2. Device-operated functions
Function code
Description
Dec
Hex
1
0x01
Binary output status read
2
0x02
Binary input status read
3
0x03
Memory register read
4
0x04
Input register read
5
0x05
Record of one binary output
6
0x06
Record of one memory register
15
0x0F
Record of many binary outputs
16
0x10
Record of many memory registers
Table 2: Device-operated functions.
Binary output status read (code 1) - The function allows, with one message, to read many
subsequent binary output reads. The attempt to read the non-existing binary output leads to error message.
Example: output 7-18 read
Request
Response
Field name
Hex
Field name
Hex
Function Code
0x01
Function Code
0x01
Register address – high part
0x00
Bytes
0x02
Register address – low part
0x06
14-7 outputs status
0xAC
Number of binary outputs – high part
0x00
18-15 output status
0x0B
Number of binary outputs – low part
0x0C
Table 3: Exemplary binary output read.
Output No.
14
13 12
11 10 9
8
7
-
-
-
-
18
17
16 15
Value Read
Hex
0xAC
0x0B
Bit
1
0
1
0
1
1
0
0
0
0
0
0
1
0
1
1
Input Status
ON OFF ON OFF ON ON OFF OFF
-
-
-
- ON OFF ON ON
Table 4: Interpretation of binary output statuses
3