PLC Trainer using Click (need help troubleshooting)

Hello everyone. I'm extremely new to the world of PLCs so keep it in mind when I ask some questions.

I'm trying to build a PLC trainer. I purchased everything I needed and am using Click PLCs, C0-00DD1-D with C0-00AC power supply. I've got six input buttons and a switch, six output indicator lights, an estop button (hardwired), and a power indicator connected to the 24v supply.

I was able to hook up everything, though very messily, and I feel like I've almost got it. All of the inputs are being registered. The only problem I have right now is there is always one output, the light connected to either Y5 or Y6 that doesn't turn on. The program I have in the PLC has all of the outputs turn on unconditionally as a test.

I'm using the wiring diagram found here: http://www.aboutplcs.com/click/hardware/cpu_modules/c0-00dd1-d.html

I've toyed around in that area of the diagram and found that the light that has the connection directly to +24v is the one that is able to turn on, but the other one doesn't.

Is there a wiring mistake I've made that would cause this? I found it to be very confusing wiring that part so 'm not all surprised there's a mistake here. I just can't seem to pick it out. Any help would be appreciated. Thanks!

The diagram shows the flexibility of the outputs. They may drive (sinking) a different voltage than that applied to +V (with common at C3/C4) which powers the internal logic of the output side of the CPU. Remember, the minus side of ALL your output power supplies must connect to C3 and C4.

In practice though you would typically use only one supply. Connect the minus side of a 24VDC power supply to C3 and C4. Connect the plus side to one end of your outout devices and to +V.

I removed the unnecessary connections and followed what you said but still no luck fixing the problem. The light connected to Y6 doesn't work.

Could it just be a defective unit?

In the troubleshooting manual (http://www.automationdirect.com/static/manuals/c0userm/ch6.pdf), it says the voltage between the output and common should be 0. All of them read almost 0 except Y6 which reads 20v... I'll contact Automation Direct and see what they say.

Thanks for the help!

The light connected to Y6 doesn't work.

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As Bernie said before:

Remember, the minus side of ALL your output power supplies must connect to C3 and C4.

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it says the voltage between the output and common should be 0.

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That is from the Output Module Troubleshooting section, and it means that for the voltage to read 0 from an Output terminal to C3 or C4 Common, then that PLC ouput must be turned ON in the program. If the output is ON, the -V is simply switched through to the output terminal, so the difference between any "Y" output and V- should be close to 0 Volts. Of course, for Y6, if C4 is not connected, and you measure across -V and Y6, then the +24 volts will get passed through the load and show up at the Y6 terminal!

That means sending C3 and C4 to the minus side of the supply, right? That's what I have done.

Yes, C3 and C4 should be connected to the - of the same power supply that has its + connected to one side of your Load.

Maybe your light at Y6 has a shot bulb? That does not explain the +20 at the Y6 output. It could be that that output is OFF, or that is burned out and cannot close, which would allow the +20 to travel through the load and show up at the open Y6 terminal.

Test: Disconnect your load from Y6, then measure from your power supply "+" terminal to Y6 (leaving power supply "-" connected to C4 and Y6 turned ON in your PLC program). If it is 0 and not +20 to +26 volts, then the Y6 terminal is off, or burned out and open and not switching the - V.

I tested the bulb, it works.

I did the test you mentioned, and it's reading around 20v between Y6 and the + terminal when Y6 is on. Is that supposed to happen?

Yes, do the test in Post #6 to determine if your Y6 output is burned out. Your output transistor for Y6 could have been overloaded in the past.

For that, if you are capable with electronics, you could unsolder the old transistor and replace it with a new one from Allied or Newark Electronics. Otherwise you will have to get by without the Y6 output. Welcome to the real world of hard knocks!

I did the test you mentioned, and it's reading around 20v between Y6 and the + terminal when Y6 is on. Is that supposed to happen?

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Yes, that means you have a circuit through the output. Now when you turn OFF Y6 in your program, does the voltage between +V and Y6 drop to 0 (with nothing connected to Y6 except a voltmenter)? If so, Y6 is still a good output. If it still shows +20 (still conducting through the Y6 output), then you have a shorted output transistor (on all the time).

Sometimes you can get a shorted transistor to open again if you cool it down by spraying with a can of instant Freeze-It.

Unfortunately, it's still showing 20v.

I contacted Automation Direct and there's a 2-year warranty. Shipping it back to them from Canada will probably be expensive so I'll probably just buy a new one.

Thanks a lot for your help!

I hope I helped some. You can keep the old one until you have time and knowledge to repair it. Or use it for a backup. You still have 6 good outputs.