Emerson OpenComms-485 User Manual

MONITORING

OpenComms - 485

Modbus Reference Guide

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Liebert Monitoring Group –Development

Revision Level Updates:

Revision Date Description

1 11/30/04 Initial Revision
2 04/10/06 Added Liebert DS Modbus Registers
3 09/15/06 Updated DS Registers with additional BMS Fan Control data
4 12/06/06 Update S300/S600 register map
5 7/6/2007 Document Holding/Input Register, Status and Coil

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TABLE OF CONTENTS

Modbus Communications..................................................4

Liebert Nfinity......................................................................4

Liebert Nx.............................................................................4

Liebert PowerSure Interactive ...........................................4

Liebert PowerSure Interactive 2 ........................................4

Liebert GXT2........................................................................4

Liebert HiNet........................................................................4

Liebert UPS Series 600.......................................................4

Liebert UPS Series 300.......................................................4

Liebert DS............................................................................4

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Modbus Communications

Connectivity to OpenComms-485 using Modbus

This design specification describes the Modbus communications protocol as
supported by the OC-485 interface card. It includes information on how to pass
information to and from the OC-485 card via Modbus. It is also intended to help
facilitate answering questions regarding supported types, frame format, function
code support etc.

Implementation Basics

Protocol controls the language structure or message format between devices in
other words, the rules for communication. The rules for communication include
how master and slave devices initiate communications, as well as unit
identification, message handling and error checking. Modbus protocol simply
refers to the control of the query and response cycles between master and slave
devices.
The OC-485 card is configured to act as a slave device on a common network.
This common network can be a multi-drop configuration over EIA-485, where
multiple slaves reside on a common wire or loop.

Transmission Format

The OC-485 interface card supports Modbus RTU (Remote Terminal Unit)
transmission modes. . See chart below.

Physical

Port

EIA-

485/422

2 wire

Transmission

Mode

RTU 9600, 19200

Baud Rate Data Bits Parity Bits Stop Bits Default

or 38400

Configurable Configurable Configurable No

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Modbus Packet Format

Each Modbus packet consists of the following fields:

• Device Address

• Function Code

• Data Field(s)

• Error Check Field

Device Address:

The address field immediately follows the beginning of the frame and consists of
8-bits (RTU). This bit indicates the user assigned address of the slave device
that is to receive the message sent by the attached master device.

Each slave must be assigned a unique address and only the addressed slave will
respond to a query that contains its address.

Function Code:

The function code field tells the addressed slaves what function to perform.
Function codes are specifically designed invoke a specific action by the slave
device. The function code range is from 1 to 127.

OC-485 Modbus server supports the following Modbus function codes.
Code Function Description
01 Read Coils Read from 1 to 2000 contiguous status of coils managed

by the server. Coils in the response message are packed
as one per bit of a byte, 1=ON and 0=OFF. If the
requested quantity of coils is not a multiple of 8, zeros
are padded in the final byte.

02 Read Discrete

Inputs

03 Read Holding

Registers

04 Read

InputRegisters

05 Write Single Coil Write a single output to either ON(1) or OFF(0) mapped

06 Write Single

Register

15 Write Multiple

Coils

Read from 1 to 2000 contiguous status of input status
managed by the server. Discrete inputs in the response
message are packed as one per bit of a byte, 1=ON and
0=OFF. If the requested quantity of inputs is not a
multiple of 8, zeros are padded in the final byte.
Read the contents of contiguous block of 1 to 127
holding registers. Data are packed as two bytes per
register; the first byte contains the high order bits.
Read the contents of contiguous block of 1 to 127 input
registers. Data are packed as two bytes per register; the
first byte contains the high order bits.

in coil section.
Write a value into a single holding register;

Force each coil in a sequence of coils to either ON or
OFF.

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16 Write multiple

Registers

Write values into a block of contiguous registers (1 to

120)

Data Field(s):

The data field varies in length depending on whether the message is a request or
a response to a packet. This field typically contains information required by the
slave device to perform the command specified or to pass back data to the
master device.

Error Check Field:

The Error Check Field consists of a 16-bit (2 byte) Cyclical Redundancy Check
(CRC16). It allows the receiving device to detect a packet that has been
corrupted with transmission errors.

RTU Framing

The example below shows a typical Q/R from a OC-485 interface card. In common
terms, the master device initiates a query asking slave device 2 for holding registers
starting at holding register 40051 (decimal 50) and including next 2 Registers (3 total).

Query Sample

Slave

Address

02 03 00 32 00 03 E5 FA

Function

Code

Starting

Register

“Hi Byte”

Starting

Register

“Lo Byte”

Number of

Registers
“Hi Byte”

Number of

Registers

“Lo Byte”

CRC16

“Hi Byte”

CRC16

“Lo Byte”

Response Sample

Slave

Address

02 03 6 01 58 00 FA 00 54 1B 0D

Function

Code

Count:

Bytes of

Data

Register

40051 Data

Hi Lo

Register

40052 Data

Hi Lo

Register

40053 Data

Hi Lo

CRC16

“Hi Byte

CRC16

“Lo Byte”

Slave address 2 responds to Function Code 3 with 6 bytes of hexadecimal data
and ends with CRC16 checksum.

Register values:40051 = 158(hex) = 344(decimal)

40052 = FA (hex) = 250 (decimal)
40053 = 54 (hex) = 84 (decimal)

3

Data Point

Automatic Battery Test
Enabled

Liebert Monitoring Group –Development

Liebert Nfinity

Supported Modbus Points

# of

Status Coil

10003 3 1 1

Scale Notes/ Units

Reg.

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Battery Charger On 10044 1 1
Inverter Ready 10047 1 1

Power Factor Correction
State 10050 1 1

Load On Inverter 10073 1 1
Bypass Active 10074 1 1
Replace Battery 10081 1 1
Battery Under Test 10082 1 1
Load On Battery 10128 1 1
Load On Bypass 10129 1 1
Load On Manual Bypass 10132 1 1

Load Transferred To
Bypass Due To UPS Fault

Transfer Inhibit 10146 1 1
Output Off Pending 10151 1 1

10134 1 1

Low Battery - Shutdown
Imminent 10152 1 1

Output Overload 10154 1 1
UPS Overload 10155 1 1
Output Off 10158 1 1

Check Air Filter - Replace 10170 1 1
Transformer Over

Temperature
Input Power Supply Fail 10186 1 1

10178 1 1

Internal Device
Communication Failure 10284 1 1

Device Active Alarm 10290 1 1
Main Control Warning 10291 1 1

Redundant Control Warning 10292 1 1
Control Module Failure 10293 1 1

Redundant Control Module
Failed 10294 1 1

User Interface Module
Failed 10295 1 1

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UPS Power Not Redundant 10296 1 1
Power Module Failure 10298 1 1
Battery Module Failure 10299 1 1
Power Module Warning 10300 1 1
Battery Module Warning 10301 1 1

Data Point

Input

Register

Holding

Register

# of

Reg. Scale Notes/ Units

Number Of Input Lines 30004 40004 1 1
Number Of Bypass Lines 30004 40004 1 1
Number Of Output Lines 30004 40004 1 1

Number Of Power Mod. 30010 40010 1 1

Bits 12 - 15
Bits 4 - 7
Bits 8 - 11

Number Of Battery Modules
Installed

30011 40011 1 1

Device Maximum Frame
Capacity

30023 40023 2 1
Device System Capacity 30025 40025 2 1 VA
Nominal Input Voltage 30027 40027 1 1 V
Nominal Output Voltage 30028 40028 1 1 V

Nominal Static Bypass
Switch Voltage 30029 40029 1 1 V

Nominal Input Frequency 30031 40031 1 10 Hz
Nominal Output Frequency 30032 40032 1 10 Hz

Nominal Power Factor 30033 40033 1 100
Nominal Battery Voltage 30034 40034 1 1 V
Auto Restart Delay 30051 40051 1 1 seconds

Device Auto Restart
Percent Setpt

30052 40052 1 1 %
Device Low Battery Time 30053 40053 1 1 min

Next Battery Auto Test
Time

30057 40057 1 1 minutes
Overload Alarm Limit 30067 40067 2 1 VA

Minimum Redundant Power
Modules 30074 40074 1 1

Load (Apparent Power) 30102 2 1 VA
Load (Real Power) 30104 2 1 W
Load / Capacity 30106 1 1 %
Input Frequency 30107 1 10 Hz
Output Frequency 30108 1 10 Hz
Bypass Frequency 30109 1 10 Hz

1 - 100% Charged
2 - Less than 100% Charged
3 - Charging
4 - Discharging

Battery Charge Status 30112 1

5 - Float Charging
6 - Equalize Charging

Battery Voltage 30113 1 1 V
Battery Time Remaining 30115 1 1 min

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Battery Charge Percentage 30116 1 1 %
Battery Temperature 30117 1 1 deg C

Transformer Temperature 30121 1 1 deg C

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Redundant Power Modules 30124 1 1

Active Power Module Count 30126 1 1
Battery Module Active

Count 30127 1 1
Battery Test Result 30130 1 1
Input Voltage L1 30153 1 1 V
Input Current L1 30154 1 1 A
Bypass Voltage L1 30159 1 1 V
Bypass Current L1 30160 1 1 A
Output Voltage L1 30163 1 1 V
Output Current L1 30164 1 1 A

Power Module Failure
Count 30304 1 1

Battery Module Failure
Count 30305 1 1

Power Module Warning
Count

Battery Module Warning
Count

30306 1 1

30307 1 1

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Liebert Nx

Supported Modbus Points

Data Point Status Coil # of Reg. Scale Notes / Units

Economode 10005 5
DC-To-DC Converter
On
Battery Charge
Compensation

Inverter Ready 10047
Power Factor

Correction State 10050
Battery Charge Mode 10051
Load On Inverter 10073
Bypass Active 10074
Battery Under Test 10082
Load On Battery 10128

Overload Transfer To
Bypass 10131

Input Switch Open 10137
Generator

Disconnected 10141
Bypass Transfer

Count Block 10147
Static Bypass Switch

Disabled 10148
Low Battery -

Shutdown Imminent
Output Overload 10154

UPS Load Joint
Mode 10156

Output Off 10158
Inverter

Unsynchronized 10160
Main Neutral Lost 10161
Fan Failure 10169

Ambient Over
Temperature 10173

Rectifier Over
Temperature 10174

Rectifier Inductor
Over Temperature 10175

Inverter Over
Temperature 10176

Inverter Inductor
Over Temperature

Battery Converter 10179

10042
10046

10152

10177

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Over Temperature
DC Bus Balancer

Over Temperature
Input Power Supply

Fail 10186
Input BrownOut 10189
Bad Input Frequency 10190

Bypass Phase
Rotation Error 10191

Bypass Phase Loss 10201
Bypass Input

Voltage/Frequency
Fault 10202

Output Fuse Blown 10217
Output Over Voltage 10219
Charger Failed 10234
Battery Fault 10235
Battery Contact Fail 10236
Battery Converter

Over Current 10237
Battery Converter

Fail 10238
DC Bus Balancer

Over Current 10239
DC Bus Balancer

Fault 10240
DC Bus 1 Power

Supply Fail 10251
Rectifier Fuse Fail 10257

Rectifier Startup
Failure 10258

Rectifier Fault 10259
Rectifier Current Limit 10260

Inverter DC Voltage
Low Shutdown 10262

Inverter Fault 10263
Inverter DC Offset
Overload
Inverter Contactor
Fail 10265

Inverter Current Limit 10266
Parallel Low Battery
Warning

Load Share Fault 10268
Parallel System Fault 10269

Parallel Connection
Error 10270

Parallel System
Overload 10271

Parallel Transfer To 1027 2

10180

10264

10267

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Static Bypass Switch
Inverter

Communication Fail 10281
Rectifier

Communication
Failure 10282
Parallel
Communication Fault

Operation Fault 10289

Data Point Input Register Holding Register # of Reg. Scale Notes / Units

Number of Input
Lines 30004 40004 1 1 Bits 12 - 15

Number of Bypass
Lines 30004 40004 1 1 Bits 4 - 7

Number of Output
Lines
Number Of
SubModules

Load Circuit Present 30013 40013 1
Module Number 30014 40014 1
Device Module Count 30015 40015 1
Device Redundant

Count 30016 40016 1
Device Module Mode 30017 40017 1

Nominal Power
Rating 30021 40021 2 VA

Nominal Input
Voltage 30027 40027 1 V

Nominal Output
Voltage
Nominal Static
Bypass Switch
Voltage 30029 40029 1 V

Nominal Input
Frequency 30031 40031 1 10 Hz

Nominal Output
Frequency 30032 40032 1 10 Hz

Nominal Power
Factor

Nominal DC Bus #1
Voltage 30035 40035 1 V

Nominal DC Bus #2
Voltage

10283

30004 40004 1 1 Bits 8 - 11
30009 40009 1

There are 16 possible
Load Circuits. So
each bit represents 1
load circuit. Load
Circuit 1 is bit 0, Load
Circuit 2 is bit 1 and
so on. If the bit is 1
then the Load Circuit
is supported.

30028 40028 1 V

30033 40033 1 100

30036 40036 1

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