Wiring up the Alarm output on Leadshine AM882

**m_c** · 23-02-2014

The Fault ouput is Open Collector, so provided there's not an issue with wires being connected wrongly, then you can connect it directly.
If noise is an issue, or the possibility of wires being connected wrongly, then having an opto would likely be beneficial.

**irving2008** · 23-02-2014

The Fault output on the EM806 (i guess that's what you mean by the Alarm output) is a floating optoisolated transistor. You could do it two ways:

1. Flt+ to PIC Vcc, Flt- to the input pin and a 1k resistor from input to PIC ground. Input will go low on fault; or

2. Flt+ to PIC input, Flt- to PIC ground, 4k7 resistor from PIC Input to PIC VCC. Input goes high on fault.

**m_c** · 23-02-2014

Wouldn't using an internal pull up be just as easy?

**dsc** · 23-02-2014

Looking at the diagram in the manual again, I thought that if I use R = 4.7k, the PIC pin will see 5V when the FLT output is disabled, and 0V when the FLT output is enabled. With nothing passing through the FLT optotransistor in the EM806 ie. with no fault, the PIC pin should see 5VDC on the input, if the FLT optotransistor is enabled, it would pass current down to 0VDC, thus bringing the PIC pin down to 0VDC. Or am I missing something?

Regards,
T.

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**m_c** · 23-02-2014

That'll work fine.

**irving2008** · 24-02-2014

Originally Posted by dsc

Looking at the diagram in the manual again, I thought that if I use R = 4.7k, the PIC pin will see 5V when the FLT output is disabled, and 0V when the FLT output is enabled. With nothing passing through the FLT optotransistor in the EM806 ie. with no fault, the PIC pin should see 5VDC on the input, if the FLT optotransistor is enabled, it would pass current down to 0VDC, thus bringing the PIC pin down to 0VDC. Or am I missing something?

Regards,
T.

That was my option 2 and will work fine, but if you read page 3 of the manual you'll see it says that the output is low impedance in normal operation and goes high when there's a fault, i.e. the logic is reversed. The reason for this is if you put the pullup at the controller end and the cable gets broken or disconnected you get a fault condition.

@m_c you could use internal weak pull_up but needs to be turned on in s/w and is only 10k so more susceptible to noise in this environment. Indeed on reflection I'd probably use a 1k external pull_up for just that reason.

**joel0407** · 31-07-2017

Hey guys,

I know this thread is a little old but it's about he only decent thing that comes up when I searched "AM882 alarm wiring". I just registered to post this update.

This is just an FYI how mine worked. I have 2 motors on one axis and I didn't want the driver to sense something that would put it in to alarm and stop one motor while the other kept going. Hope that makes sense. I wanted that if one driver went into alarm that the others would stop.

Turned out really simple. In the software set the alarm to go "LOW". Run the E-Stop though as many switches as you need then end at the "ALM +" of the first drive then "ALM -" to the "ALM +" of the next and so on. After the last drive "ALM -" goes back to the control board "GND" and that's it. Job done. If any drive goes into alarm, the circuit is broken and E-Stop is activated.

Happy Days

**Clive S** · 31-07-2017

Hi Joe and welcome to the forum. There are a lot of people on here that use the AM882 drives and the later model EM806 both are very good drives and for a gantry machine a must, because like you have pointed out the alarm feature

**joel0407** · 31-07-2017

I just thought the beginning of the thread got a bit complicated with using relays and the such. I don't know if the op had used a different control board or something and it had me a little confused. I know how to use a transistor and a relay but couldn't work out the alarm port on the AM882.

I expected it to be simple open circuit and closed circuit when alarming or not. What threw me off the most was putting a multi-meter across the terminals didn't show continuity or only a few millivolts on DC. I figured there wasn't enough voltage to do any damage so I just give it a go running a jumper from the E-Stop on my Parallel Breakout board, "ALM +" then "ALM -" back to the GND on my break out board. What do you know it worked then I found it also worked jumping them all together so all good..

Happy Days

Joel