #9867 wire. This is a very high voltage

wire, use of an inappropriate wire will lead to

arc starting problems and interference with other

ALC-401 Arc Length Control

- 14 -

equipment in the welding system. Care should

be taken to keep the cable as short as possible

and to avoid routing it close to metal parts of

the xture.

A second wire exits the back of the actuator, this

is the ground lead. It is a 16 ga (1.3 mm2) black

wire which is 25 ft (7½ m) long. This should

be connected to the workpiece ground as close

as possible to the weld point. The wire should

be kept as short as possible because this will

decrease the electrical resistivity and provide

better volt sensing. If it is necessary to extend

this wire, use at least 16 ga (1.3 mm2) wire with

a good splice, 14 ga (2 mm2) will provide lower

resistance if the wire needs to be long.

Do not operate the unit if the red sense and

black ground leads are not connected.

F. Ground Rod

The drawing on page 11 shows the connections

which it is recommended should be made to a

ground rod. The ground rod should be installed

close to the welding xture and should be a 1”

(25 mm) diameter copper or copper-plated bar

which is driven 10 ft (3 m) deep into the ground.

Consult the National Electrical Code or your

local code for acceptable specications. The

use of a ground rod is of particular importance

where HF is used intermittently or continuously

in the GTAW (TIG) welding process.

NOTE

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Miller JETLINE 9690_ALC-401 Owner's manual

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Miller JETLINE 9690_ALC-401 Owner's manual

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