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Jazz R31

Please help Troubleshoot My First Project

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Hello,

I am new to PLCs and have no training in the feild what so ever. However, I have a project set up and need help to troubleshoot the issues with respect to my wiring job or the PLC logic.

I have attached a detailed project description (sensor and solenoid, ladder logic, and wiring diagram) and my questions for people to clearly understand my project and questions that I have not learned the anwers for yet.

I look forward to learning more.

Thank you

PLC Questions.docx

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Welcome to the form!

Nice job on providing most of the details on your project.

First quick tip, save your word document as a .DOC instead of a .DOCX. There are many out there that do not use the newest version of word yet and will be unable to view your file.

***************************************************************************

"Is there a concern having two separate power supplies?"

No concern, it is actually better to do it this way. It will help isolate the kickback from your inductive loads from wroking its way into the controller.

In addition, you should use snubbers on your solenoid coils to help prolong the life of your PLC outputs.

You may also consider fusing the outputs, or at least the power feed to the outputs so that a bad ciol or short doesn't blow your output/outputs.

**********************************************************************************

"Why does the PLC logic remain at 1 when the sensor state changes when sensing a target?"

Your wiring diagram does not make sense. It shows all of your input tied "ON" all the time. It shows all of your prox swtiches shorted.

The browns and blacks shoudl not be tied together. Each black wire should come back to a separate input. Each Blue wire should go to 24V common. Each brown wire should go to +24VDC.

*************************************************************************************

"During debugging mode, the Output logic value is "1" when the solenoid is in use. I cannot switch the state to 0 using the reset button in the PLC software"

"Why doesn’t the solenoid engage when I manually change the state of the solenoid in the logic?"

Because your program logic is overwriting it.

You are using "output energize" instuctions. They are updated every scan based on the true or false condition of the logic preceeding it..

************************************************************************************************************************

"When I toggle the state of the unused solenoid, I can hear the relay inside the PLC make a click sound confirming that the internal relay is functioning"

"Is this directly related to a wiring problem with the input and output wiring?"

Your wiring diagram does not indicate you are providing power to your relay outputs.

*********************************************************************************************************************

You should provide a description of what you are actually trying to do with your application. It is difficult to comment on your ladder program without the context of knowing what it is supposed to be controlling.

D

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Welcome to the form!

Nice job on providing most of the details on your project.

First quick tip, save your word document as a .DOC instead of a .DOCX. There are many out there that do not use the newest version of word yet and will be unable to view your file.

***************************************************************************

"Is there a concern having two separate power supplies?"

No concern, it is actually better to do it this way. It will help isolate the kickback from your inductive loads from wroking its way into the controller.

In addition, you should use snubbers on your solenoid coils to help prolong the life of your PLC outputs.

You may also consider fusing the outputs, or at least the power feed to the outputs so that a bad ciol or short doesn't blow your output/outputs.

**********************************************************************************

"Why does the PLC logic remain at 1 when the sensor state changes when sensing a target?"

Your wiring diagram does not make sense. It shows all of your input tied "ON" all the time. It shows all of your prox swtiches shorted.

The browns and blacks shoudl not be tied together. Each black wire should come back to a separate input. Each Blue wire should go to 24V common. Each brown wire should go to +24VDC.

*************************************************************************************

"During debugging mode, the Output logic value is "1" when the solenoid is in use. I cannot switch the state to 0 using the reset button in the PLC software"

"Why doesn’t the solenoid engage when I manually change the state of the solenoid in the logic?"

Because your program logic is overwriting it.

You are using "output energize" instuctions. They are updated every scan based on the true or false condition of the logic preceeding it..

************************************************************************************************************************

"When I toggle the state of the unused solenoid, I can hear the relay inside the PLC make a click sound confirming that the internal relay is functioning"

"Is this directly related to a wiring problem with the input and output wiring?"

Your wiring diagram does not indicate you are providing power to your relay outputs.

*********************************************************************************************************************

You should provide a description of what you are actually trying to do with your application. It is difficult to comment on your ladder program without the context of knowing what it is supposed to be controlling.

D

----------------------------------------------

Thanks for your help D, I made the sensor and solenoid wire changes as you pointed out and I reattached the wire schematic for your review.

The sensors now show they are at a closed or open state ~4 or 20 volts. The weird thing is when a target is sensed the LED lights up but no change in voltage, the voltage starts at 4 VDC and does not jump to 20 VDC.

Secondly, the solenoids still do not turn on when I change their state by toggling the output while in the debugging mode. Yet when I check continuity from the V+ to the solenoid output, the volt meter rings off each time I change the output state. So that tells me the PLC relay switch is making, but there still must be a short to solenoid. (I don't get it).

The logic I attached before was to fill a tank based on two levels sensors low and high level. The low level sensor will turn on valve A & B and fill the tank until the high level sensor is true.

Any other pointers here would be greatly appreciated.

PLC Questions.doc

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----------------------------------------------

Thanks for your help D, I made the sensor and solenoid wire changes as you pointed out and I reattached the wire schematic for your review.

The sensors now show they are at a closed or open state ~4 or 20 volts. The weird thing is when a target is sensed the LED lights up but no change in voltage, the voltage starts at 4 VDC and does not jump to 20 VDC.

Secondly, the solenoids still do not turn on when I change their state by toggling the output while in the debugging mode. Yet when I check continuity from the V+ to the solenoid output, the volt meter rings off each time I change the output state. So that tells me the PLC relay switch is making, but there still must be a short to solenoid. (I don't get it).

The logic I attached before was to fill a tank based on two levels sensors low and high level. The low level sensor will turn on valve A & B and fill the tank until the high level sensor is true.

Any other pointers here would be greatly appreciated.

I was unable to open the new document

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Hi there,

I have taken the liberty of making a rework of your

wiring diagram. The only thing I did not show is the positive connection

to your level probe controls (but you know that they are there). I

stripped off anything about our company on the letterhead (I am not trying to

advertise :rolleyes:). If I interpreted your second drawing correctly, the solenoids are not connected correctly, so try this out.

But if this is helpful to you let me know here in the forums and I can email you a copy of the autocad drawing if you want it for your files.

Thanks

Keith

LEVEL CONTROL PROGRAM Layout1 (1).pdf

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Hello Keith,

Your drawing is very helpful and the solenoids work great now. Thanks!

The level senosrs are not working as I expect them to. They are a three wire capacitive sensor and I have all four sensor's blue wire connected to the common, the browns are all connected to the V+ and the black wires all individually land on an input. When a target is sesnsed, the LED lights up on the back of the sensor, but the PLC does not recognize the change of state. Is this logic related or still a wiring issue? Can anyone share a simple logic that will open a solenoid based on low level and then shut off the solenod after the high level sensor senses liquid?

Thanks so much!

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First of all, are your capacitive sensors PNP or NPN output? They need to match the input type of the PLC, which is looking for a PNP sensor. You can verify this by putting a voltmeter on the input and verifying that it goes to about 24V when the LED is on.

Two sensor level control, assuming normally open sensors:

level control.jpg

Joe T.

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Hi Joe,

My sensors are Normally Open, NPN, and the Jazz manual confirms that it will accept either NPN or PNP. I wired the Blue wires to common, the Brown to positive, and the Black wires to the inputs. I test the voltage at the input and find ~22 volts DC with no target sensed and the LED off. When I place a target infront of the sensor, the LED light turns on and the voltage at the input remain at ~22VDC.

I would expect that the voltage at the black input wires should be low with no sensing and high with sensing.

Thank you for the logic for level control. I hope to put it to work once my sensor issue is straightened out.

Does the Jazz 10-11-R31 provide a way to set a lead and lag logic control?

Thanks Again!

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I would test your sensor with the black wire disconnected from the PLC input. Based on the circuit diagram provided in your first post, I would expect the output of the NPN sensor to be High for the "no sensing", and Low for the "sensing" state.

Also check the wiring of the input commons on the Jazz, see below from the installation guide.

post-16-052543800 1322437567_thumb.gif

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Based on your original diagram, as a result of the miswiring is it very plausible your sensor outputs were damaged. Pay close attention to Simons & WalkerOKs diagram, as it shows that for an NPN sensor you need to bring +24v to the input commons.

Also, keep in mind the real difference between and NPN and PNP sensor. A common misconception is that with NPN you get 0v for ON and +V for OFF, and for PNP you get +24V for ON and 0V for off. In reality, for a PNP sensor you get +V for ON and "Open Connection" for OFF. By the same token for an NPN sensor you get 0V for ON and "Open Connection" for OFF. In this fashion, you need to be careful how you measure the output of an NPN sensor in order to truly understand its state. You will get different readings based on whether your sensors signal wire is unhooked or is still connected to the input. This is because the input device is normally either "pulling up" or "pulling down" the voltage across internal resistors. In short, the sensor provides the ON voltage state, and the input provides the OFF voltage state.

Just to make certain you have your inputs "pulled up" correctly, touch 0V to a spare input and verify that you see the state of that input change.

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Hello All,

Thanks for getting me on the right track, my sensors were damaged from me miss wiring them in the beginning. I replaced them all with new sensors($$) and wired them correctly the first time and they all work the way they should.

I am now working to solve some of my logic challenges.

Thanks again!

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