adccommunitymod (AutomationDirect) asked a question.
Created Date: March 29,2017
Created By: pddubois
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Hello. New to PLCs. The problem: Lose communication between PC and PLC only with solenoid(s) attached or blue screen I'm using the following: Click CO-00DR-D with expansion module C0-08TR (running a drum program) HP laptop with windows 7 AD EM-MG-PGM-CBL cable for communications attached at port 1 Rhino 24V DC power supply Koyo driver Click version 2.0 and a few 24volt DC solenoids There is no problem with the following: 1.) Establishing communication to the PLC 2.) sending a program to the PLC 3.) reading the PLC program upon connection 4.) running the PLC program indefinitely when there is no solenoid attached As soon as I attach a solenoid and run the program I receive the "lost comm " notice in the click software or the pc blue screens. The PLC continues to cycle through the program. I have checked: grounding, disabled the USB power suspend, tried different usb ports, reboots, uninstalled and reinstalled both the driver and software (without antivirus running), I am running without antivirus (essentially shutoff anything in windows or on the pc that I can). Sometimes I can reestablish communications (by killing the "KE " Process) but most times I need to unplug the USB and reinsert. I have also used the USB ports for other things without issues so I will assume they are ok. So the last few things to try or look at are the Prolific driver, another PC and possibly a bad AD cable. Are there any other suggestions or obvious potential items I can look at? I'm sure I am overlooking something. Thanks in advance for any help provided!
Created Date: March 29,2017
Created by: pddubois
Hello. New to PLCs.
The problem: Lose communication between PC and PLC only with solenoid(s) attached or blue screen
I'm using the following:
Click CO-00DR-D with expansion module C0-08TR (running a drum program)
HP laptop with windows 7
AD EM-MG-PGM-CBL cable for communications attached at port 1
Rhino 24V DC power supply
Koyo driver
Click version 2.0
and a few 24volt DC solenoids
There is no problem with the following:
1.) Establishing communication to the PLC
2.) sending a program to the PLC
3.) reading the PLC program upon connection
4.) running the PLC program indefinitely when there is no solenoid attached
As soon as I attach a solenoid and run the program I receive the "lost comm " notice in the click software or the pc blue screens. The PLC continues to cycle through the program.
I have checked: grounding, disabled the USB power suspend, tried different usb ports, reboots, uninstalled and reinstalled both the driver and software (without antivirus running), I am running without antivirus (essentially shutoff anything in windows or on the pc that I can).
Sometimes I can reestablish communications (by killing the "KE " Process) but most times I need to unplug the USB and reinsert. I have also used the USB ports for other things without issues so I will assume they are ok.
So the last few things to try or look at are the Prolific driver, another PC and possibly a bad AD cable. Are there any other suggestions or obvious potential items I can look at? I'm sure I am overlooking something.
Thanks in advance for any help provided!
Created Date: March 29,2017
Created by: scott.lawrence
Not familiar w/ Clicks, but do you have the PLC & solenoids sharing the same source (Rhino)?
Created Date: March 29,2017
Created by: pddubois
Yes. The C0-OODR-D is a "8DC input/6 Relay output micro PLC ". Solenoid(s) are connected on output contacts activated by drum programming sequence. Source is 24volt/2.5 amp total. Solenoids are 24 volt/0.4amp max draw, each. Drum sequence has no more than 3 solenoids activated at a time - should have enough current. This occurs with one solenoid attached.
Created Date: March 29,2017
Created by: pddubois
Found a work around but not sure why it is needed. Installed a powered USB port between the laptop and the AD EA-MG-PGM-CBL cable. To this point have cycled through a seven step drum test sequence without blue screen or "lost comm " message.
Created Date: March 29,2017
Created by: kewakl
You mentioned a laptop. Does this happen if the laptop is NOT connected to the AC charge adapter? -- i.e floating laptop.
btw, 400mA does not consider the inrush, maybe the inrush is causing an IR voltage on the GND or ZERO volt line.
Pictures of your wiring if you can. Maybe wiring diagram. It does sound like a grounding issue.
Created Date: March 29,2017
Created by: pddubois
I did not try the floating laptop. Would a floating laptop be a better test?
Per the solenoid mfg documentation the inrush voltage is nonexistent for these DC valves.
I will try to upload an image/schematic.
One more thing - the "lost comm " message or pc crash occurs after the power to the solenoid is cycled off, not on activation.
Created Date: March 29,2017
Created by: Bering C Sparky
From page 33 in your click manual.
It is strongly recommended that the power source for the logic side be separate from the power source for the field side to help eliminate possible electrical noise
Created Date: March 29,2017
Created by: pddubois
@ kewald and Bering - thank you for your help! Are "grounding issues " and "possible electrical noise " separate and distinct differences? Or can I solve the possible electrical noise issue with adequate and sufficient grounding? I think I know the answer but "I think " isn't working well on this project.
Created Date: March 29,2017
Created by: Brick_Whisperer
Add suppression diodes to your solenoids (and any inductive loads).
Created Date: March 29,2017
Created by: Bering C Sparky
One more thing - the "lost comm " message or pc crash occurs after the power to the solenoid is cycled off, not on activation.
I had a feeling you were going to say this.
This is why using freewheeling diodes across your DC solenoids is a good practice.
When you open the circuit to your solenoid, as the magnetic field around the coil begins to collapse your voltage can spike to many times greater than the actual operating voltage of the coil.
I will usually install an interposing relay between the PLC output and the inductive load also.
It is much easier and cheaper to change out a relay than to change a I/O card or in your case an entire brick plc once your relay contacts arc out and weld together from the fly back voltage you are receiving from these inductive devices.
BCS