Danfoss AKC 55 System Installation guide

Brand: Danfoss

Model: AKC 55 System

Type: Installation guide

AKCESS System Manual RC.IU.B1.22 4/99.1 6-1

Chapter 6 Configuring and Using Non-AKCESS Nodes

The AKCESS system has the ability to interface with a number of Echelon-equipped non-AKCESS

devices. These are:

EMON energy monitors

Bitzer variable speed compressors

VLT

variable frequency drives for controlling speed of AC motors

Square D electronically controlled lighting panels.

Chapter 6 - 1 Echelon-capable Utility Meters

An AKCESS system can monitor Danfoss-approved energy meters which have an Echelon interface.

Each AKC 55 can monitor up to five meters. Each current source must have a dedicated meter.

Installation After installing the energy meter and current transformers according to instructions provided by their

manufacturer, the meter is connected to the AKCESS I/O network and becomes a node on the network

after configuration. Only one of the meters connected to an AKC 55 can be used for demand limiting.

Configuration To begin configuration of utility meters, select Energy from the main menu, then Utility Meter, then

Configure. You will be asked for the number of utility meters to be configured. After entering a

number, that number of meter names will appear, each with a Setup button. The default names are

“Meter #1,” “Meter #2,” etc. You can change the names as you would any other text field in the AKC

55. When you select the Setup button, then Board & Points, then Locate, the following screen

appears:

You have ninety seconds to press the service pin at the utility meter. The service pin is a small push-

button usually located on the main circuit board of the meter. Consult the meter instructions for its exact

location if it is not immediately apparent. If the meter is located at some distance from the AKC 55 or

PC you are using for configuration, you should arrange to communicate with a colleague stationed at the

meter for this operation.

After the service pin is pressed, you must wait the remainder of the ninety second period before further

action.

Pressing the service pin on the meter causes configuration information to be sent to the AKC 55. The

information received from the utility meter is the number of CT

6 - 2 System Manual RC.IU.B1.22 4/99.1 AKCESS

After you have been notified that a valid service pin message has been received, you should initialize the

utility meter node by selecting its Init field and pressing Enter.

Using Utility Meter

Status Screens To view current energy usage information, select Energy from the main menu, then Utility Meter, and

Meter Status, then select the meter name, and a meter status report appears:

The meter status screen fields show:

(1) the total KWH consumption since initialization (or since last reset via the service screen);

sets, amperage, and voltage. Although you can change these in the Meter Setup screen, the settings

must match the setup in the meter for correct functioning. When a valid service pin message has been

received by the AKC 55, a confirming message box will appear on the screen. If not, an “Operation

Failed” message appears at the bottom of the screen as shown here:

Remember that

when you initialize

the utility meter,

it will be reset.

Any accumulated

data will be lost !

AKCESS System Manual RC.IU.B1.22 4/99.1 6-3

Peak and KWH can be reset from the service screen, which is reached by using the service icon (in the

center) at the bottom of the screen. Both the AKC 55 and the utility meter counters will be reset.

History for

Utility Meters

Setting up and retrieving history for utility meters is much the same as for other datapoints. To configure

history of a meter, from the Main Menu select History, Configure History, and Setup History

Datapoints. This is the screen that appears:

Move the cursor to the fifth icon (a large “O” symbolizing “Other Controllers” and click. When the next

menu appears, select Utility Meter, then select a specific meter:

(2) the current load in KW for the service being metered;

(3) the peak KW since initialization (or since the last reset via the service screen);

(4) the date and time of the last reset for peak;

(5) the date and time of the last KWH reset

[Items 6, 7, and 8 appear ONLY if Demand Limiting has been configured. See the section on demand

limiting for further discussion.]

(6) KW average in window: the average in the demand window. This number is an estimate of the

peak for the window if load conditions continue as they are at present. The average is re-

calculated each minute.

(7) Level: the current demand limiting level. For demand limiting, HVAC units and lighting

zones can be assigned levels from 0 to 11. Loads are shed and restored according to

levels specified during demand limiting configuration. [See the section on demand limiting

for further explanation].

(8) The current load expressed as a percentage of the specified maximum load.

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When you click on a meter, the points available for history are shown:

AKCESS System Manual RC.IU.B1.22 4/99.1 6-5

Retrieving history produces this typical display:

Demand Limiting [When reading this section, it will be useful to review the part of the previous section, “Echelon-capable

Utility Meters, which describes the Meter Status Screen and the meanings of its fields.]

One utility meter per AKC 55 will allow configuration for demand limiting. Configuring demand limiting

strategy is a two-step process. First you select the meter to be used for demand limiting and enter the

parameters; then select the loads to be shed for limiting demand and give each a priority.

In order to use demand limiting, you must have a Danfoss-approved utility meter with Echelon interface

and, if you are going to establish both normal and emergency load limits, you must wire and configure an

on/off input for the automatic transfer switch. In addition, if the site has a coupling switch, you must

wire and configure an on/off input for the coupling switch.

To begin setting up a demand limiting strategy, start at the utility meter configuration screen. From the

main menu, select Energy, then Utility Meter, and Configure; then select the Setup button for the

meter to be used for demand limiting, then select Meter Setup.

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The contents of the demand limiting fields are as follows:

Window size The window width is set to 15, 20, or 30 minutes. Every

minute, the window “slides” forward so that it always contains

the most recent period of time. Each minute the accumulated

KW during that minute is recorded.

Normal load (for each

hour of the day) Enter the upper demand limit you do not wish to exceed for the

given hour of the day under normal operating conditions (when

using normal power).

Moving to the third page of the screen:

AKCESS System Manual RC.IU.B1.22 4/99.1 6-7

Maximum

emergency load Enter the upper demand limit you do not wish to exceed when

the emergency generator is running.

Start shedding at Enter the percent of maximum load at which you want to start

shedding loads.

Start restoring at Enter the percent of maximum load at which you want to start

restoring loads which have been shed.

Enable coupling switch In installations where there are two transformers and/or two

emergency generators, a coupling switch can be used to connect

both loads to one source in case the other source fails.

Number of normal steps The number of steps (levels) which you will allow to be shed

under normal conditions.

Number of emergency

steps The number of steps (levels) which you will allow to be shed

when the emergency generator is running.

Soft start begin level This entry specifies the level down to which loads will be turned

on when the emergency generator starts. A level will be added

each minute unless the specified emergency load for shedding to

start is reached.

The effect of a soft start is to slowly add load to the generator after it starts. If for instance soft start

begin level is set to 6, when the generator starts only refrigeration loads and loads assigned level 7

through 11 will be on. After one minute, if the load is below the “start shedding at” percentage of

maximum emergency load, level 6 will be turned on. After another minute, the same decision will be

made for level 5, and so on down to level one. If at any time the load reaches the “start shedding at”

percentage, load shedding will begin again until the system reaches the “start restoring at” percentage.

Now return to the Energy menu and select Demand Limiting, then Configure. On the Demand

Limiting Menu, there are two items: Select Units (for HVAC) and Select Zones (for lighting). Choose

Select Units and this screen appears:

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Note that the names of the HVAC units appear in the left-most column. If these units had not been

given names during configuration, then “Unit 1,” “Unit 2,” etc. would have appeared. For each HVAC

unit, make the following entries:

Unit The address of the AKC 55 which has the demand meter that

will be used for demand limiting. This can be any AKC 55 in the

network that has a meter configured for demand limiting.

Level The priority for shedding under normal conditions. Levels are

shed in ascending order: level 1, then level 2, and so on up to the

highest level configured, limited by the number of steps allowed.

Levels above the number of steps configured will not be shed

unless the meter configuration is changed. Since there are only

up to ten steps, loads assigned level 11 will never be shed. It is

recommended that loads which are not to be shed are left at level

11, the default value.

Emergency level The priority for shedding when the emergency generator is

running.

If a load is assigned level 0 (zero) for either normal or emergency conditions, the load will never come on

under those conditions.

For lighting zones, the screen entries are the same, except that each relay will have its own level.

How Demand

Limiting Works Utility demand is monitored every minute. Every minute, the most recent n minutes are averaged (where

n is the width of the configured window, 15, 20, or 30 minutes). If the average reaches the configured

“start shedding at” percentage of configured maximum demand, step one (all lighting zones and HVAC

units assigned to level 1) will be turned off. After one minute, when the average is calculated again, if the

demand is still above the configured percentage of configured maximum demand, level two will be shed,

and so on.

When demand has dropped to the “start restoring at” level, the last level shed will be restored, and then

the others in descending order, so that the last load restored will be the one which was shed first.

Restoration will continue as long as the load remains below the “start shedding at” percentage.

AKCESS System Manual RC.IU.B1.22 4/99.1 6-9

As soon as “Bitzer” has been selected as the proof type for the compressor, another question appears:

Reset Bitzer with RO? A yes answer to this question generates a relay output point. If

you wire the relay output point to terminal A7 on the Bitzer

interface board (labeled “Remote Alarm Reset”), you will be able

to use the RO to manually reset the Bitzer compressor if it is in

an alarm shutdown condition.

The next step in configuration is to go to the Rack Configuration screen for Board & Points, then Other

Controllers, and then select Bitzer. The resulting screen has a >Locate< button for each Bitzer

compressor configured.

After you click on a >Locate< button, you have 90 seconds to go to the Bitzer interface module for that

compressor and press the service pin or button. You must press the service button until the service LED

on the module illuminates and remains lit. Communication is established between the Bitzer module and

the AKC 55, which then assigns an address to the module. Note that addresses are reserved as follows:

1-8 for suction group 1, 9-16 for suction group 2, 17-24 for suction group 3, and so on. (Remember that

an AKC 55 can have up to 5 suction groups, and each one can have up to 8 compressors.)

After ninety seconds, if the Bitzer interface module has responded, a new message will display on the

AKC 55 screen, including the Bitzer module’s address.

Chapter 6 - 2 Bitzer Screw Compressor Echelon Interface

An AKC 55 can monitor Bitzer compressors that have an Echelon interface. Since an AKC 55 supports

up to 5 suction groups, each with up to 8 compressors, as many as 40 Bitzer interfaces are possible.

Bitzer Configuration

Configuration of a Bitzer Screw Compressor Interface begins when the Proof type is selected

for the compressor.

6-10 System Manual RC.IU.B1.22 4/99.1 AKCESS

In the example shown, the Bitzer Interface Module has supplied an address of 17, indicating that it is the

first Bitzer compressor in the third suction group configured in this AKC 55.

Compressor Status

and Bitzer Status The compressor status screen for a Bitzer compressor has the same structure and information as the

status screen for any other compressor. But by clicking on the compressor icon, an additional screen

appears, unique to compressors controlled with Bitzer interface modules. The screen looks like this:

AKCESS System Manual RC.IU.B1.22 4/99.1 6-11

The items shown as “Normal” in the screen shown above correspond to the Bitzer alarms discussed

below.

Alarms

Alarms for the Bitzer interface are configured in an AKC 55 by selecting the Bitzer icon from the

Configure Rack Alarms menu. All that is necessary is to set the alarms to the level required (None, Log

only, Normal, or Critical), since the time and level parameters are set by the Bitzer interface. The

alarm configuration screen shows the eight alarms each Bitzer interface can generate:

The meanings of these alarms as given in Bitzer literature are as follows:

Dirty oil filter Not a shut down function. A pressure differential switch built

into the oil filter has detected a 10 psi differential across the

filter.

Motor overload A shut down function. This alarm, which pertains only to semi-

hermetic screw compressors, occurs if compressor motor

windings overheat. A manual reset using the AKC 55’s Bitzer

reset RO is effective if the compressor is manually locked out.

Alternatively, the compressor can be configured to reset

automatically when the motor temperature is again within safe

limits. Consult Bitzer documentation for more information.

Oil flow This alarm condition will result in a shutdown after three

automatic resets. The alarm occurs when an oil flow switch built

into the compressor senses insufficient oil flow, insufficient

differential oil pressure, or both, for more than five seconds. If

the compressor has been configured for manual lockout, it can be

reset using the AKC 55’s Bitzer reset RO. Alternatively, the

compressor can be configured to reset automatically. Consult

Bitzer documentation for more information.

Oil level A shut down function. The oil level in the compressor’s oil

separator is below the safe operating range. Where parallel

compressors with Bitzer control modules are used, all compres-

sors in parallel will be manually locked out. Oil level alarms can

6-12 System Manual RC.IU.B1.22 4/99.1 AKCESS

only be reset automatically by the Bitzer control module after oil

level has returned to the safe operating range. The AKC 55’s

Bitzer reset RO will have no effect on compressors locked

out by oil level alarms.

Discharge temp A shut down function. Discharge temperature has exceeded

212 °F. A manual reset using the AKC 55’s Bitzer reset RO is

effective if the compressor is manually locked out. Alterna-

tively, the compressor can be configured to reset automatically

when the discharge temperature is again within safe limits.

Consult Bitzer documentation for more information.

Phase fail A shut down function. One or more of the three power legs

supplying the compressor has been interrupted, or is connected

improperly. The Bitzer interface will make three attempts to re-

start the compressor at thirty second intervals, then two

additional attempts at five minute intervals before entering a

permanent shutdown condition. The AKC 55’s Bitzer reset

RO will have no effect on compressors locked out by phase

fail alarms.

Rotation fail A shut down function. Compressor rotation has occurred in the

wrong direction. The alarm can be reset using the AKC 55’s

Bitzer reset RO.

Run proof fail A compressor has not responded when being asked to run by the

controller. The alarm can be reset using the AKC 55’s Bitzer

reset RO.

Resetting Shutdowns

with the Bitzer Reset RO

In order to reset a shutdown compressor, manually the Bitzer reset RO must be turned on, then

turned off.

That reset RO has

to be turned on

and off again to

reset a shutdown

Bitzer

compressor !!

AKCESS System Manual RC.IU.B1.22 4/99.1 6-13

Chapter 6 - 3 VLT

Electronic Drive Interface

An AKC 55 can control and monitor Danfoss VLT

electronic drives that have an Echelon interface.

Each AKC 55 can support a maximum of one VLT

per compressor, one per condenser group, and one

per AHU. In the following section, we’ll discuss these applications one by one.

VLT

Configuration

for Compressors

Configuration of a VLT for variable speed compressor control begins when inverter control is selected on

the configuration screen for a compressor. Normally there is only one variable speed compressor in a

suction group, and conventionally it is compressor number one. Here’s the configuration screen for

compressor 1 of a suction group:

For the field Inverter control there are three selections: NONE, VO, and VLT

. After VLT

selected as the type of control, the settings for inverter operation (minimum speed, maximum speed,

etc.) are entered.

VLT

Resets, Proof,

and Faults The example screen shown above contains the default values, which should be changed only by a

knowledgeable technician.

When a VLT

first begins to run (time = r), fault-checking occurs constantly (every 1-3 seconds). If a

fault is detected, the VLT

is reset.

Inverter max resets is the number of resets which can accumulate in the reset counter (a space in the

AKC 55’s memory) before the VLT

is placed in bypass. The reset counter is cleared whenever no

resets have occurred in the past 12 hours. In the case of the unit whose screen is shown above, if the

reset counter = 3, a reset will place the unit into bypass mode.

If at time = (r + proof delay) there is no proof signal, the VLT

is put directly into bypass mode by the

AKC 55 (see below under Inverter Status).

Continuing Configuration Now go to the Configure Rack screen and select Board & Points, then select the far right icon at the

bottom of the screen (a big “O” for “Other”), then select VLT

from the Other Controllers menu.

Once that selection is made, this screen appears:

6-14 System Manual RC.IU.B1.22 4/99.1 AKCESS

Select Locate for the VLT

you are configuring (in this example, the first one listed, which is for compres

sor AA1). Now this screen appears:

You have 30 seconds to press the VLT

service pin. Depending on the distance from the AKC 55 to the

VLT

, you may need to have a colleague standing by at the VLT

and in communication with you for

this procedure.

When the service pin is pressed, if the VLT

is properly connected to the I/O network, after about 90

seconds this message will appear on the AKC 55:

AKCESS System Manual RC.IU.B1.22 4/99.1 6-15

Now the VLT

is completely configured. Simply press any numeral (digit) key as the message says.

Note that it is not necessary to go to rescan the network for new nodes when you configure a device that

has a service pin. The service pin operation serves the same purpose for its node.

VLT

Status Screens

for Compressors Compressors with VLT

variable speed drives have a VLT button on their status screen, which looks like

this:

Inverter Status The number shown in the Inverter field is the percent of whatever maximum motor speed was entered

during configuration. The Inverter field can also have other contents, which are as follows:

Bypass on No Proof: There is no proof signal from the VLT

to the AKC 55, and so

the VLT

has been placed in bypass mode. The compressor is

operating as a fixed speed compressor.

6-16 System Manual RC.IU.B1.22 4/99.1 AKCESS

Off The AKC 55 refrigeration function is not calling for the

compressor to run.

Resetting The VLT

is being reset. This message will appear for a period

of time equal to the reset delay.

Bypass on Fault The VLT

has reported a fault in its operation and has been

placed in bypass mode. The compressor is operating as a fixed

speed compressor.

Bypass on No Proof The AKC 55 is calling for the VLT

to run, but no proof signal is

being received

In the lower left corner of the screen body is a VLT button. Select it, and you will see the VLT

Status screen:

The screen above shows an inverter in normal operation. Field contents and meanings are as follows:

No Fault Normal operation. The drive is not in bypass.

Fault The drive, due to improper operation, has been put into bypass

mode. The compressor will operate at 100% speed whenever it

is turned on by the AKC 55 refrigeration function, which will

not consider the compressor as a variable speed compressor.

No Warning Normal operation.

Warning Warning messages are sent to the AKC 55 from the VLT

; there

are six types of warning, but the type is not sent to the AKC 55

since the warnings are VLT

functions. The type of warning

can only be determined from the display on the VLT

display.

For a full description of VLT

warnings, see the VLT

manual.

Running The inverter proof condition is true. This means that the variable speed compressor is needed

for refrigeration and the AKC 55 senses that the VLT

is sending the compressor current. This

condition can only change if the compressor is taken out of AKC 55 control, at the VLT

keypad if the

drive is changed from Auto to Manual mode (see below), or if the VLT

is in bypass.

AKCESS System Manual RC.IU.B1.22 4/99.1 6-17

Not Running There is no proof. The AKC 55 does not sense that the VLT

sending the compressor current.

Auto The VLT

is being controlled by the AKC 55. This condition

can only be changed at the VLT

keypad.

Manual The VLT

has been taken out of AKC 55 control. This change

can only be made at the VLT

keypad.

VLT

’s and Air-

Cooled Condensers

Configuration Configuration of a VLT

for use with an air-cooled condenser is very similar to the configuration

described above for refrigeration compressors. In the first page of the Configure Rack Condensers

screen, Control method must be set to Target. In the second page of the samescreen, set Fan Inverter

Control to VLT. Then variable speed settings are entered as for refrigeration compressors.

Bypass on Pressure In addition to other error messages described in the section on use of VLT

’s with refrigeration compres-

sors, VLT

’s used with air-cooled condensers have another bypass message, which is Bypass on

Pressure. The maximum head pressure specified in configuration has been reached, and the VLT

has

been placed in bypass. All condenser fans will run continuously to reduce the head pressure.

VLT

’s and Air

Handler Motors

Configuration A VLT

can be used to control the speed of air handler fans wherever RTC rooftop controller boards are

not being used. It is first necessary, during configuration, to select Variable VLT as the fan type.

Maximum and minimum fan speeds and inverter settings are similar to those described above for other

loads. The last two settings on this screen determine the leaving air temperatures at which fan speed is

increased for cooling and for dehumidification. Leaving air temperature is measured by sensors placed on

the cooling coils. Normally the ramp up temperature for dehumidification is lower so that when

dehumidification is needed, the fan will run slower (will not be speeded up until the temperature is

lower) so that the air stream will pass more slowly over the coils and more moisture will be removed.

6-18 System Manual RC.IU.B1.22 4/99.1 AKCESS

Now click on >Setup< to begin Powerlink

configuration.

Chapter 6 - 4 Square D Powerlink

Circuit Breaker Panels

An AKC 55 can control and monitor Square D Powerlink

circuit breaker panels that have an Echelon

interface. Each AKC 55 can support a maximum of five Powerlink

panels. Each Powerlink

panel can

have up to 42 breakers, each of which is considered equivalent to one lighting zone relay.

Powerlink

Configuration

Configuration of a Powerlink

begins after you have entered a number other that 0 in answering the

question “No. of Powerlink Panels?” on the Configure Lighting Zones screen:

AKCESS System Manual RC.IU.B1.22 4/99.1 6-19

The zone name can be changed to any of a list of 33 common lighting zones, or to a user defined name

(the second line on the screen shown above only appears if “User Def.” is selected on the first line.

The number of control points is analogous to the number of relays given for conventional lighting

points. It is the number of controllable groups into which the lights with this name are divided.

Configure each lighting point in turn by starting at the Configure Lighting Zones menu, choosing the type

of control (either PWRLK or AKC 55), then going to >Setup<.

Now go to the Configure Lighting menu and click on Board & Points. Using the icon menu at the

bottom of the screen, click on the right-most icon which resembles a Square D logo. The screen that

appears looks like this:

The panel names (shown by default as “Powerlink #1, Powerlink #2, etc.”) can be edited to match the

names of the actual panels in the store.

Continuing Configuration

Select Locate for the Powerlink

you are configuring (for example, the first one listed). Now this screen

appears:

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Now the Powerlink

location is complete. Simply press any numeral (digit) key as the message says.

Note that it is not necessary to rescan the network for new nodes when you configure a device that has a

service pin. The service pin operation serves the same purpose for its node.

You have 30 seconds to press the Powerlink

service pin. Depending on the distance from the AKC 55

to the Powerlink

, you may need to have a colleague standing by at the Powerlink

and in communica-

tion with you for this procedure. Consult the Powerlink

literature to locate the service pin.

When the service pin is pressed, if the Powerlink

panel is properly connected to the I/O network, after

about 90 seconds this message will appear on the AKC 55:

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Danfoss AKC 55 System Installation guide

Danfoss AKC 55 System Installation guide

Danfoss AKC 55 System Installation guide

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