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For the debugging it is very convinient, that it is possible to read the Modbus register number not only in the Query but also in the Response in case of FC3 (modbus.regnum16). Is it possible to read like this the FC2 reference number in the Response frame? For now I found, that the reference number (modbus.reference_num) is visible only in Query of FC2. If there is no such function for now, is it possible that modbus community would make such extension of modbus dissector? That would make the use of it much comfortable and I guess more complete, because such feature is already available in case of FC3.

asked 22 May '17, 07:00

Jendker's gravatar image

accept rate: 0%

The dissection of the packed discrete inputs from FC2 could be improved, either by splitting each individual bit out in a manner similar to that for registers, or by displaying the address of the first bit in each byte. The former solution would be preferred as that would allow filtering based on the discret bit address.

To ask for this feature, please raise an entry on the Wireshark Bugzilla (if there isn't one already for this feature), marking it as an enhancement, and if at all possible, attach a capture file with the traffic of interest.

After that, post a comment back here with the number of the bugzilla entry for future reference.

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answered 22 May '17, 08:30

grahamb's gravatar image

grahamb ♦
accept rate: 22%

Thank you @grahamb, the Bug ID is: 13734

I am marking your answer as the accepted as soon as the enhancement is finished.

(23 May '17, 01:58) Jendker
I am marking your answer as the accepted as soon as the enhancement is finished.

That might be quite some time in the future when someone has the time and inclination to make such a change.

(23 May '17, 02:37) grahamb ♦

Than there is no point in keeping this question still open, I am marking as answered.

(23 May '17, 13:09) Jendker

The future has arrived, I found some time last night to make this change.

If you can, please test a nightly build.

(26 May '17, 02:07) grahamb ♦
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question asked: 22 May '17, 07:00

question was seen: 1,013 times

last updated: 26 May '17, 02:07

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