VFD 1305-BA09A via controlNet

[Guest Darth]

need your expertise on this. here's the communication setup. (PLC 5/40C processor) to (controlNet adapter 1794-ACNIS with flex i/o 1203-FMI scanport module) and to (VFD 1305-BA09A drive). there were times that the signal is lost to VFD without fault indication. it just stop and run on its own. i've change VFD and scanport but still the problem occurs. any idea what causes this.

[Eddie Willers 2]

You're going to have to be more clear. Does the drive stop and start when you do not think you are commanding it to do so ? When you say "without fault indication" do you mean that there is no F10 Serial Fault indicated by the 1305 drive, or that the Connection Status bits in the PLC-5C never change ? You mentioned a PLC-5C controller. Is this really a ControlNet Phase 1.25 controller (about seven years old !) or a newer PLC-5C15 Phase 1.5 controller ? I'm not sure how you can say that communications is lost to the drive, if you also say there is no indication of a fault. The drive stopping and starting is more likely an indication of an input to the drive that you do not anticipate, rather than an erroneous command of the drive.

[Guest Darth]

processor is PLC-5C phase 1.25. while the problem occurs, i monitor the speed ref. and logic command to drive (ie. stop, start bit) from plc and found that the command is steady. but the vfd stop then run on its own, so i assume that signal to vfd was lost for some reason. i've checked also the grounding and cable termination but the problem still occurs. need ur advice and thank for the reply.

[Eddie Willers 2]

Assume nothing, young Skywalker. There are several ways the PLC-5C and the 1305 drive could be losing communications. 1.) The ControlNet logical connection between the PLC-5 and the 1794-ACN adapter could be disconnecting and reconnecting. I don't remember much about the Phase 1.25 controllers, but there should be a Connection Status entry for the I/O Connection between the PLC-5 and the 1794-ACN adapter. Monitoring this memory location for connection status will tell you if you should investigate the physical ControlNet cable system further. 2.) The SCANport connection between the 1794-FM1 and 1305 drive could be connecting and disconnecting. Usually when the SCANport connection fails, an A-B drive faults with F10 -Serial Fault. You should check the fault buffer for that error code. It's possible to program the drive to not fault on SCANport interruption; you should make sure the drive DOES fault on SCANport disconnection because that will help you figure out where the problem lies. 3. The SCANport device (1203-FM1) could be sending incorrect data to the 1305 drive. Is it possible that the output words you've defined for the 1305 drive on ControlNet are being used elsewhere in the program without your knowledge ? It would also be useful to know if this problem cropped up recently, if any changes were made to the PLC program or network configuration, or if this is a new system that is using old hardware.

[Guest Darth]

thanks for the info skywalker..