Cache450 (Customer) asked a question.
My main unit is a p2-550 and I have (2) p2000 remote slave units connected into it through the remote i/o ethernet port. everything works fine like this and has been for a couple years now but the updates from the remote slave units has always been terribly slow... 29-32 seconds between updates. the main unit updates it parameters to the hmi about every 1/2 second which is great but the slaves are a different story. for example, one slave is connected to just a flow meter and it takes a good 30 seconds to get an updated reading from it. I have tried using different cables and hardware for connection between the p2-550 and the p2-rs and nothing helps. I have also had a ticket opened for this as i spoke with someone over the phone about this at AD, we tried changing a few parameters with no luck.
Is this how they are supposed to work? anyone experienced this issue? Am I missing something?
In general, this is not normal. You said updates to the HMI are slow, does this mean that if you open a watch window you only see these values updating at this slow interval? Are all remote updates slow or only a few specific ones?
sorry I worded that a little confusing. I meant to say updates (from the remotes) back the the cpu (rather than the HMI) are slow. also, all parameters from the remotes are slow (30 seconds) to update.
Can you provide a network topology of your system?
Distances between RS and CPU?
Can you provide a wire shark capture of the traffic between cpu and rs units?
I am interested in capturing the traffic with wireshark as you mentioned. if I can figure out how to use it I will get some data
I capture wireshark data using a 'smart switch.' You may not require a smart switch to do this. I do not know.
In the image below, it shows a setup for mirroring physical ethernet ports 19 and 23 bidirectional traffic to port 26 for my pc/wireshark to capture.
Then, in wireshark, I select the pc's ethernet interface (WIRED PORT) as the source and let wireshark do its thing.
I am using wireshark 2.4.4.
The capture looks 'similar to' this
When you stop the capture, you can save the data to one of many capture formats.
AD tech did not specify a capture file format, but I would assume that any format with 'wireshark' and 'pcap' in it should work.
AD should be able to open your file and look at each packet/packet group.
a packet will look 'similar' to
IIRC, there are filters/colum headers to limit what you collect/save, so only the traffic from/to the P2K is included -- in case there is some sensitive traffic on the network.
Be sure to get the blessing of your IT/IS/MIS before you to put wireshark on any network. They may have 'issues' with your ethernet traffic sniffing.
If you can get ahold of a dumb network hub and use it in place of the switch, you should not need to configure it. The hub will allow all of the data on all of the ports instead of routing data like a switch does.
If it was working before for a couple years and now has issues, then it sounds like some sort of hardware failure to me. Either an Ethernet port went bad, or a CPU or remote CPU went bad, or a base has gone bad.
Is it possible for you to run a few tests on the system? Try replacing the program with a blank slate made from a new project. Just make a few lines that basically use an input from each remote base to turn on an internal bit. See if that new program updates quickly or not.
If that did not help, try removing on of the remote CPUs and just use one of them. See if that one responds well or not, then switch and try the other unit by itself and see if the response time is good or not.
"but the updates from the remote slave units has always been terribly slow... 29-32 seconds between updates"
Ah I read that wrong. I thought he meant it was a new issue that they send every 30~ seconds
yes it has always been slow since i put it in a couple years ago.
I have tried connecting only one of the slaves to the cpu, as shown in a diagram i posted below, and it still did not improve 😕