New extrusion line, put in by a contractor in the spring. 1756-L83E with one 1756-EN2T, eleven remote racks hanging off it, eight 1734-AENTR and three 1756-EN2TR racks, plus twelve PowerFlex 755 drives on the same module.
Every morning when the operator hits line start and all the drives come up together, five or six of the racks fault 16#0204 connection timed out, and half the time the line stops on the interlocks. Once it's running it's fine all day.
We changed the cable to rack 7 because the crimp looked rough, and swapped the switch for a spare Stratix 5700, no luck there either. Link light on the EN2T blinks like mad through the start. Is it the switch, or is the EN2T on its way out? Is eleven racks and twelve 755s all coming up in the same second simply more than one EN2T can get through?
What firmware on the EN2T, and which Studio version? Before you swap anything else, open the EN2T's web page, Diagnostics, Ethernet Statistics if I remember right, and read the packets per second with the line running and again during a start.
Studio 5000 v33, EN2T firmware 11 point something. Web page says about 23000 packets per second with the line running. During start-up I saw 26000 and change before the page stopped refreshing, second photo attached. Connections used says 34.
23000 is right under what an EN2T can do. What RPI on the racks?
OG
Checked all eleven. Every rack's on 2 ms, the drives too. The contractor left it that way I guess, we've never touched any of it and nobody here has opened the module properties since spring.
There it is. 2 ms on a discrete rack does nothing for the process and costs about 500 packets a second per rack each way. Eleven racks and twelve drives at 2 ms sits right under the module's 25,000 packets per second rating. At start-up every connection re-opens at once, the drives pile on, and the ones at the back of the queue time out with 0204. Once it's settled you're just under the line.
Set the RPI from what the process needs. Module Properties, Connection tab. 20 ms for a discrete rack, 10 ms where an interlock goes through it, drives at 10 or 20. Longer version with the connection maths: https://plctr.com/utilizing-ethernet-ip-in-plc-communication/
Set the eight 1734 racks to 20 ms, the three 1756 racks to 10 because the guarding goes through them, drives at 10. Did it offline last night and downloaded at 05:00 before the operators came in.
Start-up this morning, zero faults. Web page shows about 3800 packets per second running, and the line's been up all day.
So it was the contractor's 2 ms on everything with the EN2T sat at its limit, nothing more to it, and the RPIs fixed it. What I still don't get is why only the racks faulted and never the drives, they were on the same module at the same 2 ms. Thanks rsdave and billr.
The drives were winning the argument. Every contractor leaves 2 ms in, I've seen it a dozen times.
OG