GFK-2423G
Nov 2019
13
RTU Function Codes Supported
The Serial Communications module supports the following RTU Function Codes.
Function
Code Value
Function Name
RTU Master Command
Slave
Reference
Type
Valid as
Broadcast
Query?
Dec. Hex.
1
01
Read Output Table
Send RTU Read/Force/Preset Query
%Q
No
2
02
Read Input Table
Send RTU Read/Force/Preset Query
%I
No
3
03
Read Registers
Send RTU Read/Force/Preset Query
%R
No
4
04
Read Analog Inputs
Send RTU Read/Force/Preset Query
%AI
No
5
05
Force Single Output
Send RTU Read/Force/Preset Query
%Q
Yes
6
06
Preset Single Register
Send RTU Read/Force/Preset Query
%R
Yes
7
07
Read Exception Status
Send RTU Read/Force/Preset Query
%Q
No
8
08
Loopback/Maintenance
Send RTU Diagnostic Query
N/A
No
15
0F
Force Multiple Outputs
Send RTU Read/Force/Preset Query
%Q
Yes
16
10
Preset Multiple Registers
Send RTU Read/Force/Preset Query
%R
Yes
17
11
Report Device Type
Send RTU Read/Force/Preset Query
N\A
No
67
43
Read Scratch Pad Memory
Send RTU Read/Force/Preset Query
N\A
No
Product Revision History
Revision
Date
Description
IC200CMM020-GA Nov 2019
Following Emerson’s acquisition of this product, changes have been made to apply appropriate
branding and registration of the product with required certification agencies. No changes to
material, process, form, fit or functionality.
IC200CMM020-FA Oct 2016
EU RoHS compliant module per directive 2011/65/EU dated 8-June-2011. No changes to
features, performance or compatibility.
IC200CMM020-EA Feb 2012
Label change. No changes to features, performance or compatibility.
IC200CMM020-DA Mar 2011
Labeling change. No changes to compatibility, functions or performance.
IC200CMM020-CA Mar 2010
Changed manufacturing location. No changes to compatibility, functionality or performance.
IC200CMM020-BA Oct 2008
Updated Power Supply OK signal circuitry.
IC200CMM020-AA Jan 2006
Initial product release
Operational Notes and Open Issues
•
Application programs should use the “Command Ready” indication to synchronize the first command to the
module upon Genius NIU system power up.
•
Do not set the serial port baud rate higher than 19200 baud.
•
The Data Length parameter is ignored for function codes 5 and 6. The Data Start and Data Length parameters are
ignored for function codes 7 and 17. For function code 67, the Data Start parameter must be set to 1 and the Data
Length parameter must be set to 62.
•
Firmware update occurs at 19200 baud. If the module is configured for operation at a different baud rate and you
wish to perform a firmware update, first change the Genius NIU’s serial port configuration and select 19200 baud.
Then, when running the Winloader update utility, select 19200 baud. Then return the GNIU’s baud rate setting to
its original value.
•
If the Genius bus scan rate is slower than the PLC CPU’s sweep time, a command may be
written into %AQ memory
at the PLC CPU, but overwritten with a newer command before the original command is transferred to the GNIU for
processing. It will appear that the original command has been “dropped”.