Satec PM170 User manual

Brand: Satec

Model: PM170

Type: User manual

Series PM170

Powermeters

Communications

Manual

LIMITED WARRANTY

The manufacturer offers the customer an 24-month

functional warranty on the instrument for faulty

workmanship or parts from date of dispatch from the

distributor. In all cases, this warranty is good for 36

months from the date of production. This warranty is on a

return to factory basis.

The manufacturer does not accept liability for any damage

caused by instrument malfunction. The manufacturer

accepts no responsibility for the suitability of the

instrument to the application for which it was purchased.

Failure to install, set up or operate the instrument

according to the instructions herein may void the warranty.

Your instrument should only be opened by a duly

authorized representative of the manufacturer. The unit

should only be opened in a fully anti-static environment.

Failure to do so may damage the electronics and will void

the warranty.

NOTE

The greatest care has been taken to manufacture and

calibrate your instrument. However, these instructions do

not purport to cover all possible contingencies that may

arise during installation, operation or maintenance, and all

details and variations of this equipment do not purport to

be covered by these instructions.

For additional information regarding installation, operation

or maintenance of this instrument, contact the

manufacturer or your local representative or distributor.

BG0045 REV. F

Table of Contents

CHAPTER 1 INTRODUCTION.................................................... 1

1.1 USING THE COMMUNICATIONS PORT.......................................... 1

1.2 EIA INTERFACE STANDARDS ..................................................... 2

1.2.1 EIA RS-232 Standard......................................................... 2

1.2.2 EIA RS-422 and EIA RS-485 Standards ............................ 2

1.3 RESPONSE TIME ......................................................................... 2

1.4 SETUP PARAMETERS .................................................................. 3

1.4.1 Handshaking ...................................................................... 3

CHAPTER 2 PRINT MODE.......................................................... 5

2.1 CONFIGURING THE PRINT MODE PARAMETERS .......................... 5

2.2 CABLE CONNECTIONS ................................................................ 5

2.3 FLOW CONTROL ......................................................................... 5

2.4 PRINTOUT FORMAT .................................................................... 6

CHAPTER 3 ASCII COMMUNICATIONS PROTOCOL......... 8

3.1 ASCII FRAMING ....................................................................... 8

3.2 EXCEPTION RESPONSES.............................................................. 9

3.3 ASCII MESSAGE DESCRIPTION ................................................ 10

3.3.1 Read Data Registers ........................................................ 10

3.3.2 Read Basic Setup.............................................................. 12

3.3.3 Write Basic Setup............................................................. 14

3.3.4 Reset/Clear Functions...................................................... 14

3.3.5 Reset Powermeter ............................................................ 15

3.3.6 Read Firmware Version Number ..................................... 15

3.3.7 Read Real Time Clock...................................................... 16

3.3.8 Write Real Time Clock ..................................................... 16

CHAPTER 4 MODBUS COMMUNICATIONS PROTOCOL . 17

4.1 MODBUS FRAMING................................................................ 17

4.1.1 Transmission Mode.......................................................... 17

4.1.2 The RTU Frame Format .................................................. 18

4.1.3 Address Field ................................................................... 18

4.1.4 Function Field.................................................................. 18

4.1.5 Data Field ........................................................................ 19

4.1.6 Error Check Field ............................................................ 19

4.1.7 Data Conversion .............................................................. 21

4.1.8 Data Addressing Modes................................................... 23

4.2 MODBUS MESSAGE FORMATS ............................................... 24

4.2.1 Function 03 - Read Multiple Registers ............................ 24

4.2.2 Function 04 - Read Multiple Registers ............................ 24

4.2.3 Function 20 - Read Multiple Registers ............................ 25

4.2.4 Function 06 - Write Single Register................................. 26

4.2.5 Function 16 - Write Multiple Registers............................ 27

4.2.6 Function 21 - Write Multiple Registers............................ 27

4.2.7 Function 08 - Loopback Communications Test ............... 28

4.3 EXCEPTION RESPONSES ............................................................ 29

4.4 POWERMETER REGISTERS ........................................................ 29

4.4.1 Data Registers.................................................................. 29

4.4.2 Basic Setup Registers ....................................................... 32

4.4.3 Real Time Clock Registers ............................................... 35

CHAPTER 5 DNP V3.00 COMMUNICATIONS PROTOCOL36

5.1 DNP PROTOCOL....................................................................... 36

5.1.1 Introduction...................................................................... 36

5.1.2 PM170 Deviation from Standard..................................... 36

5.1.3 DNP Request/Response Overview.................................... 37

5.2 DNP INTERFACE ...................................................................... 37

5.2.1 General ............................................................................ 37

5.2.2 DNP Address.................................................................... 38

5.2.3 Transaction Timing .......................................................... 38

5.2.4 Object Format.................................................................. 39

5.3 SERIES PM170 REGISTERS ....................................................... 39

5.3.1 Data Registers.................................................................. 39

5.3.2 Basic Setup Registers ....................................................... 42

5.3.3 Resetting Energy and Demands ....................................... 43

APPENDIX A DNP APPLICATION MESSAGES .................... 44

APPENDIX B DNP DEVICE PROFILE...................................... 46

INDEX .............................................................................................. 51

WARNING

Ensure that all incoming AC power and other power sources are

turned OFF before performing any work on the instrument. Failure

to do so may result in serious or even fatal injury and/or

equipment damage.

This manual is intended for users of communications protocols with the Series

PM170 Powermeters. For installation and setup instructions refer to the Series

PM170 Powermeters Installation and Operation Manual.

For the safety of personnel and equipment, it is essential to read

this manual prior to using the equipment.

Chapter 1 Introduction 1

Chapter 1 Introduction

1.1 Using the Communications Port

The Series PM170 communications port supports EIA RS-

232, RS-422 and RS-485 standard interfaces allowing

connection to a computer, PLC or a printer. The

communications port can operate at baud rates up to 9,600

bps. Various communications options may be selected by the

user via the front panel.

The communications port can operate in one of two modes:

• computer mode, where a host computer polls the

instrument in order to receive data, or to read or

program the Powermeter setup parameters

• print mode, where output is provided in printable

format.

In the computer mode, the instrument uses a two-way

communications protocol. The communications works on a

master-slave basis where the Powermeter is the slave, i.e. it

responds to host computer requests, but does not transmit

information on its own initiative.

The instrument can support two communications protocols:

(1) the domain ASCII, and (2) Modicon's Modbus RTU

(standard) or DNP V3.00 (option). Each of these protocols

can be used by a third-party host-based software to access all

data and configuration registers of the Powermeter. Chapters

3, 4 and 5 provide the complete information necessary to

develop a third-party communications software capable to

communicate with Series PM170 Powermeters. With the

ASCII protocol, the Powermeter is capable of connection to

a master computer via a modem.

In print mode, the Powermeter can be connected to a serial

printer to output a fixed format printed report at user-defined

intervals.

2 Chapter 1 Introduction

1.2 EIA Interface Standards

1.2.1 EIA RS-232 Standard

RS-232 is a serial interface standard that may be used for

single connections (one computer serial port connected to

one instrument), at distances up to 15 meters. It may be

possible to extend this range using lower transmission rates,

shielded cabling, or repeaters. This standard is generally

used when connecting one instrument to a printer. Print

mode is available only with EIA RS-232.

1.2.2 EIA RS-422 and EIA RS-485 Standards

Both RS-422 and RS-485 are serial differential interface

standards, permitting reliable communications for distances

up to 1200 meters. Due to the differential mode used, line

noise is nullified.

In the RS-422 standard, the interconnection of instruments

with a computer is performed via two pairs of lines, one pair

for transmission, and one for reception (full duplex). In the

RS-485 standard, instruments are connected to a computer

via a pair of lines. The same pair is used both for

transmission and reception (half duplex).

1.3 Response Time

The minimum response time of the Powermeter (to allow the

master PC to switch a communications port) is at least 1.75

character time, depending on the baud rate used.

The maximum response time depends on the

communications protocol. In ASCII protocol, the

Powermeter response time will not exceed 80 ms plus 1.75

character time. For the Modbus RTU protocol, the maximum

response time is 80 ms plus 3.50 character time.

Chapter 1 Introduction 3

1.4 Setup Parameters

The Powermeter communications port must be configured

before connecting it to a master computer or printer. The

port and computer/printer configurations must match. Setup

instructions are found in the Series PM170 Powermeters

Installation and Operation Manual.

1.4.1 Handshaking

This optional flow control parameter is used to define the

flow control protocol that may be necessary to adjust

transmission rate of the Powermeter to the needs of a master

computer or a printer. If you do not need to use this

parameter, you can leave it on its default setting.

It may be necessary to compensate for the Powermeter's

ability to send characters faster than they can be accepted by

a modem or printed on a serial printer, when the incoming

data buffer is too small. The Powermeter allows hardware

and software handshaking.

Hardware handshaking is applicable only in RS-232

communications mode. You can use it to provide DTR/DSR

or RTS/CTS flow control protocol by connecting the DTR

and RTS/CTS lines to the appropriate pins on the

communication connector of the computer or printer.

When hardware handshaking is selected, the Powermeter

will not send characters to the communications port until the

DSR/CTS signal is asserted high. If the DSR/CTS is

dropped during transmission, the Powermeter suspends data

transmission until the DSR/CTS is restored.

When hardware handshaking is selected, the DTR signal is

permanently asserted high. This outgoing signal may be

necessary with certain modems, serial printers or signal

converters.

Software handshaking is applicable only in ASCII RS-232

and RS-422 full-duplex communications modes. When a

physical connection between the Powermeter and a master

4 Chapter 1 Introduction

computer or a printer is impossible or where hardware flow

control is not supported, software handshaking can be used

instead. Software handshaking supports the character flow

control protocol known as XON/XOFF. The master should

send an XOFF character (ASCII DC3) when it wishes the

Powermeter to pause in sending data, and an XON character

(ASCII DC1) when it wishes the Powermeter to resume

transmission.

NOTES

In RS-485 half-duplex communications mode, neither

hardware nor software handshaking are applicable.

If you do not need full-duplex mode, you can use the RS-

485 standard in both 4-wire and 2-wire connections (see

Communications Cable Connections, Series PM170

Powermeters Installation and Operation Manual).

Chapter 2 Print Mode 5

Chapter 2 Print Mode

2.1 Configuring the Print Mode

Parameters

When a serial printer is connected to the Powermeter, you

should configure communications mode to Prnt/232, and

select the appropriate printout period. Baud rate and data

format should be configured in the Powermeter as those on

the printer. See the Series PM170 Powermeters Installation

and Operation Manual for instructions on configuration of

the Powermeter communications parameters.

2.2 Cable Connections

Cable connections to the printer may depend on the printer

connector type. Most serial printers have a DTE 25-pin male

connector, but some may have a DCE 25-pin female

connector. Refer to the Series PM170 Powermeters

Installation and Operation Manual for cable drawings of

both connector types.

2.3 Flow Control

Most printers provide a few bytes of buffer storage where

characters can wait their turn to be printed. If the buffer size

is sufficient to accept a full print report, i.e., when a printer

has at least 256 bytes of input buffer, flow control is not

needed. If the buffer size is less than 256 bytes, you should

provide hardware handshaking, otherwise the printer output

will become garbled. Use the DSR/CTS signal to provide

hardware flow control. In the Powermeter, configure the

handshaking mode to HArd .

With a serial-to-parallel converter, you can use a parallel

printer as well. When a converter is used, hardware

handshaking is required. For setup instructions and cable

6 Chapter 2 Print Mode

drawings, refer to the Series PM170 Powermeters

Installation and Operation Manual.

2.4 Printout Format

The instrument sends a fixed format printed report at

user-defined intervals. After power up or completing the

current page, the value heading is printed on the top of the

new page. The printing page height is 62 rows. Each row is

terminated by ASCII characters CR (ASCII 13) and LF

(ASCII 10). On each page, along with a header, 20 readings

are printed. The following illustrations show the printout

formats for the Series PM170 models:

PM170

1 2 3 4 5 6 7 8 9

chars

FREQ

chars

10 11 12

A_MD1

chars

A_MD2

chars

A_MD3

chars

PM170E

1 2 3 4 5 6 7 8 9

chars

FREQ

chars

10 11 12 13 14 15 16

KWH

chars

KVAR

chars

KVARH

chars

A_MD1

chars

A_MD2

chars

A_MD3

chars

MAX_DM

chars

PM170M

1 2 3 4 5 6 7 8 9 10

chars

KVA

chars

KVAR

chars

10 11 12 13 14 15 16 16

KVAH

chars

KWH

chars

KVARH

chars

A_MD1

chars

A_MD2

chars

A_MD3

chars

KVA_MD

chars

KW_MD

chars

I_UB

chars

FREQ

chars

Chapter 2 Print Mode 7

Table 2-1 lists all measured items presented in the print

report with their respective labels and resolution.

Table 2-1 Print Parameters

Parameter

label

Description Resolution

(no.digits)

V1, V2, V3 Voltage per phase L1/L12,

L2/L23, L3/L31

A1, A2, A3 Current per phase L1, L2, L3 5

A_MD

1,2,3

Maximum ampere demand per

phase L1, L2, L3

I_UB Unbalanced current 5

PF Total power factor 4

FREQ Frequency 4

KVA kVA total 6

KW kW total 6

KVAR kvar total 6

MAX_DM Maximum kW demand 6

KW_MD Maximum kW demand 6

KVA_MD Maximum kVA demand 6

KVAH kVAh 6

KWH kWh net 6

KVARH kvarh net 6

8 Chapter 3 ASCII Communications Protocol

Chapter 3 ASCII

Communications Protocol

This chapter explains how data is transferred between a

master computer station and the Powermeter when the

ASCII serial communications protocol is used.

All messages within the ASCII communications protocol are

designed to consist only of printable characters.

3.1 ASCII Framing

The following specifies the ASCII message frame:

Sync

Message

length

Slave

address

Message

type

Message

body

Check

sum

Trailer

SYNC - synchronization character: one character '!' (ASCII

33) used for starting synchronization.

Message length - length of the message including only

the number of bytes in fields #2, #3, #4 and #5. Contains

three characters between '006' and '252'.

Slave address - two characters between '00' and '99'. The

Powermeter with address '00' responds to requests with any

incoming address. For RS-422/RS-485 communications

(multidrop mode), this field must NEVER be zero.

Message type - one character representing the type of a

host request. A list of the message types is shown in Table 3-

Message body - contains the message parameters in

ASCII representation. All parameter fields have a fixed

format. The data fields vary in length depending on the data

type. If not indicated otherwise, the parameters should be

right justified and left-padded with zeros.

Chapter 3 ASCII Communications Protocol 9

The parameters are transferred in a decimal notation ‘as is’,

i.e., no conversion is needed. When a value is between 0 and

1, a decimal point must be placed in the data field. When the

value range exceeds the field range, it is divided by 1000

and truncated to the right. A decimal point is placed after the

thousands to denote that the value has been truncated and

must be multiplied by 1000 before processing.

Check sum - arithmetic sum, calculated in 2-byte words

over fields #2, #3, #4 and #5 to produce a one-byte check

sum in the range of 22h to 7Eh (hexadecimal) as follows:

[Σ(each byte - 22H)] mod 5CH + 22H

Trailer - two ASCII characters, CR (ASCII 13) and LF

(ASCII 10).

NOTE

Fields #3 and #4 of the Powermeter response are always

the same as those in the host request.

Table 3-1 ASCII Message Types

Message type Description

Char ASCII Hex

0 30h Read data registers

1 31h Read basic setup

2 32h Write basic setup

4 34h Reset/clear function

8 38h Program reset

9 39h Read version number

3.2 Exception Responses

The instrument will send the following error codes in the

message body field in response to incorrect host requests:

XK -

Powermeter is in programming mode

XP - invalid setup value or setup is not available

XM - invalid request type

NOTE

When check or framing error is detected, the Powermeter

will not act on or respond to the master's request.

10 Chapter 3 ASCII Communications Protocol

3.3 ASCII Message Description

3.3.1 Read Data Registers

This request is used to retrieve a predefined set of the data

measured by the Powermeter. All electrical parameters are

averaged values over the specified number of the real-time

measurements (see the averaging buffer size in Table 3-5).

Host request:

Message type - '0'.

Message body - none.

Response:

Message type - '0'.

Message body - see Table 3-2.

The message body length: PM170/170E - 163 characters

PM170M - 225 characters

Table 3-2 Response '0' body

No. Offset

(bytes)

Length

(bytes)

Description Unit Range e

1 0 4 Voltage L1/L12 V/kV c 0 to Vmax

2 4 4 Voltage L2/L21 V/kV c 0 to Vmax

3 8 4 Voltage L3/L31 V/kV c 0 to Vmax

4 12 5 Current L1 A 0 to Imax

5 17 5 Current L2 A 0 to Imax

6 22 5 Current L3 A 0 to Imax

7 f 27 6 kW L1 kW/MW c -Pmax to Pmax

8 f 33 6 kW L2 kW/MW c -Pmax to Pmax

9 f 39 6 kW L3 kW/MW c -Pmax to Pmax

10f 45 4 Power factor L1 -.99 to 1.00 d

11f 49 4 Power factor L2 -.99 to 1.00 d

12f 53 4 Power factor L3 -.99 to 1.00 d

13 57 6 kW total kW/MW c -Pmax to Pmax

14 63 4 Power factor total -.99 to 1.00 d

15f 67 6 kWh net kWh/MWh c -999.9 to 9999.9

16g 73 5 Unbalanced current A 0 to Imax

Chapter 3 ASCII Communications Protocol 11

No. Offset

(bytes)

Length

(bytes)

Description Unit Range e

17 78 4 Frequency Hz 45.0 to 65.0

18g82 6 kvar L1 kvar/Mvarc -Pmax to Pmax

19g88 6 kvar L2 kvar/Mvarc -Pmax to Pmax

20g94 6 kvar L3 kvar/Mvarc -Pmax to Pmax

21g100 6 kVA L1 kVA/MVA c 0 to Pmax

22g106 6 kVA L2 kVA/MVA c 0 to Pmax

23g112 6 kVA L3 kVA/MVA c 0 to Pmax

24f118 6 kvarh net kvarh/Mvarh

-999.9 to 9999.9

25f124 6 kvar total kvar/Mvar c -Pmax to Pmax

26g130 6 kVA total kVA/MVA c 0 to Pmax

27f136 6 Maximum kW

demand

kW/MW c 0 to Pmax

28f142 6 Accumulated kW

demand

kW/MW c 0 to Pmax

29 148 5 Maximum ampere

demand L1

A 0 to Imax

30 153 5 Maximum ampere

demand L2

A 0 to Imax

31 158 5 Maximum ampere

demand L3

A 0 to Imax

32g163 2 N/A

33g165 6 Maximum kVA

demand

kVA/MVA c 0 to Pmax

34g171 6 Accumulated kVA

demand

kVA/MVA c 0 to Pmax

35g177 4 N/A

36g181 4 N/A

37g185 4 N/A

38g189 4 N/A

39g193 4 N/A

40g197 4 N/A

41g201 8 kVAh kVAh 0 to 9999999

42g209 6 kW demand kW/MW c 0 to Pmax

43g215 6 kVA demand kVA/MVA c 0 to Pmax

44g221 4 Power factor at

maximum kVA

demand

-.99 to 1.00 d

12 Chapter 3 ASCII Communications Protocol

Fields indicated by an N/A mark are padded with ASCII

zeros.

c When the value width is over the field resolution, the reading is

converted to higher units and transmitted with a decimal point.

The right most digits of the reading are truncated.

d For negative power factor, the minus sign is transmitted before a

decimal point as shown in the table.

e The parameter limits are as follows:

Vmax = 660 [V] if PT Ratio = 1.0 and Vmax = 144*PT Ratio [V] if

PT ratio > 1.0, for the instruments with 660 V input option

Vmax = 144*PT Ratio [V], for the instruments with 120 V input

option

Imax = 1.2 * CT primary current [A]

Pmax = (Imax * Vmax * 3)/1000 [kW] if wiring mode is 4L-N

Pmax = (Imax * Vmax * 2)/1000 [kW] if wiring mode is 4L-L, 3-OP,

or 3DIR

f These parameters are actual for the PM170E/170M only. In the

PM170 response, they are passed as zeros.

g These parameters are present in the PM170M response only.

NOTES

The voltage parameters throughout the protocol can

represent line-to-neutral or line-to-line voltages depending

on the wiring mode selected in the Powermeter. When a 4L-

N wiring mode is selected, they will be line-to-neutral

voltages, and when another mode is selected, they will be

line-to-line voltages.

In 3-wire connection schemes, unbalanced current and the

phase readings for power factor, active power, and reactive

power will be zeros, because they have no meaning. Only

the total three-phase power values can be used.

3.3.2 Read Basic Setup

This request is used to retrieve the current basic setup

parameters.

Host request:

Message type - '1'.

Message body - see Table 3-3.

Chapter 3 ASCII Communications Protocol 13

Table 3-3 Request '1' body

Field

number

Offset

(bytes)

Length

(bytes)

Description

1 0 3 Parameter identifier (see Table 3-5)

Response:

Message type - '1'.

Message body - see Table 3-4.

Table 3-4 Response '1' body

Field

number

Offset

(bytes)

Length

(bytes)

Description

1 0 3 Parameter identifier (see Table 3-5)

2 3 4 Not used (permanently set to 00.0)

3 7 6 Parameter value (see Table 3-5)

Table 3-5 Basic Setup Parameters

Parameter Identifier Unit Parameter Range

Wiring mode

W40 0 = 3OP, 1 = 4L-N,

2 = 3DIR, 3 = 4L-L

PT ratio U14 1.0 to 6500.0

CT primary

current

I17 A 1 to 50000

Power demand

period

D11 min 1,2,5,10,15,20,30,60 min

255 = external synchronization

Ampere demand

period

C12 sec 0 to 1800

0 = measuring peak currents

Averaging buffer

size

S41 8, 32

Reset

enable/disable

R42 0 = disable, 1 = enable

14 Chapter 3 ASCII Communications Protocol

3.3.3 Write Basic Setup

This request allows you to change any basic setup

parameter.

Host request:

Message type - '2'.

Message body - see Table 3-6.

Table 3-6 Request '2' body

Field

number

Offset

(bytes)

Length

(bytes)

Description

1 0 3 Parameter identifier (see Table 3-5)

2 3 4 Not used (set to 00.0)

3 7 6 Parameter value (see Table 3-5)

Response:

Message type - '2'

Message body - see Table 3-6.

3.3.4 Reset/Clear Functions

This request is used to clear accumulated values stored by

the Powermeter.

Host request:

Message type - '4'

Message body - see Table 3-7.

Table 3-7 Request '4' body

Field

number

Offset

(bytes)

Length

(bytes)

Description Range

1 0 1 Reset function see Table 5-8

Chapter 3 ASCII Communications Protocol 15

Table 3-8 Reset/Clear Functions

Function Description

1 Clear energy registers

2 Clear maximum demand registers

Response:

Message type - '4'

Message body - the same as that for the host request.

3.3.5 Reset Powermeter

This request causes the Powermeter to perform full reset and

restart, such as in the event of power up.

Host request:

Message type - '8'.

Message body - none.

Response: None

3.3.6 Read Firmware Version Number

This request is used to retrieve the version of the firmware

installed in the Powermeter.

Host request:

Message type - '9'.

Message body - none.

Response:

Message type - '9'.

Message body - see Table 3-9.

Table 3-9 Response '9' body

Field

number

Offset

(bytes)

Length

(bytes)

Description

1 0 3 Firmware version number

16 Chapter 3 ASCII Communications Protocol

3.3.7 Read Real Time Clock

This request allows the user to obtain the present RTC

indication.

Host request:

Message type - 'S'.

Message body - none.

Response:

Message type - 'S'.

Message body - see Table 3-10.

Table 3-10 Response 'S' body

Field

number

Offset

(bytes)

Length

(bytes)

Description Range

1 0 2 Second 0-59

2 2 2 Minute 0-59

3 4 2 Hour 0-23

4 6 2 Day 1-31

5 8 2 Month 1-12

6 10 2 Year 0-99

3.3.8 Write Real Time Clock

This request allows the user to set up the Powermeter RTC.

Host request:

Message type - 'T'.

Message body - see Table 3-11.

Table 3-11 Request 'T' body

Field

number

Offset

(bytes)

Length

(bytes)

Description Range

1 0 2 Second 0-59

2 2 2 Minute 0-59

3 4 2 Hour 0-23

4 6 2 Day 1-31

5 8 2 Month 1-12

6 10 2 Year 0-99

Response:

Message type - 'T'.

Message body - the same as that for the host request.

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Satec PM170 User manual

Satec PM170 User manual

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