I have used this utility to, and can vouch that it works well. It also passed our corporate antivirus / application scanner.

I've got a couple other free / open-source modbus scanning utilities installed, but I think this one was my favourite to use.

 

Nice, I'll have to try this out next time I have a modbus issue. Modscan is great, but it's stupidly expensive for what it is. At this point it should be freeware

 

Modscan is great, but it's stupidly expensive for what it is.

It's a reusable tool without a subscription and it's made in America by some guy that picked up the phone when I called him to expedite a sale. Been available for literal decades to become a industry standard. I think I've bought it about three times now in different employers / roles. Worth it.

 

Ditto.

I must own a dozen or more licenses for Modbus Tools poll/slave over the years.

Maybe the free stuff works. I know the minor cost I have in paid software works from user input to wire. When I needed such tools, there was no open source alternative. After investing the first copy, learning exactly how it works...I would still just buy another license vs investing the time sorting out exactly how an unknown OSS tool works. Reset my Modbus voyage today, I would certainly give the OSS tools the first look.

We got some big multi-vendor modbus job to pull off yet $100 software to save 100x labor isn't in the budget? Best of luck if that's your SOP.

If you take on the OSS option and invest the time to sort out exactly how your input is transmitted on the wire to sanity check everything and review it, hats off!