I am using a GridConnect Modbus TCP to Serial gateway.
gridconnect.com/industrial-proto … rs232.html
I installed it and it is connected to a Quantum PLC using the serial Modbus(RTU) port on the front of the processor.
I have used ModScan and Kepware both to read from the PLC and they both work flawlessly.
I have a Device configured for it [PLANT] and it connects to the PLC at the driver level ok. (Connects with no errors)
The Modbus Device ID is 3.
in the TAG the address I am referring to is [PLANT]3.HRF756.
I don’t get an error with this address but it never polls the address it just sits there with a green “?” over the TAG and a null for the value.
Any suggestions?
[quote=“rfbuehler”]I am using a GridConnect Modbus TCP to Serial gateway.
gridconnect.com/industrial-proto … rs232.html
I installed it and it is connected to a Quantum PLC using the serial Modbus(RTU) port on the front of the processor.
I have used ModScan and Kepware both to read from the PLC and they both work flawlessly.
I have a Device configured for it [PLANT] and it connects to the PLC at the driver level ok. (Connects with no errors)
The Modbus Device ID is 3.
in the TAG the address I am referring to is [PLANT]3.HRF756.
I don’t get an error with this address but it never polls the address it just sits there with a green “?” over the TAG and a null for the value.
Any suggestions?[/quote]
If possible, try rebooting the gateway. I am on a startup using ModBus TCP to connect directly to Hardy 4050 weigh indicators. I too experineced the green “?” with null values on tags that should have been working.
Rebooting the Gateway resolved this issue, guess the driver was discombobulated somehow.
I rebooted the server and all the points that worked are still good BUT the points talking to [Plant] still have the (green ?) on the tag.
As I said Modscan works just fine. Kepware works fine (on the same machine as the GW. Its just the Ethernet TCP driver that does not work,
When setting up the device you can choose from the Modbus TCP driver and the Modbus RTU over TCP driver - maybe you should try whichever one you aren’t currently using.
It would also probably help if you attached your logs.bin.gz file.
How do I get the log files to upload them?
I zipped the log.bin file, and have attached it.
BTW I tried both the TBP and theRTU over TCP drivers before I posted anything.
Well there’s nothing obvious in the logs, just requests timing out (the device not responding).
Can you call into support and let them poke around? The easiest way to figure out what’s going on will be to just look at the packets Modscan is sending and compare them to the packets Ignition’s Modbus driver is sending and figure out what the difference is. It’s probably something simple like the wrong unit ID or an addressing issue, but there’s only one way to find out… It would be helpful if you had Wireshark installed on whatever machine you’re using modscan and can reach the devices on the network from.
This fix is!!
I am running SQL Gateway 7.5.4.
I downloaded the Modbus V2 drivers for 7.5.11 and it resolved my problem.
It is working fine now.
