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Old 11-04-2019, 07:59 PM   #1
sam_sam_sam
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Default Plasma Height Voltage Divider board

I have this problem with our plasma cutting machine
That the plasma head crash into the plate

I have talked to tech support and he was telling to check the voltage divider board which I did

The voltage input to output voltage is 50 to 1 ratio

Which you have the following hook up-s
are as follows

120 volts ac input to power the board

Input voltage from the chopper board about 350 volts

Output to the PLC input card 0 to 5 volts

Well I tested the board at 60 volts input and the output is 1.200

Which is correct

So either the on the PLC input card or the wiring from the Plasma Unit to CNC controller

I just have to make sure that the voltage divider board is getting 120 volts AC
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Last edited by sam_sam_sam; 11-04-2019 at 08:46 PM..
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Old 11-05-2019, 06:18 AM   #2
CapLeaker
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Default Re: Plasma Height Voltage Divider board

I guess, you know that the inverter is o.k. The next step is to figure out if the plasma cutter actually works manually operated.
I do remember someone having had the exact same problem you have. It turned out to be something in the input card. I think you are on the right track, but if the plasma cutter works manually operated, well then you know what direction to go.

Last edited by CapLeaker; 11-05-2019 at 06:22 AM..
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Old 11-05-2019, 08:59 AM   #3
sam_sam_sam
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Default Re: Plasma Height Voltage Divider board

Thanks
I have some things to checking on the input card and make sure that I have 120 volts at the voltage divider board as well

Now we have check to see if I get the same results from what I got on the bench testing

Because at 0 volts input I got 0 volts output or do I get something else
Because at 60 volts input I got 1.200 output or do I get something else

I also have problem with it cutting but the tech and I seem to think that it has be a problem with the gas psi not being right ( no error code comes up )

I also have problem with CNC machine not turning OFF the Height Controller

This machine sometimes is acting like Red Headed Step Child that having a very bad temper tantrum and does not know when to quit ( this a joke that machine manufacturer tech and I have about this machine )

This problem with machine is mild compared to what it can do as far acting up is concerned

Last edited by sam_sam_sam; 11-05-2019 at 09:20 AM..
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Old 11-05-2019, 11:38 AM   #4
redwire
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Default Re: Plasma Height Voltage Divider board

I would check the +/-15V rails to the AD202KN, in case the PSU brick is the problem. Does it work at low line 105VAC and ripple is not present.
I would expect shielded cable for the voltage-divider board output.

Why does this make the head crash into the plate? It's not all stepper motors for height control?
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Old 11-05-2019, 06:53 PM   #5
sam_sam_sam
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Default Re: Plasma Height Voltage Divider board

No it adjusts by a stepper motor

This hole thing has gotten more complicated

I check the input to the PLC controller with diagnostics screen and it was showing the same reading as lab power supply 0 volts at the input and on the diagnostics screen show the same thing at 62 volts at input the diagnostics screen was showing 61.5 to 62.000 very about .500 volts up or down so it pretty close to what it should be

So as far as I am concerned it is working so now to figure out what is causing this problem
The machine manufacturer tech support person was saying that you should check the soldering joints for the control wires from plasma unit to the CNC PLC Input card

I giving this some thought to this idea because he also said that this has been a problem with some of there machines
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Old 11-05-2019, 07:15 PM   #6
sam_sam_sam
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Default Re: Plasma Height Voltage Divider board

Quote:
Originally Posted by redwire View Post
I would check the +/-15V rails to the AD202KN
I give some real though if I see problem with the voltage that being reporting in the diagnostics screen

Quote:
Originally Posted by redwire View Post
AD202KN, in case the PSU brick is the problem. Does it work at low line 105VAC and ripple is not present.
I did check the voltage going to the voltage divider board the voltage was showing 127 volts on volt meter the diagnostics screen was showing 125 volts

If it turns out that the problem is intermittent I will take it back out again do some more of this type of testing on the board again

Quote:
Originally Posted by redwire View Post
I would expect shielded cable for the voltage-divider board output.
No it is only twisted cable

Quote:
Originally Posted by redwire View Post
Why does this make the head crash into the plate?
This is a really good question which I need to get an answer for

Quote:
Originally Posted by redwire View Post
It's not all stepper motors for height control?
The adjustment is done by a stepper motor with a hydraulic push rod ( but I am not sure about how this part works )

Last edited by sam_sam_sam; 11-05-2019 at 07:36 PM..
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Old 11-08-2019, 06:07 PM   #7
sam_sam_sam
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Default Re: Plasma Height Voltage Divider board

Update

They had to much work for this machine for me even being to troubleshoot any thing on it

I might get time next week to work on it

after I put back the PLC in the other machine which I should back either Monday or Tuesday

But I let you all know what I find out when I figure out what wrong with it
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Old Today, 07:32 AM   #8
sam_sam_sam
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Default Re: Plasma Height Voltage Divider board

Update

This Machine is having really bad temper tandem again this time it is blew a fuse on the power distribution board that powers several items in the plasma unit

I going to have to use the light bulb in series instead of the fuse to try to figure out what went wrong with this unit

This is the first time that this fuse has blown
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