Under review

Modbus limit

Kristián Vojčík 2 years ago in Devices / Modbus updated 2 years ago 4

Hello. I am facing strange behaviour of Modbus device. I am sending about 150 values thru Modbs and after test I got an error Device is not connected. I see it been connected and immediately disconnected. So I try it with fewer values and it works. After many tries I got on point where it works but when I add one more Duble value it stop working. So I start wondering is there any limit for Modbus point like how many you can add under one Modbus device? I ended up utilising two Modbus devices so it works. Same issue on Jigsaw and Windows Server.

Under review


seems you've hit the limitation of modbus addresses used. This could be the driver itself or even the modbus dongle or the modbus interface you're using but it seems that the number you reached is the maximum that can be used.

Best regard.

But it is issue on Jigsaw side or the other because with PLC only I have tested in couple of hundred addresses and it works no problem, and also Modbus run over TCP IP so there is no dongle. It is possible if there is some limitation in Jigsaw it could be fix in some update perhaps?

We'll do some testing to see if we can determinate the issue. You mentioned this issue on jigsaw and windows server which was a bit confusing. To summ up, when you reach a certain number of addresses on Jigsaw, the driver starts reconnecting? Does the communication go trough at all? Can you send/get any values or is it constantly reconnecting?

Best regards.

Yes I reach point where I can add boolean but not double and when I add one communication stop working all together no sending no receiving it says connected and half second later it says disconnected and it try reconnect but no luck there. If it could help I can send you whole configuration if you want look at it.