Modbus/TCP to Cognex camera

[Controls Guy]

Has anyone been successful talking Modbus to a Cognex camera from a Do-More yet?

I tried it and got only error bits from the box (after the timeout), but I can read from and write to the camera from my HMI or a PC-based Modbus utility.

Don't actually need to talk to the camera, but it's the first time I've had an Insight camera and a Do-More in the same system, so I wanted to try it just because.

[ATU]

I did it with a 260 a couple of years back. They had a memory leak when you use Modbus, every 2 or 3 days of continuous communications would cause the camera to crash. They may have fixed it, but it wasn't a big priority, they were putting their efforts into EIP. Depending on your application it may be ok.  I remember it took a little trial error to figure out the cell addresses. I could send you the program, it might be helpful.

[Controls Guy]

Thank you, I'd appreciate that.  I think my problem is my Do-More program though, or else there's some issue that only exists with both a Do-More and InSight.

I've used Cognex cameras before with EIP, and via Modbus with DL-classics and other Modbus PLC's (not current Cognex firmware), plus I can converse with it fine using PC based masters, both an HMI and Modbus utilities (current firmware).

I guess maybe I should hook up one of those mirroring switches and look at the transactions.  Like I said, I don't need to be able to talk to it from the Do-More, as that's handled by the PC in this app, but I'd like to make sure that I can do it, since I have all the hardware together and hooked up.

[MikeS]

this is one of them situations where a wireshark trace is invaluable. if you can get us a trace of the transactions we can tell you exactly who's complaining about what

[Controls Guy]

They had a memory leak when you use Modbus, every 2 or 3 days of continuous communications would cause the camera to crash.

I think I may be experiencing something like this on the current app.  The PC is talking Modbus to the camera and is generally successful in doing so, but a couple times I've seen the camera lock up and require a power cycle to start acting normal again.  You try connecting to it from ISE and it tries for a while and just never links up.  Today it seems like it occasionally just ignores queries and doesn't return anything after numerous successful transactions, though not locked up this time.  I've used Insight cameras on Modbus before on several projects, as recently as 2012, and never really experienced any issues.  Strange.

The camera with which I'm having this issue is on firmware 4.9.0

[ATU]

My project was mid year 2012 and my customer experienced the same problems. They have to cycle power on the camera's every few days. I could not see any problem in the ladder. I called Cognex, but couldn't get an answer. Tried again later in the day and got hold of an Engineer when the phone techs were at lunch. He told me about the memory leak, but it was a low priority to get it fixed back in 2012.