AXBB charge pump fault

[northbynate]

Thanks! The e-stop design has given me quite a headache. My main design goals are:

1. Ideally I want any e-stop signal to be able to drop the contactor, even one from a pendant. That means the e-stop circuit has to monitor the reset status of UCCNC. This also means I'm covered in two ways in light of an accident. First the AXBB-E will stop sending pulses, then power will be cut to the motor's PSU. The safety relay connected to the contactor achieves this - although I'm not clear why I need an extra relay in the system if I have a 24v coil on the contactor? Is it just a way of adding the switches in parallel instead of in series? I've seen circuits (such as https://youtu.be/6dKwOsrnkb4) that build a no volt release just using a contactor.

2. I also want any e-stop to put UCCNC into reset mode which means the AXBB-E needs to monitor the status of the e-stop circuit.

3. The contactor should stay off following power outage and require a manual button press to re-energize the coil.

My conclusion was the only way to accomplish this without getting stuck in a feedback loop between 1 and 2 was to connect all e-stops to the AXBB-E then have it control a relay with the charge pump output pin as shown in the example circuit at the end of the manual. Does that seem like the right approach to you all? I really appreciate your help!

[JAZZCNC]

1. Ideally I want any e-stop signal to be able to drop the contactor, even one from a pendant. That means the e-stop circuit has to monitor the reset status of UCCNC.

You can only incorporate the pendant in the E-stop circuit if it's a wired pendant, a wireless one is software-driven and will only put UCCNC into Reset mode and not do a hardware E-stop which is the correct way.
Also, the E-stop circuit doesn't and shouldn't be driven by software so you don't monitor UCCNC you inform it an E-stop occurred using inputs.

This also means I'm covered in two ways in light of an accident. First the AXBB-E will stop sending pulses, then power will be cut to the motor's PSU. The safety relay connected to the contactor achieves this - although I'm not clear why I need an extra relay in the system if I have a 24v coil on the contactor? Is it just a way of adding the switches in parallel instead of in series? I've seen circuits (such as https://youtu.be/6dKwOsrnkb4) that build a no volt release just using a contactor.

You don't actually need a safety relay and can indeed just use the contactor wired in a latching circuit, however, using a separate Relay gives more control. It doesn't need to be a safety relay either just an ordinary ICECUBE type relay works just fine.

This relay is known as the MASTER relay in the circuit because it controls all the safety and won't be allowed to energize unless all the safety on your machine is correct.
Only when all is correct on the machine will the MASTER relay be allowed to latch, When it does it will do several things.!
#1 sends a signal to UCCNC saying it's ok to allow a Reset.
#2 power the contactor for the drives.
#3 power any other contractors in your system or allow voltage to reach contractors or relays ie: For dust extraction
#4 Turn on any LED's ie: light tower etc

2. I also want any e-stop to put UCCNC into reset mode which means the AXBB-E needs to monitor the status of the e-stop circuit.

3. The contactor should stay off following power outage and require a manual button press to re-energize the coil.

#2 As mentioned above, you inform the AXBB-E using inputs rather than it doing the monitoring. If it sees the input HIGH or LOW depending on how you configure the input then it won't allow the software to RESET.

#3 This is known as a latching Circuit and is easily done using a relay.

My conclusion was the only way to accomplish this without getting stuck in a feedback loop between 1 and 2 was to connect all e-stops to the AXBB-E then have it control a relay with the charge pump output pin as shown in the example circuit at the end of the manual. Does that seem like the right approach to you all? I really appreciate your help!

The Charge pump Output is not designed for this purpose, it's designed to monitor the connection between PC and controller so if the software crashes or PC dies the AXBB-E sees this and disables the Output. This, in turn, would drop the relay which should be incorporated into the E-stop circuit and before the MASTER relay.

[Ger21]

I use a safety relay because I got them for $10 for NOS on Ebay. If I had to pay the $200 they actually cost, I'd use Jazz's method.

[northbynate]

Thanks!! This is fairly similar to my original plan (minus the relay). I just got hung up on the wireless mpg part and the two types of estop (hard and soft). From what I understand the charge pump can be set to stop when UCCNC is on 'Reset' mode. In Jazz's case this would then be passed on to the safety relay which would in turn cut the contactor. In that case an estop from a wireless mpg could act like a hard wired estop - albiet passing through a layer of software first. Getting the contactor back on would then require both clearing 'Reset' mode in UCCNC and using the physical button to latch the coil of the contactor. I guess my question would be is it possible to have that same behavior from a wireless estop as it is from a hard wired one?

[JAZZCNC]

From what I understand the charge pump can be set to stop when UCCNC is on 'Reset' mode. In Jazz's case this would then be passed on to the safety relay which would in turn cut the contactor. In that case an estop from a wireless mpg could act like a hard wired estop - albiet passing through a layer of software first. Getting the contactor back on would then require both clearing 'Reset' mode in UCCNC and using the physical button to latch the coil of the contactor. I guess my question would be is it possible to have that same behavior from a wireless estop as it is from a hard wired one?

Don't think it works as you think, there is no setting in the software other than to keep the charge pump loaded at all times.

This is from the manual

"If the 'charge pump always on" checkbox is not set then the PWM signal is only active if the software is not in reset and inactive if in reset.

The charge pump signal can be used to enable an external electronics only if the UCCNC software is loaded or if it is not in reset making the operation of the electronics safe."

[JAZZCNC]

Sorry old friend, didn't see the email.
Had a bad back earlier this year that put me out of commission for about 6 weeks. And projects at the new house have kept me incredibly busy.
The screenset is at the top of my todo list, as soon as I can find the time. Trust me, I want it done as much as everyone else.

Sorry to hear that Gerry, I know all about Bad backs I've had one on and off for over 30yrs, one wrong sneeze can make putting my underpants on a massive chore...

Let me know when you get it done or if need any help testing etc.

[northbynate]

"If the 'charge pump always on" checkbox is not set then the PWM signal is only active if the software is not in reset and inactive if in reset."

That's what I was getting at. In this case if UCCNC goes into reset then the charge pump signal stops right? So that can be used as a way to tell if an e-stop on a wireless mpg has been hit. Thanks again for your help!

[JAZZCNC]

"If the 'charge pump always on" checkbox is not set then the PWM signal is only active if the software is not in reset and inactive if in reset."

That's what I was getting at. In this case if UCCNC goes into reset then the charge pump signal stops right? So that can be used as a way to tell if an e-stop on a wireless mpg has been hit. Thanks again for your help!

Kind of but that then defeats the point of a Charge pump, you want the charge pump working all the time.

Also, not sure it will work, you could end up stuck in a loop, Master relay won't reset because don't see the charge pump signal and you can't activate the Charge pump without resetting the software which won't come out of reset without the master saying it's safe to do so.??? Give it a try.!

[dazp1976]

Sorry to hear that Gerry, I know all about Bad backs I've had one on and off for over 30yrs, one wrong sneeze can make putting my underpants on a massive chore...

Let me know when you get it done or if need any help testing etc.

I've just had 2 spinal nerve block injections, so you're not alone guys

I also need to figure out my estop circuit and wire up all my inputs next. I'll be looking through all the advice that's been given.
No £5 bob's this time, hope to do this one properly.
(Even though my box has turned out to be a little small ) Balls!.