Unity Pro, Issue with multiple line IO Scanning for single device.. only Two working ?

[Para]

Hello,

I am using Unity pro V15. I have Quantum CPU 671 and Ethernet NOE 77101 configured. I have configured IO scanning on NOE.

I have attached screenshot for reference.

First 3 devices on IO scanning works fine. I have configured 2 devices (one from line 4 to 10 and second device from line 11 to 19). Both these device models are same.

I have configured first device with multiple IO scanning lines to read total 640 Modbus addresses. Separate lines are created to read data in length of 100 each and last one to read 40. I have set the Unit id to 1 for this device. However, I can get comms with only two IO scanning lines (line 4 and 10). Rest of the IO scanning lines are not communicating.

I have tried changing the unit id of both devices to 255 and got similar result, the comms was established for IO Scanning Line 4. However, instead of line 9, the comms was established for line 10.

I can ping these devices from the network and also can see it is working from its web page. I am also able to Modscan the device.

Could anyone please suggest what can be the issue?

 

[KirkC]

Is this possible? Each line in the IO scanner table opens a separate connection to the Modbus/TCP server you are trying to read from. The server supports a limited number of concurrent connections and you are out of them. Try launching multiple Modscan instances and see how many will poll one of the Modbus/TCP servers.

 

[Para]

Is this possible? Each line in the IO scanner table opens a separate connection to the Modbus/TCP server you are trying to read from. The server supports a limited number of concurrent connections and you are out of them. Try launching multiple Modscan instances and see how many will poll one of the Modbus/TCP servers.

Thank you KirkC. I have tried mod scanning the device multiple times but for some reason it’s not working and after few attempts its crashing. I am getting Error "TCP/IP connection terminated!”. However, In the past, after few attempts, I had been able to Modscan the device. Also, I am still able to ping the device IP.

The IO scanning has worked before for old device with same configuration (only unit ID was different). However the device has been replaced recently with new one. I changed the Unit Id to 1 to match new device in IO scanning and kept rest of the configuration as it is.

 

[Para]

Is this possible? Each line in the IO scanner table opens a separate connection to the Modbus/TCP server you are trying to read from. The server supports a limited number of concurrent connections and you are out of them. Try launching multiple Modscan instances and see how many will poll one of the Modbus/TCP servers.

Hello KirkC. I checked the device manual and it says " The driver is also capable of being accessed by two TCP/IP client devices simultaneously." I think this means I can have only two connection to this device. Do you have any idea what can be the best way to configure IO scanning for this device to read 640 modbus addresses. Thank you.

 

[KirkC]

You will have use READ_VAR and only have one or two reads active at a time.

 

[Para]

You will have use READ_VAR and only have one or two reads active at a time.

Thank you @KirkC. I used Read_Reg function block and kept only one connection active at a time and it seems to work correctly.