Hi,
I’m trying to map modbus registers from Hamilton probes into DeltaV through an AB7072.
I seem to constantly get the red subnet light issue. Even when its green, getting to valid data state is complex and requires a handshaking code/extra DSTs which I want to avoid.
Do I have to use Tx/Rx or/and Control/Status words?
Thanks in advance!
Kind Regards,
Christopher
Hello,
You do not have to use the control/status word for the device to be functional.
You can select Cyclical
Thanks Kevin,
I will update the development setup we have an try again.
Will the subnet light always show red if there’s no send/receive or control/status words in place?
I think the device here is already set to cyclic and without the above items there was no registers visible on DeltaV
The Subnet will show red when there is unresolvable error, and/or up the subnet is not running.
-Kevin
Hi Kevin,
I’ve just gone back to 1in1out to try and understand why I cannot write.
I’m trying to read (successfully) “4288 operator level” which is indicated as 3/4/16 in the Hamilton manual.
I’m not able to write the same register using function code 16 (0x010) also as per the Hamilton manual. DO.cfg (16.0 KB)
I’ve assumed the write deals with the register the same way, starting at 4287, same size etc.
But simply including a write command is generating a subnet error.
From reading other posts I’ve increased/decreased the timings and retries.
Not sure what’s left to configure but I’m a bit lost now.
Any insight is much appreciated.
Kind Regards,
Christopher
Hello Corme,
IN the ACM logging, do you get an exception code for a response?
It could be an error within the function request.
-Kevin
Hi Kevin,
I’m not sure how to extract the exception code from the log, could you please take quick look?
log.txt (31.7 KB)
Thanks again for quick responses.
Christopher
Hello I found that the execption code is as follows 
133 4 0x01 1 .
134 1 0x90 144
135 1 0x04 4 .
136 0 0x4D 77 M
137 1 0xC3 195 Ã
The exception definition is:
04
(04 hex)
Slave Device Failure
An unrecoverable error occurred while the slave was attempting to perform the requested action.
sourece: Exception Codes | Simply Modbus Software
It looks that the slave is error out when you try to write to it. Is that register a read only register on the slave?
Hi Kevin,
This tag in particular is read and write, also it is readable/writeable by any of the 3 levels of access the device possesses.
Should I be using function 0x17?
Kind Regards,
Christopher
Hello,
There isn’t a function code x17
I would try using function code x04 for writing to the registers.
-Kevin
Hi Kevin,
I have it working now.
The issue is that I was not writing the entire address at once;
4288 is 4 registers and I was only writing to 2 which was preventing the value updating.
I successfully used function code 16 (0x10) to write all 4 registers (32bit USER + 32bit PASSWORD) at once.
Thanks for the help and prompt responses.
Kind Regards,
Christopher
Hello,
I am glad you were able to resolve the issue.
-Kevin
