E stop opto coupler

[evermech]

Hi all. Which opto couplers are responsible for the estop circuit. Pretty sure I cooked one switching between using mpg and not. Using a G3

@masso-support

Might be an idea to show a map of the opto couplers so that we know which one does what

Guy

 

[breezy]

@evermech

Guy,

MASSO G3 Replacing Damaged Optocouplers

docs.masso.com.au

Unfortunately we don't show which is Estop.

Will chase that up.

Regards,

Arie.

 

[evermech]

@breezy

Any luck with this yet?

interesting when I have the cover off of Masso and toggle the estop button I can see a bright light on the circuit board in the area where the pendant plugs in.

Guy

 

[zombieengineer]

@evermech

April 5th was a public holiday in Australia, the Masso staff should be in a couple of hours and then Arie can get the necessary information.

 

[cncnutz]

Hi evermech

There is only 1 optocoupler used for the Estop and the chance of damaging it by plugging in the mpg are slightly less than winning the lottery 3 weeks in a row.

What testing have you done to determine the estop optocouple is faulty?

Are you aware that when you use the pendant you need to use estop 1 and not the estop2 connection?

Did you follow the estop test procedure in the link Arie sent you?

Cheers Peter

 

[zombieengineer]

Alright - reversed engineered the connections between MPG pendant wiring and opto-couplers.

TLR - Optocoupler 38 is for E-Stop

Pin	Opto	Desciption
1	+VE	+ve output, same as power given to controller
2	Not Used	Not Used
3	28	MPG A
4	29	MPG B
5	35	Resolution 1
6	37	Resolution 2
7	36	Resolution 3
8	30	X-Axis Select
9	31	Y-Axis Select
10	32	Z-Axis Select
11	33	A-Axis Select
12	34	B-Axis Select
13	38	E-Stop 1 - Main
14	ESTOP-1	E-Stop 2
15	Not Used	Not Used

!! TAKE NOTE !!

The opto-coupler input has a 6.8 k? resistor in series, probably 1/8 W. The resistors are located between the terminal sockets and the opto-couplers (they are about the size of a large grain of sand). Sustained input voltage of greater than 30V has the potential to burn these resistors out (sqrt(6800/8) = 29.1 V). On my Masso controller the opto-couplers are Toshiba TL817 which have a maximum forward current of 50 mA which translates to 340V before they fry (6800 ? x 0.05 A = 340V) - the SMD resistor is going to burn out first unless it was a very big static zap (happens too quickly for the resistor to overheat).

Test Method

With the controller unplugged (no power or other wires connected) measure the resistance between the MPG socket and the "North East" corner of the opto-coupler (top row - optocouplers 28 to 35) or "South East" corner (right side - optocouplers 36 to 38). The resistance should measure 6.8 k? for a valid connection.

I sincerely hope you find your problem and have it solved quickly.

 

[evermech]

@cncnutz

yup I know about the estop wiring and had it working for several days

didnt use Arie's test method because I didn't know which coupler to test

I switched some of the input couplers with the group of couplers adjacent to the mpg plug, no help there

I noticed that when switching the estop on and off a small light, or spark, in the area that is right in front of the mpg plug on the circuit board. Most likely in the area @zombieengineer describes as having the resistors in.

I will ohm the appropriate couplers now this morning and see if there is an issue there, if there is a problem with the circuit board is it something that might be user repairable?

Thanks for all the help Guy

 

[zombieengineer]

@evermech

Had a closer look at the rear of the MPG socket (using a USB digital microscope) and there is a little row of surface mount components - probably the resistors.

 

[evermech]

@zombieengineer

Yah I noticed those components and thought they were most likely the resistors. I mentioned in an earlier post that I can see a flash of light when I cycle the estop. I'm pretty sure the the cause of my problem is that I took an additional wire from my estop button to a motor contactor to turn off the stepper power supply when estop activated. There is also a wire going to the estop circuit off of same post. I think the spike in voltage when dropping the motor contactor back fed through the estop circuit on the Masso duh!!! Will use a separate contact on the same estop next time to isolate the 2 separate tasks. Big question is can it be repaired?

ohmed the opto couplers as described and got numbers around 16 or so

Guy

 

[zombieengineer]

@evermech

My gut feeling is "beyond economic repair" based on your comments - it may have vaporized the copper PCB tracks which will make it extremely difficult/impossible to repair, or it may have shredded the body of the resistor but left the copper track undamaged (far easier fix - heat and drag off the last remnants and solder a replacement).

My recommendation would be to take a photo of the area (if possible) and send an e-mail to Masso Support and ask what your options are.

If you know someone who can do SMD rework then they might be able to repair it but the cost could be several hundred dollars at specialist technician rates (I have no feel for the cost).

 

[mr-ben]

Try this:

Use e-stop 2. If Masso now works, simply remover the cover on the pendant connector and connect two wires to the pendant e-stop switch. Wire these is series with your

other e-stop switches. I did this on one of mine.

Ben

 

[evermech]

@mr-ben

I would like to try that could you explain it in a bit more detail please?

Right now I have the estop wired to power down the Masso and the stepper power supply so if there is trouble and I hit the estop it just goes dead. Then on power up it needs the estop cleared before you can do anything so I go to the setting page and toggle the estop from low to high and that clears it. Then I go out of settings and home the machine as normal and it's ready to run. That's my work around until I get this sorted.

@zombieengineer

i can't really see any damage at all in the area where the resistors are but as I said I can see a tiny little flash of light when toggling the estop PB. I will send all I can to Masso though and see what can be done, thanks for the advice.

Guy

 

[mr-ben]

Sure

All I did was use the pendant e-stop switch as if it were one of the main e-stop switches. To do this you must open the pendant connector that plugs into Masso.

Identify the two wires that connect to the NC contact of the pendant e-stop switch (button). Disconnect these wires from the pendant plug that plugs into Masso.

Solder a couple of wires 0nto these wires to us a extensions so you use connect them in series with the main e-stop circuit. I drilled a hole in the pendant plastic

cover to allow the wires to exit when you put the cover back on the pendant plug. ALSO you might want to consider using the relay board that Masso makes. It has 6 relays

that can be actuated by masso outputs. Handy. Maybe you do this already. Why remove power from the stepper PS when the e-stop will stop the motors in their tracks!

If I left anything out let me know. Happy to help if I can.

Ben

 

[cncnutz]

Hi Guys,

Just to correct a couple of misconceptions.

1. Estop does not bring the Axis to an immediate stop, it puts the machine into feedhold and turns off the Spindle.
   
2. If you want to bring the axis to an immediate stop then the Emergency stop output is provided. This is labeled ES and sits next to output 18
   
3. A TTL Relay can be connected to the ES output and can be used disable the motor drives.
   
4. You should not disconnect power from your stepper drives as this can damage them if you are disconnecting them on the DC side.
   For example disconnecting and reconnection DC power to Gecko drives will blow built infusible links.
   
5. To stop the drives use the Enable / disable input on your drives using a TTL relay connected to the ES output. Wire as per your drive manufacturers spec.
   

I cannot comment on the bright light you see maybe it is arcing but the voltage should not be high enough for that. [ Do not go towards the light ;-) ]
I strongly recommend that you test the Estop as per the document that Arie provided https://docs.masso.com.au/replacing-damaged-optocouplers-G3
You do not need to know what Optocouple is used. You only need to test and report the results. That will help tell the extent of damage.
With luck it is just the loss of the Pendant Estop and it may be repairable and if not you can still work without it.

Watch this video to see the relationship between Estop 1 and Estop 2. It is very simple.

Report back your test results and we can see where to go to from there.

Hope this helps
Cheers Peter

 

[jho]

@cncnutz

Hi Peter,

Is the ES output only controlled by the Estop input or is this output used in other events (driver alarm etc.)?

I ask because i want to use a relay with forced contacts and a reset button in my safety circuit, and use one of the contacts to operate the Estop input (and the other contacts to disable the stepper drivers and the spindle)

If Masso can operate the ES output in other events, i need to intergrate the ES output in my safety circuit.



kind Regards,

Jarno

 

[cncnutz]

Hi Jarno,

The ES output is used by all events that trigger an Estop.

Cheers Peter

 

[msl]

@jho I'm in the same situation as you in wanting to interface with a safety circuit. What forced contacts are you using? I can't find a 5VDC option that will work off the Masso estop output.

I also can't tell if the Masso estop is software controlled or if it hard wired with the inputs. Some more documentation on how the estop is set up would be great.

The only alterative I see is to rewire the pendent and touch screen estops into an independent 24V estop circuit an output of which would go to the Masso along with other circuits. The Masso estop output wouldn't be used.