RS485 (Modbus RTU) monitor advice sought

I am in the market for a hardware/software toolset to be able to monitor RS485 traffic in a Modbus RTU (RS485) setup which involves one master and two slaves.
Specifically, I am trying to figure out the delay settings for the master (a 1769-SM2) to talk to the slaves.
I see that COMMFRONT has a rig that will intercept the signals, and show the times.
Are there others that I haven't found yet?
Decoding the MODBUS, while nice, is not required, as the commands are manually generated at this time.

Google found this one. I'm not sure if it's what you are looking for, but here it is anyway.

http://www.fte.com/products/SerialAnalyzers.aspx

This looks a bit expensive but it seems to have the features you want.

Apparently great minds think alike.

Triangle Of Truth is active here, as in life.
Good Fast or Cheap. Pick the two you want, 'cause you can't have all three...not ever.

Mickey said:

Google found this one. I'm not sure if it's what you are looking for, but here it is anyway.

http://www.fte.com/products/SerialAnalyzers.aspx

Click to expand...

Thanks.
Bernie and Jeff.. are right. A bit pricey for a one-use thing. Now, if I was developing a product, or wanted to show evidence to my potential cusotmers that I had, in fact, interfaced my equipment to Modbus with success, I'd have to have this.

Hint, hint, to people engineering equipment....

Comment in general:

"Protocol analyzers" tend to display interpreted bits/bytes/ in various formats.

The assumption is that the electrical signals are clean and that there's no false signal due to noise.

Windows based protocol analyzers tend not to be oscillscope style displays, with actual waveforms, but rather the interpreted data as ones and zeros.

Specific to SerialTest sold by Frontline Test:

Does the analyzer show time domain data in a resolution sufficient to solve your problem?

Not just transmission A, then reply transmission B, but transmission A, some time gap of x uS or y mS, then reply transmission B? I'm asking, I don't know one way or another.

Other products:
1) Software Innovations
Check out the SI-Scope
http://rs232-serial-communications.com/serial-protocol-analyzer.htm
"All RS232 data, error conditions, and signal changes are recorded and time stamped at the interrupt
level by SI-SCOPE'S PMC device drivers. SI-SCOPE'S interrupt driven design guarantees that the
sequence of events are correctly maintained and the time between the events is accurately measured."

2) IfTools
https://iftools.com/start/index.en.php (note that the oscilloscope display image is not representative of its performance displays, which are non-oscillographic protocol analyzer displays

3) 232-Analyzer
http://www.232analyzer.com/232default.htm

This may be of some interest:
http://www.control.com/thread/1256486484

Also, if you are just trying to work our some timings and not worried about interpreting the bits, you may just want to hook up a regular scope and see what you see... The baud setting should give you a good indication of the bit timing. However, I have never tried this myself so YMMV as the saying goes.

I think Ken Roach did a write up 1 time about using a scope to troubleshoot.
I can't find the link right now if I find it I'll post it.

http://www.plctalk.net/qanda/showthread.php?t=35172
http://www.plctalk.net/qanda/showthread.php?t=51914
OK so I found some of them.

Frontline Test Equipment's suite is serious professional-grade stuff. I've solved very tricky inter-byte timing problems using it in conjunction with a CleverScope (which can decode UART signals). If you do a lot of serial analysis or there's a lot of money riding on your work, FTE is what you want in your toolkit.

Danw, thanks for posting those links, especially to the IFTOOLS product. That's going to get a close look later.

Both Frontline Test Equipment and Software Innovations base their serial intercept boxes on a reference design that is built by Stratus Engineering, who also sell their own standard version. I had one of the original Stratus EZ-taps before I had the FTE version (which has customized firmware to work with SerialTest and NetDecoder directly).

If I was in jdbrandt's shoes, I would get the Stratus Engineering "Versa-Tap". The simple utility that comes with it, or the use of DockLight shareware is a very powerful way to examine RS-485 traffic with very precise time stamping.

Thanks for finding those old threads, Jeff. I'd forgotten about most of that stuff !

If the versa tap is as good as the eztap than buy it. I took Ken's advice and got the eztap and docklight. If it is the serial application I'm covered.
I did a bunch of ascii over 232 and they were great. My customer like it so much they bought a set as well.

In the end, I went with 232analyser It worked for what I needed, and the setup was painless.
There are a few free-ware solutions, as well, and I used Chipkin for its 'discover' feature....kind of like IPScan for Modbus.

Versa-Tap, Docklight Scripting and Modbus

Sorry to dredge up an old thread....

I'm troubleshooting a Modbus problem that just started happening here. I have a Versa-Tap, an EZ-Tap, EZ-View and a licensed version of Docklight Scripting.

I previously used FTE's Serial Test, but since we couldn't get the funds for it here, I decided to try the Stratus Engineering solution since we had funds for that.

I'm able to capture the data coming in on the RS-485 lines (two line), but there doesn't appear to be any way to decode the data in EZ-View (which I expected) or Docklight Scripting (which I didn't expect).

There is an example script which will add the checksum to a message that you send, but since I'm only monitoring data, I just want the incoming data to be broken out into the modbus packets like Serial Test does.

Does anyone know of a way to do this? I think that I could probably write some sort of script myself, but I assumed that paying for Docklight Scripting would include this functionality....

Too bad I can't use the Versa-Tap with Serial Test.

Thanks in advance.

I haven't tried exactly what you're looking for, but agree that on-the-fly decoding is where FTE earns their money.

I think SerialTest does work with the FTE edition of the VersaTap; there's custom firmware in that one. My VersaTap and EZ-Tap are ordinary stock units from Stratus.

One method you might use until you develop the ability to decode Modbus in raw hex on sight is the handy (and free of charge) Chipkin Automation Systems Modbus RTU Parser utility. You give it a string of hex, it returns a plain-English Modbus command description.

http://www.chipkin.com/technical-resources/cas-modbus-rtu-parser/