Identifying coil numbers for modbus

[Batman]

Hi guys,

So I've been tasked with finding out what the coil number is that the source is monitoring and I have captured traffic from a network. I've never heard of a coil number, and after looking through the packet information I'm just completely lost.

Can anyone point me in the right direction of TCP Modbus packet analysis to discover information about modbus traffic?

Yes, I've googled it. The information was a little over my head. I need a teacher! :P

Thanks for your time!

I've attached the captured traffic to this. I've been using wireshark for analysis.

[cooper]

It's all new to me too, but the wikipedia article explains quite a lot. Read that and then use this knowledge to try to make your question more specific.

[Batman]

I figured it out. It was under the Modbus section of the traffic. Coil numbers are the reference numbers.