DH+ Comms.

I have a SLC 5/04, Panelview 1000 Standard, Panelview 600 Standard, and a Powerflex 70 networked together. I am also attaching a PC for some cheap data collection using the DDE/OPC server and Excel. I noticed that when I have my PC hooked up and polling some of the read/writes on the panelviews are slightly slower. In fact, I had to change the default timeout for a numeric keypad from 4 secs. to 8 secs. to avoid the Error 308 time out from appearing. This spooked the operators, even though the setpoint they were controlling with the keypad changed. It just took a little longer to get the reply from the PLC. My real question is, if I am seeing a slow down in the network as result of my data colletion system is this having any affect on the processor. I just checked my scan time, with or without my data collection running I am seeing approx. 55 msec. I have optimized everything I can think of in RSLinx. This includes maximum packet size, polling rates, and the amount of nodes I am looking at. I scaled this down from the default Autobrowse to just the two panleviews and the PLC.

Do you have end of the line resistors?

I assume you are using RIO yes?

As GIT said check your network resistors. Are they there? 1 on each end? Only 2 on the network total?

Check the vaule with your DMM.

Is the blue hose connected in a daily chain and not starred anywhere?

Make sure none of the devices is set to be the end node or last node. 20-Comm-R perhaps? Check the dip switches on it.

Try a slower rate.

Check your block transfers. Make sure they coded correctly if they are not they will make a RIO network run like cold syrup.

The block transfers should be fired in a sequence of 1 logical rack at a time and the net rack triggered by the done bit and not just a timer. This is because depending on the amount of words in the transfer and the amount of racks it takes several scans to complete.

Many people put timers in to push the next block transfer if it does not go done or error in a certain amount of time but this needs to be set high 2-3 seconds IMHO.

Make sure block transfer reads and writes are interlocked and not firing at the same time.

Check you 20-comm-r firmware.

If possible it is better to just set everthing to read and as few writes as possible which lowers the overhead.

Check your 5/04 firmware also. You may have the old style roll your own block transfers and they are painful for speed.