Plasma Height Voltage Divider board

[sam_sam_sam]

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

[CapLeaker]

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.

[sam_sam_sam]

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

[redwire]

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?

[sam_sam_sam]

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

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

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

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

I would expect shielded cable for the voltage-divider board output.

No it is only twisted cable

Why does this make the head crash into the plate?

This is a really good question which I need to get an answer for

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 )

[sam_sam_sam]

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

[sam_sam_sam]

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

[redwire]

Re: Plasma Height Voltage Divider board

I keep thinking the site has a power problem, if it blows power supplies and fuses on equipment. This is when I look for an open neutral or bad ground at the distribution transformer. Call the utility and get them to check.

If the plasma power dist board has model numbers, or part numbers, or pics. A power surge takes out the SMPS primary-side.

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update
I found out what happened to this unit and why the fuse blew on the power supply board
The power board in the metering console unit the screws had came loose holding the power supply board but because the way it is mounted on the machine it hard to see it

I used the light bulb instead of the 6 amp fuse and power up each unit one at a time and when I got to the metering console then the light went very bright and and the LED power light on this unit was pulsating and not on steady like it should be

One note this is with the 6 amp fuse back on the power supply board

But there is a problem with the main power supply board that the machine is reporting that the 120 volts is NOT present but it does have 120 volts AC

So now I have to take this board out and see what happen to it

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update
The problem looks like it is in the communication board that senses the voltage off of the power board

But the manual seems to be wrong about how to check the functionality of it
Because it says that the voltage on this connector should be 120 volts X ( 2 ) AC but this is a switching power supply board but the connector in question has 24 volts DC and a 5 volts DC that the four wires that are connected to board one note the board really has three voltages it also has a 15 volt DC but is not being used

One other note

This plasma machine has a lot of switching power supply boards in it and has lot of communication board in it

Gas console ( 1 ) switching—> power supply board ( 1 ) communication board
Metering console ( 1 ) switching—> power supply board ( 1 ) communication board
Cooling unit ( 1 ) switching power supply board ( 1 ) communication board
Chopper main board units ( 4 ) / main transformer power board / main communication board

I will have to call tech support tomorrow and get the right information about how to check this board

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update

The problem was on the communication board power supply connector
The connectors on the low voltage 24 v , -15 v , +15 volts and 5 v to the communication boards these connectors give problems every so often

This is why it not reporting the 120 volts AC input correctly

But I did check the switching power supply and the power supply with a transformer power supply regulators to make sure that I had the right voltages coming out of each regular

So the plasma machine is back up and running again

Thanks goodness for this one less headache to worry about

The machine is done with it temper tantrum for the time being

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update

So a few days have gone by

The machine is rocking and roll-en again with out any real problems

The hole problem started with the plasma machine not wanting to cut through the thickness of plate that we had on the plasma table and went down hill from there as I talked about earlier

The problem with the plasma machine not wanting to cut through the plate was there two plastic hoses ( one is blue and the other one is black) that are from the metering console to the plasma head the black one had a crack in it that has a pin hole in the crack this is the first time I have had this problem

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

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

Here is what I found out about this problem because the plasma head did not have the correct gas combination it was causing the voltage divider board not to get the right voltage for the height control sensor to report the information to the CNC controller to work correctly

So if your gas combination is not correct then your voltage sensor will not report the right voltage which causes the height controller to try to get to the right voltage so if it can not get the right voltage it crashes the plasma head to the plate which stops the CNC controller and go into an error

But you should be able to use the plasma machine with out the height controller being turned ON but unless you follow the right steps you think you have it disable but the reality is that have not disabled it even though the CNC controller shows that it has been see what problem with this was —>

But the problem with the height controller can not be turned OFF unless you have the plasma machine controller powered ON to do this step

Now you can turn the CNC controller height controller off and shows that it is in inactive state but it is not the case unless you have the plasma machine unit powered ON

Just like you can not turn off the Plasma machine in the CNC controller start up - line up - diagnostic testing
unless you have plasma unit turned ON first then you can take it out of the startup-lineup routine

This is some real shit that the machine manufacturer would have their machine programmed setup this way

This is not the only thing with their machine programming it has other issues as well which I have had to deal with in the past

There is a moral story to the art of troubleshooting
The first thing to do is understand how each process works and in what order steps must be in
What has to happen when and how they are supposed to work together for the process to work correctly

Part of my problem was that I did not fully understand the process exactly worked so I was partly handicap because of this but I have was to get the right information to get to where I can figure out what wrong with the unit in question

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

There is a moral story to the art of troubleshooting
The first thing to do is understand how each process works and in what order steps must be in
What has to happen when and how they are supposed to work together for the process to work correctly

Update

Now the plasma torch unit took another shift but this time it will not do the dig

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update

This time the plasma torch unit will not go through the self test it stops at the purge part of the test

I talked to tech support about this problem and there thinking is that I do not have 5 volts to optic sensors on the solenoid valve power supply board that is to a ribbon cable or something is pulling down the 5 volt supply to this portion of the board

So now I have to do some testing on these three boards
Solenoid power supply board
Switching Power supply board
CAN communicate board that the ribbon cable goes to the solenoid power supply board
The ribbon cable it self

Because I am not seeing the LED lights turn on for which solenoid is being turn ON so I have narrow it down to part of the system

[sam_sam_sam]

Re: Plasma Height Voltage Divider board

Update

The solenoid board is working okay nothing is pulling down the 5 volt rail

I still have to check the switching power supply board

I had machine operator rip off the plate pusher assembly which broke the cylinder thread end where the pusher assembly bolts too and to top it off the plate sensor went bad saying that there is a plate when there is no plate there

I had a hydraulic machine shop repair the cylinder and got a new plate sensor and now the machine back up running with the OXC torch again until something else happens

So I have not had time to work on the plasma problem maybe next week I might have some time to work on it because now they need the plasma unit back up running very soon

So we will see how this play out

One note this something I stumbled on about this machine and it not wanting to turn off the plasma torch unit if it is reporting and error if you remove the CNC communication cable between CNC controller and the Plasma controller you can take it out of startup routine interesting concept go figure not all machine will let you take out sub system and still work correctly