59
ifm
Device Manual IO-Link Master with Modbus interface CabinetLine 8 Ports IP 20 (AL1940)
05 / 2018
Configuration
Modbus
>
Supported function codes
13676
The AL1940 supports the following function codes for read and/or write access to the Modbus register:
Function
code
Function name / description
03 (0x03)
Read Multiple Registers
04 (0x04)
Read Input Register
06 (0x06)
Write Single Register
16 (0x10)
Write Multiple Registers
23 (0x17)
Read/Write Multiple Registers
43 (0x2B)
Read Device Identification
Detailed information about the function codes:
→ MODBUS-TCP specification
>
Use acyclic services
11046
The AL1940 has a command interface to execute acyclic commands. A cyclic command consists of a
request and a response.
Register area
Contents
Access
Start
address
Length
(words)
500
22
Command Request Channel (Fieldbus PLC >>> IO-Link Master)
r/w
0
22
Command Response Channel (IO-Link Master >>> Fieldbus PLC)
r
Structure of the acyclic command channel:
→
Acyclic Command Channel
(
General procedure of the acyclic communication:
1 Write Command Request
►
In the request channel: Write required data (except for [User ID]).
>
Write required [User ID].
>
Changed [User ID] signals a new command.
>
In the response channel: registers are reset to 0.
>
Acyclic command channel is blocked.
>
Processing of the command is started.
2 Check status
►
In the response channel: Check [Command Status] register.
>
If [Command Status] <> 0: continue with step 3
>
If [Command Status] == 0: repeat step 2.
3 Read Command Response
►
In the response channel: read returned user data.
>
Acyclic command channel is released.
