Function Codes 01 (Read Coils) And 02 (Read Discrete Inputs) - Siemens SIRIUS 3RW5 series Manual
Soft starters and solid-state
switching devices modbus tcp communication module
Hide thumbs
Also See for SIRIUS 3RW5 series:
- Equipment manual (214 pages) ,
- Manual (116 pages) ,
- Equipment manual (150 pages)
Table of Contents
Advertisement
7.2.1
Function Codes 01 (Read Coils) and 02 (Read Discrete Inputs)
These functions enable the reading of individual bits from the 3RW5 bit memory area by the
MODBUS client system.
Function Codes 01 and 02 behave in the same way here and supply an identical feedback
signal. A valid offset from the bit memory area is expected as the start address. Up to
2000 bits can be read per telegram.
If a number that is not equal to a multiple of eight bits is called up, the remaining bits are
filled with zeros. The number of bytes n always refers to the number of fully returned bytes.
Note
Start address and number of Coils
The start address and the number of coils must be within the valid range.
Request telegram
Address Field
7 bytes
-
Response telegram
Address Field
7 bytes
-
Example
Reading in bypass operation mode "internal bypass" (Operation / bypass active):
● Address field: The address of the 3RW5 soft starter is not entered in the example (-).
● The bit address of "Operation / bypass active" is 0x84EF.
● As feedback, the status "Operation / bypass active" (bit 7) is returned with a logical one
(0x80).
You will find the data table for the soft starter diagnostics in chapter Soft starter diagnostics
(Page 82).
SIRIUS 3RW5 Modbus TCP communication module
Manual, 03/2018, A5E43676481002A/RS-AA/001
Function Code
1 byte
0x01
Function Code
1 byte
0x01
Messages and diagnostics
Start address
2 bytes
0x84EF
Number of bytes n
1 byte
0x01
7.2 Function Codes
Number of bits
2 bytes
0x0001
Bit status
n bytes
0x80
53
Advertisement
Table of Contents
