Please be gentle as I am rather new to this..
I am doing data collection from 6 PLCs (5 SLC5/03,1 SLC5/04) via OPC. The OPC server is RSLinx and the data is being collected with an update interval of 1 second. The PLCs are on ethernet via an AB NetENI device. I am collecting approximately 30 data points per PLC (most data points are a word).
The configuration works well 90% of the time, providing 1 second updates of the data, But occasionally (lets say anywhere from 10 seconds to 2 minutes, every 1-2 hours) we get bunch of bad data (the OPC data Quality indicator is "Bad" and the values are all 0). Upon looking at the communication events logged by RSLinx, I found the following two different errors for many different data points....
MYSAMPLENET\111.11.11.11 : N99:0 : 08/10/06 - 13:25:28 : 05h
Items: N99:0, N99:1, N99:10, N99:11, N99:12, N99:14, N99:2, N99:3, N99:4, N99:5, N99:6, N99:7, N99:8, N99:9
Type: READ
Mfg: Allen-Bradley
PlcType: SLC-503+
Desc: Local Error: TimeOut
The application layer time out while waiting for a response.
Number of occurrences: 670
Last Error occurred: 08/16/06 - 10:41:54
MYSAMPLENET\111.11.11.12 : N99:0 : 08/10/06 - 15:15:11 : 02h
Items: N99:0, N99:1, N99:10, N99:11, N99:12, N99:14, N99:2, N99:3, N99:4, N99:5, N99:6, N99:7, N99:8, N99:9
Type: READ
Mfg: Allen-Bradley
PlcType: SLC-503+
Desc: Local Error: No Ack Received!
The remote station specified does not acknowledge the message. Check if the destination station is on the Data Highway/PCL link.
Number of occurrences: 504
Last Error occurred: 08/16/06 - 10:38:07
As an aside, we tried testing with Kepware OPC server and didn't get any Bad data messages from the OPC server, but we would only get updates every 4 seconds (despite the 1 second update rate) if we collected from all 6 PLCs.
Does anyone have any ideas as to what might be causing such behaviour?
Thanks very much.
I am doing data collection from 6 PLCs (5 SLC5/03,1 SLC5/04) via OPC. The OPC server is RSLinx and the data is being collected with an update interval of 1 second. The PLCs are on ethernet via an AB NetENI device. I am collecting approximately 30 data points per PLC (most data points are a word).
The configuration works well 90% of the time, providing 1 second updates of the data, But occasionally (lets say anywhere from 10 seconds to 2 minutes, every 1-2 hours) we get bunch of bad data (the OPC data Quality indicator is "Bad" and the values are all 0). Upon looking at the communication events logged by RSLinx, I found the following two different errors for many different data points....
MYSAMPLENET\111.11.11.11 : N99:0 : 08/10/06 - 13:25:28 : 05h
Items: N99:0, N99:1, N99:10, N99:11, N99:12, N99:14, N99:2, N99:3, N99:4, N99:5, N99:6, N99:7, N99:8, N99:9
Type: READ
Mfg: Allen-Bradley
PlcType: SLC-503+
Desc: Local Error: TimeOut
The application layer time out while waiting for a response.
Number of occurrences: 670
Last Error occurred: 08/16/06 - 10:41:54
MYSAMPLENET\111.11.11.12 : N99:0 : 08/10/06 - 15:15:11 : 02h
Items: N99:0, N99:1, N99:10, N99:11, N99:12, N99:14, N99:2, N99:3, N99:4, N99:5, N99:6, N99:7, N99:8, N99:9
Type: READ
Mfg: Allen-Bradley
PlcType: SLC-503+
Desc: Local Error: No Ack Received!
The remote station specified does not acknowledge the message. Check if the destination station is on the Data Highway/PCL link.
Number of occurrences: 504
Last Error occurred: 08/16/06 - 10:38:07
As an aside, we tried testing with Kepware OPC server and didn't get any Bad data messages from the OPC server, but we would only get updates every 4 seconds (despite the 1 second update rate) if we collected from all 6 PLCs.
Does anyone have any ideas as to what might be causing such behaviour?
Thanks very much.