Wiring up the Alarm output on Leadshine AM882

[irving2008]

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]

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]

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]

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

[Lee Roberts]

Happy Days

Joel

Thanks for taking the time to share Joel, I'm sure some will find your info usefull.

Good luck and welcome to the forum !

[EddyCurrent]

There are drawings here; http://www.mycncuk.com/threads/6565-...2213#post52213
of how I wired them.

[m_c]

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

One thing to be aware of with doing this, is the alarm outputs may have a slight voltage drop (I've just checked the EM manual and it doesn't give any specs, but electronic open collector type outputs typically have a voltage drop, unlike true mechanical relay contacts). So if you connect multiple drives in series, you risk increased interference/noise issues.
I.e. if you're connecting to a TTL level type input, which needs a guaranteed voltage below 0.7V to be active, if you connect 4 drives with a 0.1V drop, you then only have a noise margin of 0.3V.

Off course, the exact effect will vary depending on the kind of input you're using. If you were to get noise problems, the simplest solution would be to add a relay controlled by the alarm/e-stop circuit, as a reasonable amount of current is needed to activate the relay, which should be far greater than anything noise/interference would cause.

[joel0407]

One thing to be aware of with doing this, is the alarm outputs may have a slight voltage drop (I've just checked the EM manual and it doesn't give any specs, but electronic open collector type outputs typically have a voltage drop, unlike true mechanical relay contacts). So if you connect multiple drives in series, you risk increased interference/noise issues.
I.e. if you're connecting to a TTL level type input, which needs a guaranteed voltage below 0.7V to be active, if you connect 4 drives with a 0.1V drop, you then only have a noise margin of 0.3V.

Off course, the exact effect will vary depending on the kind of input you're using. If you were to get noise problems, the simplest solution would be to add a relay controlled by the alarm/e-stop circuit, as a reasonable amount of current is needed to activate the relay, which should be far greater than anything noise/interference would cause.

Thanks mate. Makes sense. I don't know much about open collectors.

Happy Days