Supported Modbus Features - Siemens 9810 Series User Manual

Supported Modbus features

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Related Topics
• Configuring your meter as a Modbus master using ION Setup
Your meter supports specific Modbus data classes, data formats, function codes
and commands.
Modbus data classes
Class
Coils
Input status
Input registers
Holding registers
Modbus data formats
Format
Unsigned 16-bit
Signed 16-bit
Unsigned 32-bit
Signed 32-bit
Unsigned 32B-M10K
Signed 32B-M10K
IEEE float 1
Packed Boolean for inputs
Packed Boolean for coils
Unsigned 16-bit read/write
Signed 64 bit
1 Meters acting as Modbus masters support two versions of IEEE float with different word orders:
high/low = Big Endian, low/high = Little Endian.
16-bit data (one word) is transmitted with most-significant byte first and least-
significant byte second.
32-bit data (two words) is transmitted with the most-significant word first and the
least-significant word second.
Modbus function codes
Function Description
1 Read coil status
2 Read input status
3 Read holding registers
4 Read input registers
5 Write to a coil
6 Write to a holding register
15 Write to multiple coils
16 Write to multiple holding registers
17 Report slave ID (serial only)
Description
Digital bits that can be read and written to
Digital bits that can be read
16-bit integers that can be read
16-bit integers that can be read and written to
Type
Integer
Integer
Integer
Integer
Integer
Integer
Floating point
Integer
Integer
Integer
Integer
Communications
# of Modbus registers used
1
1
2
2
2
2
2
1
1
1
4
Master/slave
Master and slave
Master and slave
Master and slave
Master
Master
Master and slave
Master
Master and slave
Master and slave
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