Communication and expansion modules Modbus RTU communication module Manual • 02/2011
Low-Voltage Power Distribution and Electrical Installation Technology Answers for infrastructure.
Modbus RTU communication module
1 ___________________ Introduction 2 ___________________ Modbus module
Low-voltage power distribution and electrical installation engineering Communication and expansion modules Modbus RTU communication module Manual
02/2011 3ZW1012-0KT10-0AC0
3 ___________________ Modbus master 4 ___________________ Modbus protocol
Legal information Legal information Warning notice system This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are graded according to the degree of danger. DANGER indicates that death or severe personal injury will result if proper precautions are not taken. WARNING indicates that death or severe personal injury may result if proper precautions are not taken. CAUTION with a safety alert symbol, indicates that minor personal injury can result if proper precautions are not taken. CAUTION without a safety alert symbol, indicates that property damage can result if proper precautions are not taken. NOTICE indicates that an unintended result or situation can occur if the relevant information is not taken into account. If more than one degree of danger is present, the warning notice representing the highest degree of danger will be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to property damage.
Qualified Personnel The product/system described in this documentation may be operated only by personnel qualified for the specific task in accordance with the relevant documentation, in particular its warning notices and safety instructions. Qualified personnel are those who, based on their training and experience, are capable of identifying risks and avoiding potential hazards when working with these products/systems.
Proper use of Siemens products Note the following: WARNING Siemens products may only be used for the applications described in the catalog and in the relevant technical documentation. If products and components from other manufacturers are used, these must be recommended or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and maintenance are required to ensure that the products operate safely and without any problems. The permissible ambient conditions must be complied with. The information in the relevant documentation must be observed.
Trademarks All names identified by ® are registered trademarks of Siemens AG. The remaining trademarks in this publication may be trademarks whose use by third parties for their own purposes could violate the rights of the owner.
Disclaimer of Liability We have reviewed the contents of this publication to ensure consistency with the hardware and software described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the information in this publication is reviewed regularly and any necessary corrections are included in subsequent editions.
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3ZW1012-0KT10-0AC0 Ⓟ 02/2012 Technical data subject to change
Copyright © Siemens AG 2011. All rights reserved
Table of contents 1
2
3
4
Introduction................................................................................................................................................ 5 1.1
Purpose of this document ..............................................................................................................5
1.2
Further documentation...................................................................................................................5
1.3
Download address for software and documentation .....................................................................5
Modbus module ......................................................................................................................................... 7 2.1
Safety notes ...................................................................................................................................7
2.2
Device view ....................................................................................................................................8
2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5
Description .....................................................................................................................................9 Function .........................................................................................................................................9 Networking of the Modbus RTU communication module ..............................................................9 Communication status ...................................................................................................................9 Transferable variables ...................................................................................................................9 Factory settings............................................................................................................................10
2.4
Installation ....................................................................................................................................10
2.5
Connecting ...................................................................................................................................10
2.6
Dimension drawings.....................................................................................................................12
Modbus master ........................................................................................................................................ 15 3.1 3.1.1 3.1.2 3.1.3
Overview ......................................................................................................................................15 Function .......................................................................................................................................15 Hardware requirements ...............................................................................................................15 Software requirements.................................................................................................................15
3.2
Commissioning.............................................................................................................................16
Modbus protocol ...................................................................................................................................... 19 4.1 4.1.1 4.1.2
General information .....................................................................................................................19 System architecture .....................................................................................................................19 Defaults ........................................................................................................................................19
4.2
Function codes.............................................................................................................................20
4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.3.5.1 4.3.5.2 4.3.5.3
Register........................................................................................................................................23 Structure of the register ...............................................................................................................23 Register overview ........................................................................................................................24 General registers .........................................................................................................................26 Configuration registers.................................................................................................................27 Measured value registers.............................................................................................................28 Measured value registers.............................................................................................................28 Decoding of float measured values (in accordance with IEEE 754:2008)...................................30 Decoding of integer measured values .........................................................................................31
Index........................................................................................................................................................ 33
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Table of contents
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Introduction 1.1
1
Purpose of this document
Purpose This manual describes the Modbus RTU communication module, the RS-485 Modbus master software, and the Modbus protocol.
Target group This manual is intended for planners, operators, commissioning engineers, and service and maintenance personnel.
Required basic knowledge A general knowledge of the field of electrical engineering is required to understand this manual. Knowledge of the relevant safety regulations and standards is required for installing and connecting the device.
1.2
Further documentation You can find further details in the following documents: ● Modbus RTU/ASCII Communication Module Operating Instructions
1.3
Download address for software and documentation Download address (www.siemens.com/lowvoltage/communication-module)
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Introduction 1.3 Download address for software and documentation
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Modbus module 2.1
2
Safety notes DANGER Hazardous Voltage Will cause death, serious injury or considerable property damage. Observe the safety instructions on the device as well as those in the operating instructions and manual. The device may only be installed and commissioned by an approved electrical engineer. The applicable safety and accident prevention regulations must be observed. The device must not be opened. When planning and installing electrical systems, always ensure adherence to the pertinent directives, regulations and provisions of the respective country.
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Modbus module 2.2 Device view
2.2
Device view
Figure 2-1
Modbus RTU communication module
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Modbus module 2.3 Description
2.3
Description
2.3.1
Function The energy registers and parameters of a measuring device can be read out with the Modbus RTU communication module.
2.3.2
Networking of the Modbus RTU communication module The following diagram shows an example of the use of the Modbus RTU communication module. The minimum configuration consists of a counter, a communication module, and a master (with an RS-232/RS-485 converter if applicable).
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Modbus networking
Communication status A green LED indicates the status of the communication:
2.3.4
LED signal
Status
LED flashes
No communication
LED lights up permanently
Communication active
Transferable variables The transferable measured variables can be found in the description of the Modbus protocol, SectionMeasured value registers (Page 28).
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Modbus module 2.4 Installation
2.3.5
Factory settings A button for resetting the module to factory settings is located on top of the device. Baud rate:
2.4
19 200 bit/s
Protocol:
Modbus RTU
Address:
001
Parity:
None
Stop bits:
1
Data format:
Float (binary 32 in accordance with IEEE 754:2008)
Installation The module is positioned next to the E-counter in such a way that their IrDA interfaces are exactly opposite each other.
2.5
Connecting The device is wired via ● 2 supply terminals ● 5 terminals for data transfer Terminal
Function
L, N
Phase and neutral conductors
D+/D-
Data transfer via RS-485
RT+/RT-
RS-485 terminating resistor Only connected to terminals D+/D if the module is the first or last node of the bus cable.
Shield
Terminal for cable shielding
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Modbus module 2.5 Connecting 1 /
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Figure 2-3
Wiring
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Modbus module 2.6 Dimension drawings
2.6
Dimension drawings
All dimensions in mm.
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Modbus module 2.6 Dimension drawings
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Modbus master 3.1
Overview
3.1.1
Function
3
The Modbus master application enables fast configuration of the Modbus RTU communication module.
3.1.2
Hardware requirements ● Modbus RTU communication module ● Counter ● RS-232/RS-485 converter or USB/RS-485 converter ● Windows PC with Modbus master application
3.1.3
Software requirements Minimum requirements: ● Windows XP/2000 ● Framework Microsoft .NET 1.1
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Modbus master 3.2 Commissioning
3.2
Commissioning
Modbus master application The Modbus master is organized into three tabs: Tab
Description
Counters
Management of the modules
Communication
Management of the COM port
Settings
Configuration of the connected Modbus RTU communication module
Resetting the energy registers
Preparation
Figure 3-1
"Communication" tab
Only one Modbus RTU communication module must be connected for configuring. First, the "Communication" tab of the corresponding COM port must be selected. The values must be set to the factory defaults for the initial configuration and after resetting: 19 200 bit/s, 8 data bits, no parity, 1 stop bit, Modbus RTU
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Modbus master 3.2 Commissioning
Adding an interface
Figure 3-2
"Counters" tab
A new module is integrated into the Modbus network as follows: ● Open the "Counters" tab ● Click on the "New" button ● Enter a name for the module in the "Alias" field ● Enter the Modbus address The default address for a not yet configured interface is "001" ● Click on the "Add" button All added modules are saved in an .xml file in the application folder. The .xml file can be exported to a freely selectable folder using the "Export" button. An exported .xml file can be integrated again using the "Import" function. NOTICE Changing the Modbus address on the "Counters" tab only changes the entry in the .xml file. The change is NOT transferred to the Modbus RTU communication module.
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Modbus master 3.2 Commissioning
Settings
Figure 3-3
"Settings" tab
The parameters of the Modbus RTU communication module can be configured on the "Settings" tab. The following are available for selection: ● Transfer mode: Modbus RTU/ASCII ● Baud rate: 1 200 … 38 400 bit/s ● Modbus address of the communication module: 001 … 247 ● Parity: None, even, odd ● Stop bits: 1, 2 ● Read-out format: Float (binary 32 in accordance with IEEE 754:2008) or integer (64 bits)
Resetting counters On the "Settings" tab, the energy registers (active energy and/or reactive energy) of the connected counter can be reset (only for non-calibrated counters).
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Modbus protocol 4.1
General information
4.1.1
System architecture Use of the Modbus protocol for the Modbus communication interface 7KT1 907 is described below. The communication modules support data transfer for Modbus RTU and Modbus ASCII.
4.1.2
Defaults The default settings are: Report
Modbus RTU
Modbus address
001
Baud rate
19 200 bit/s
Parity
None
Stop bits
1
Communication
Float (binary 32 in accordance with IEEE 754:2008)
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Modbus protocol 4.2 Function codes
4.2
Function codes
Function codes The interface supports the Modbus function codes 03 (Read holding registers) and 06 (write single register).
Reading out registers (function code 03) This function code is used for reading out a register block. The start register and the number of registers to be read out are specified in the message frame. Note Due to the finite length of the Modbus message frame, several requests are required to read out all registers. The start address and the number of registers to be read out must be adapted accordingly: Example: Poll No. 1 Poll No. 2 Poll No. 3
Start address 4099 Start address 4197 Start address 4297
Number of registers to be read out 100 Number of registers to be read out 100 Number of registers to be read out 10
Request message frame ADR
0x03
STh
STl
NRh
ADR
Modbus address 1 … 247 (0x01 … 0XF7)
0x03
Function code for reading out
NRl
STh
Start address (high byte)
STl
Start address (low byte)
NRh
Number of registers to be read out (high byte)
NRl
Number of registers to be read out (low byte)
CRCh
Checksum Modbus CRC 16 Modbus (high byte)
CRCl
Checksum Modbus CRC 16 Modbus (low byte)
CRCh
CRCl
Example (hex): 02 03 10 17 00 64 F0 D6 Address: 0x02 = Device address 2 Function code: 0x03 = read Start address: 0x1017 = Register 4119dec Number of registers to be read out: 0x0064 = 100dec CRC 16: 0xF0D6 = checksum for the message frame
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Modbus protocol 4.2 Function codes Reply message frame ADR
0x03
ADR
BC
RegCont
CRCh
CRCl
Modbus address 1 … 247 (0x01 … 0xF7)
0x03
Function code for reading out
BC
Byte count (number of user data bytes)
RegCont
Register contents (data)
CRCh
Checksum Modbus CRC 16 Modbus (high byte)
CRCl
Checksum Modbus CRC 16 Modbus (low byte)
Writing to a register (function code 06) This function code is used for writing to individual registers. The address of the register to be written to and the value to be written are specified in the message frame. If transferred correctly, the slave supplies the request message frame as the reply (echo). Request message frame ADR
0x06
ADR
RAh
RAl
RVh
RVl
CRCh
CRCl
Modbus address 1 … 247 (0x01 … 0xF7)
0x06
Function code "Writing to a register"
RAh
Register address (high byte)
RAl
Register address (low byte)
RVh
Value to be written (high byte)
RVl
Value to be written (low byte)
CRCh
Checksum Modbus CRC 16 Modbus (high byte)
CRCl
Checksum Modbus CRC 16 Modbus (low byte)
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Modbus protocol 4.2 Function codes Example: Changing the data format from float (binary32 – default) to integer in the slave with Modbus address 1 Message frame master: 01 06 10 15 00 01 5D 0E Modbus device address: 0x01 = Device address 1 Function code: 0x06 = Write Register to be written to: 0x1015 = Register 4117dec Value to be written: 0x0001 = 1dec (read-out to "Int" - see table in Sect. Configuration registers (Page 27)) CRC 16: 0x5D0E = Checksum for the message frame Reply message frame slave (if transfer correct): 01 06 10 15 00 01 5D 0E Note Before the change to the configuration(s) takes effect, a "Verify" message frame must be sent. To do this, register 4116dec must be set to "1". The corresponding message frame in this example is as follows: 01 06 10 14 00 01 0C CE Here too, the slave returns the request frame if the transfer was successful: 01 06 10 14 00 01 0C CE
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Modbus protocol 4.3 Register
4.3
Register
4.3.1
Structure of the register The configuration parameters and the measured values are saved in registers (1 register = 2 bytes) in the modules. The values are transferred in "big-endian" format, i.e. the high byte is sent first, and then the low byte. Since the measured values of the counters are stored in either 2 or 4 registers, data reconstruction must be on a cross-register basis: Example 1:Integer format of the active energy L1, T1, _import | 8 bytes | register 4119 … 4122
Example 2: Integer format of the active power L1 | 4 bytes | register 4151 … 4152
Whether a measured value is stored in 2 or 4 registers depends on the one hand on the measured value itself and, on the other, on the data type. It is possible to save and transfer the values in float (default) or integer format. In float format, the data is always stored in 2 registers (binary 32 in accordance with IEEE 754:2008), and in integer format, it depends on the measured value (see table in Sect. Measured value registers (Page 28)).
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Modbus protocol 4.3 Register
4.3.2
Register overview
Register
Description
Dec
Hex
4099
0x1003
4100
0x1004
4101
Notes
Counter type 3-phase
Singlephase
Device type
x
x
Firmware version
x
x
0x1005
Overflow alarm
x
x
4102
0x1006
Power tariff
x
x
4104
0x1008
PID (product identification) bytes 1 and 2
x
x
4105
0x1009
PID – Bytes 3 and 4
x
x
4106
0x100A
PID – Bytes 5 and 6
x
x
4107
0x100B
PID – Bytes 7 and 8
x
x
4108
0x100C
PID – Bytes 9 and 10
x
x
4109
0x100D
PID – Bytes 11 and 12
x
x
4110
0x100E
PID – Bytes 13 and 14
x
x
4111
0x100F
Protocol type
x
x
4112
0x1010
Data transfer rate
x
x
4113
0x1011
Parity
x
x
4114
0x1012
Stop bits
x
x
4115
0x1013
Modbus address
x
x
4116
0x1014
Control command interface resetting
x
x
4117
0x1015
Data format
x
x
4118
0x1016
Control command reset energy counter
x
x
4119
0x1017
Active energy L1, T1, _import (kWh)
x
x
4123
0x101B
Active energy L2, T1, _import (kWh)
x
4127
0x101F
Active energy L3, T1, _import (kWh)
x
4131
0x1023
Active energy Σ T1, _import (kWh)
x
4135
0x1027
Active energy L1, T2, _import (kWh)
x
4139
0x102B
Active energy L2, T2, _import (kWh)
x
4143
0x102F
Active energy L3, T2, _import (kWh)
x
4147
0x1033
Active energy Σ T2, _import (kWh)
x
4151
0x1037
Active power L1 (kW)
x
4153
0x1039
Active power L2 (kW)
x
4155
0x103B
Active power L3 (kW)
x
4157
0x103D
Active power Σ (kW)
x
4161
0x1041
Active energy L1, T1, _export (kWh)
x
4165
0x1045
Active energy L2, T1, _export (kWh)
x
4169
0x1049
Active energy L3, T1, _export (kWh)
x
4173
0x104D
Active energy Σ T1, _export (kWh)
x
4177
0x1051
Active energy L1, T2, _export (kWh)
x
4181
0x1055
Active energy L2, T2, _export (kWh)
x
4185
0x1059
Active energy L3, T2, _export (kWh)
x
General registers (function code 03) Sect. General registers (Page 26)
Configuration registers (function code 06) Sect. Configuration registers (Page 27)
Measured value registers (function code 03) Sect. Measured value registers (Page 28)
x
x
x
x
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Modbus protocol 4.3 Register
Description
Register
Notes
Counter type 3-phase
Dec
Hex
4189
0x105D
Active energy Σ T2, _export (kWh)
x
4193
0x1061
Reactive energy L1, T1, _import (kvarh)
x
4197
0x1065
Reactive energy L2, T1, _import (kvarh)
x
4201
0x1069
Reactive energy L3, T1, _import (kvarh)
x
4205
0x106D
Reactive energy Σ T1, _import (kvarh)
x
4209
0x1071
Reactive energy L1, T2, _import (kvarh)
x
4213
0x1075
Reactive energy L2, T2, _import (kvarh)
x
4217
0x1079
Reactive energy L3, T2, _import (kvarh)
x
4221
0x107D
Reactive energy Σ T2, _import (kvarh)
x
4225
0x1081
Reactive energy L1, T1, _export (kvarh)
x
4229
0x1085
Reactive energy L2, T1, _export (kvarh)
x
4233
0x1089
Reactive energy L3, T1, _export (kvarh)
x
4237
0x108D
Reactive energy Σ T1, _export (kvarh)
x
4241
0x1091
Reactive energy L1, T2, _export (kvarh)
x
4245
0x1095
Reactive energy L2, T2, _export (kvarh)
x
4249
0x1099
Reactive energy L3, T2, _export (kvarh)
x
4253
0x109D
Reactive energy Σ T2, _export (kvarh)
x
4257
0x10A1
Reactive power L1 (kvar)
x
4259
0x10A3
Reactive power L2 (kvar)
x
4261
0x10A5
Reactive power L3 (kvar)
x
4263
0x10A7
Reactive power Σ (kvar)
x
4267
0x10AB
Voltage L1-N (V)
x
4269
0x10AD
Voltage L2-N (V)
x
4271
0x10AF
Voltage L3-N (V)
x
4273
0x10B1
Voltage L1-L2 (V)
x
4275
0x10B3
Voltage L2-L3 (V)
x
4277
0x10B5
Voltage L3-L1 (V)
x
4279
0x10B7
Current L1 (A)
x
4281
0x10B9
Current L2 (A)
x
4283
0x10BA
Current L3 (A)
x
4285
0x10BD
Apparent power L1 (kVA)
x
4287
0x10BF
Apparent power L2 (kVA)
x
4289
0x10C1
Apparent power L3 (kVA)
x
4291
0x10C3
Apparent power Σ (kVA)
x
4295
0x10C7
Power factor cos φ L1
x
4297
0x10C9
Power factor cos φ L2
x
4299
0x10CB
Power factor cos φ L3
x
4301
0x10CD
Power factor cos φ Σ
x
4303
0x10CF
Frequency (Hz)
x
Singlephase x
x
x
x
x
x
x
x
x
x
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Modbus protocol 4.3 Register
4.3.3
General registers
Register (dec)
Designation
Description
4099
Device type
Code for communication monitoring 0dec 1dec 3dec
No IR communication with the counter counter 3-phase counter 1-phase
4100
Firmware version
Firmware version, version of the interface
4101
Alarm overflow
This register adopts a value other than zero if the counter detects voltage or current values that exceed the nominal limit values. The low byte of this register is encoded as follows (see below)*) The following rules apply: OFV x OFI x n.u.
Voltage exceeded (to phase x with x є [1, 2, 3]) current exceeded (to phase x with x є [1, 2, 3]) not used Tariff 1 used Tariff 2 used
4102-03
Power tariff
0 1
4104-10
PID
Character string for product identification (max. 14 bytes)
*)
4101 alarm overflow. The low byte of this register is encoded as follows:
n.u.
n.u.
OFV 3
OFI 3
OFV 2
OFI 2
OFV 1
OFI 1
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Modbus protocol 4.3 Register
4.3.4
Configuration registers These registers are used for configuring the interface and for resetting the energy values of the counter (only possible with non-MID-counters). Note For the configuration changes to become effective, register 4116 must be set to "1" at the end. This does not apply for register 4118. The changes are applied immediately here.
Register (dec)
Designation
4111
Protocol type
4112
4113
Baud rate
Parity
Description 0dec
Modbus protocol RTU
1dec
Modbus protocol ASCII
The following data transfer rates are available: 1.200
0x04B0
2.400
0x0960
4.800
0x12C0
9.600
0x2580
19.200
0x4B00
38.400
0x9600
0dec
None
1dec
Even
2dec
Odd
4114
Stop bits
1 or 2
4115
Modbus address
1 – 247dec (0x0001 … 0x00F7)
4116
Interface resetting
0dec
All modifications ineffective
1dec
All modifications effective
Data format
0dec
Measured variables encoded as 32-bit float values (see Sect. Decoding of float measured values (in accordance with IEEE 754:2008) (Page 30))
1dec
Measured variables encoded as integers (see Sect. Decoding of integer measured values (Page 31))
1dec
Resetting the counter registers relating to the active energy
2dec
Resetting the counter registers relating to the reactive energy
3dec
Resetting all registers
4117
4118
Resetting energy counters
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Modbus protocol 4.3 Register
4.3.5
Measured value registers
4.3.5.1
Measured value registers These registers contain all the measured variables the counter sends via the IR interface to the communication module. All measured variables in the 32-bit floating-point format (IEEE 754:2008) are encoded as standard, i.e. each measured value is stored in 2 registers: Example:"Active energy L1, T1, _import (kWh)" per register 4119 and 4120; registers 4121 and 4122 are not used here but remain reserved for integer read-out. To obtain the integer representation, register 4117 must be set (see Sect. Configuration registers (Page 27)). The following table applies in integer mode:
Register dec
Definition
Availability depending on the connected Length in bytes counter type (Integer format) 3-phase
Single-phase
4119
Active energy L1, T1, _import (kWh)
x
x
4123
Active energy L2, T1, _import (kWh)
x
8
4127
Active energy L3, T1, _import (kWh)
x
8
4131
Active energy Σ T1, _import (kWh)
x
8
4135
Active energy L1, T2, _import (kWh)
x
4139
Active energy L2, T2, _import (kWh)
x
8
4143
Active energy L3, T2, _import (kWh)
x
8
4147
Active energy Σ T2, _import (kWh)
x
4151
Active power L1 (kW)
x
4153
Active power L2 (kW)
x
4
4155
Active power L3 (kW)
x
4
4157
Active power Σ (kW)
x
8
4161
Active energy L1, T1, _export (kWh)
x
4165
Active energy L2, T1, _export (kWh)
x
8
4169
Active energy L3, T1, _export (kWh)
x
8
4173
Active energy Σ T1, _export (kWh)
x
4177
Active energy L1, T2, _export (kWh)
x
4181
Active energy L2, T2, _export (kWh)
x
x
8
8
8 x
x
4
8
8 x
8 8
4185
Active energy L3, T2, _export (kWh)
x
8
4189
Active energy Σ T2, _export (kWh)
x
8
4193
Reactive energy L1, T1, _import (kvarh)
x
4197
Reactive energy L2, T1, _import (kvarh)
x
8
4201
Reactive energy L3, T1, _import (kvarh)
x
8
4205
Reactive energy Σ T1, _import (kvarh)
x
4209
Reactive energy L1, T2, _import (kvarh)
x
4213
Reactive energy L2, T2, _import (kvarh)
x
x
8
8 x
8 8
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Manual, 02/2011, 3ZW1012-0KT10-0AC0
Modbus protocol 4.3 Register
Register dec
Definition
Availability depending on the connected Length in bytes counter type (Integer format) 3-phase Single-phase
4217
Reactive energy L3, T2, _import (kvarh)
x
8
4221
Reactive energy Σ T2, _import (kvarh)
x
8
4225
Reactive energy L1, T1, _export (kvarh)
x
4229
Reactive energy L2, T1, _export (kvarh)
x
8
4233
Reactive energy L3, T1, _export (kvarh)
x
8
4237
Reactive energy Σ T1, _export (kvarh)
x
4241
Reactive energy L1, T2, _export (kvarh)
x
4245
Reactive energy L2, T2, _export (kvarh)
x
8
4249
Reactive energy L3, T2, _export (kvarh)
x
8
4253
Reactive energy Σ T2, _export (kvarh)
x
8
4257
Reactive power L1 (kvar)
x
4259
Reactive power L2 (kvar)
x
4261
Reactive power L3 (kvar)
x
4
4263
Reactive power Σ (kvar)
x
8
4267
Voltage L1-N (V)
x
4269
Voltage L2-N (V)
x
4
4271
Voltage L3-N (V)
x
4
4273
Voltage L1-L2 (V)
x
4
4275
Voltage L2-L3 (V)
x
4
4277
Voltage L3-L1 (V)
x
4
4279
Current L1 (A)
x
4281
Current L2 (A)
x
4
4283
Current L3 (A)
x
4
4285
Apparent power L1 (kVA)
x
4287
Apparent power L2 (kVA)
x
4
4289
Apparent power L3 (kVA)
x
4
4291
Apparent power Σ (kVA)
x
4295
Power factor cos φ L1
x
4297
Power factor cos φ L2
x
4
4299
Power factor cos φ L3
x
4
4301
Power factor cos φ Σ
x
4
4303
Frequency (Hz)
x
x
8
8 x
x
8
4 4
x
x
x
4
4
4
8 x
x
4
4
Abbreviations: T1/T2 stands for tariff 1 and tariff 2. The symbol Σ represents the total (over all three phases) Export/import: Indicates whether the energy is generated (exported) or consumed (imported).
Modbus RTU communication module Manual, 02/2011, 3ZW1012-0KT10-0AC0
29
Modbus protocol 4.3 Register
4.3.5.2
Decoding of float measured values (in accordance with IEEE 754:2008) Data reconstruction is regulated in IEEE 754:2008. Below is just a brief example: Example: Active energy L1, T1, _import, 4 bytes (2 registers) The active energy L1, T1, _import is encoded in registers 4119 and 4120 (4121 and 4122 are not used in float mode).
Measured value:
Sign: Exponent: Mantissa
Modbus RTU communication module
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Manual, 02/2011, 3ZW1012-0KT10-0AC0
Modbus protocol 4.3 Register
4.3.5.3
Decoding of integer measured values The following rule has been defined for the reconstruction of the data transferred in integer mode: Measured values encoded in 4 bytes (2 registers) The values saved in these registers must be divided by 10 000dec to reconstruct the original value. Example: Active power L1 (kW) The active power for phase L1 is encoded in registers 4151 and 4152 (cf. table in Sect. Register overview (Page 24))
Byte A:
0x00
Byte B:
0x01
Byte C:
0xDE
Byte D:
0x4F
Transferred value: 0x001DE4F Integer value (unsigned): 122.447dec Measured value:
Modbus RTU communication module Manual, 02/2011, 3ZW1012-0KT10-0AC0
31
Modbus protocol 4.3 Register Measured values encoded in 8 bytes (4 registers) In this case, reconfiguration of the original value is a bit more complicated: The int value encoded in the upper 4 bytes must be multiplied by 109 (1 000 000 000dec). The value of the lower 4 bytes must be added to this result. The resulting value must then be divided by 10 000dec to obtain the measured value. Example: Active energy L1, T1, _import The active energy L1, T1, _import is encoded in registers 4119 … 4122.
Transferred data stream (hex): 00 00 00 04 12 98 E9 C4 Byte A:
0x00
Byte E:
0x12
Byte B:
0x00
Byte F:
0x98
Byte C:
0x00
Byte G:
0xE9
Byte D:
0x04
Byte H:
0xC4
Upper 4 bytes (upper double word): 0x00000004 = 4dec , ×109 → 4 000 000 000dec Lower 4 bytes (lower double word): 0x1298E9C4 = 312 011 204dec Integer value (unsigned): 4 000 000 000dec + 312 011 204dec = 4 312 011 204dec Measured value:
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Manual, 02/2011, 3ZW1012-0KT10-0AC0
Index Registers, structure, 23 More information, 5
C Communication status, 9 Connecting, 10
N Networking, 9
D
R
Device view, 8 Dimension drawing, 12
Required basic knowledge, 5
F
S Safety instructions, 7
Factory settings, 10
I
T Transferable variables, 28
Installation, 10
L
V Variables, non-transferable, 28
LED, 9
M
W Wiring, 10
Minimum configuration, 9 Modbus master application Add interface, 17 Communication, 16 Counters, 17 Function, 15 Hardware requirements, 15 Reset counters, 18 Settings, 18 Software requirements, 15 Modbus protocol Decoding of float measured values, 30 Decoding of integer measured values, 31 Default settings, 19 Function codes, 20 Register, overview, 24 Registers, configuration, 27 Registers, measured variables, 28 Registers, resetting the energy values, 27
Modbus RTU communication module Manual, 02/2011, 3ZW1012-0KT10-0AC0
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Index
Modbus RTU communication module
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Manual, 02/2011, 3ZW1012-0KT10-0AC0
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Subject to change without prior notice Order No.: 3ZW1012-0KT10-0AC0 © Siemens AG 2011
