Author Topic: MC050-10: all output pins go to FULL POWER when power supply is cut.  (Read 4825 times)

ET

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I'm programming an MC050-10, and an OX012-10 to control a paving machine.
A serious problem that occurs is that all output pins go to full power when the power supply is cut to the controller and/or output expander.
This will happen when, for example, any of the the emergency cut-off safety switches on the outside of the machine are used.
For about two seconds after the emergency stop is pulled, all pumps/motors go to full speed, since they are connected to output pins on the controllers.
For obvious reasons, this is unacceptable.

Is there something to set in the GUIDE program, so that this does not happen?

blue22

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #1 on: July 26, 2012, 11:06:31 PM »
Are the outputs low side drivers?  I have had problems with using a battery feed and a low side output on the Plus1.

I had to use a relay to stop the device from being activated when the power was off to the controller.

Hope that helps.


ET

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #2 on: July 27, 2012, 04:31:12 PM »
I am not familiar with the term "low side driver".
However, these outputs are the multi-function pins, set in GUIDE to PWM, for either setting amps, or a duty cycle. (pinconfig 3 and 6, I beleive)
If there is no way to do this is software, I'll set up, like you, a series of relays to cut signal power.

However, this needs to be addressed in the next iteration of hardware produced by SDF.
Having outputs go to anything but ZERO upon power-up, or power-off is completely unacceptable.
No other piece of machinery or hardware controller that I've used is designed this way.
It's unsafe, it's uncontrolled, and most importantly, it forces you to add extra hardware electronics when it should be covered by the microcontrollers being built properly.

Offline hproffitt

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #3 on: July 31, 2012, 09:08:05 PM »
I could see the OX pins going to full if the default outputs were not set correctly and power was killed only to the controller.  I have never had a problem with a controller momentarily outputting a full signal when power is cut.  On the other hand, we do not like to cut the power to the controller from a safety switch - we always try to make it an enable/e-stop input that must be 'high' for the outputs to work; this way the controller is always monitoring the system.

I would be interested in looking at the program, if you would like to attach it here or email it to me.

ET

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #4 on: August 01, 2012, 06:20:47 PM »
MC050s do not have, but output expanders do have, the "DefOutputValue" signal on their output pins' config page.
Is this the default you are referring to?

Offline hproffitt

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #5 on: August 03, 2012, 02:20:27 PM »
Yes, just the expander parameter is what I was referring to.  It doesn't really explain all of what you are describing, but I thought it could be a part of it.

ET

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Re: MC050-10: all output pins go to FULL POWER when power supply is cut.
« Reply #6 on: August 03, 2012, 04:45:38 PM »
This is happening on both the MC050's pins and the expander.