Proximity wiring for limit switches, safety relay and a contactor

**john swift** · 08-05-2019

just had a look at the 2DM860H and the power supply terminals are marked as AC input
(the 2DM860 appears to be a version of the 2DM860H with a DC supply input )

your diagram shows the power supply as a DC supply

check the relay can break the DC supply current

otherwise you may find the DC current either burns the contacts due to the arc jumping across the contacts or welds them closed

( the arc when a switch breaks an AC current will be extinguished as the mains voltage drops to zero 100 times per second )

usually switching the DC supply to a stepper driver it is not recommended your likely to damage the driver(s)
I expect the drivers with an AC supply input will have a smoothing capacitor after the bridge rectifier that's large enough to absorb the back EMF when a DC supply is disconnected

John

**CharlieRam** · 09-05-2019

Originally Posted by john swift

just had a look at the 2DM860H and the power supply terminals are marked as AC input
(the 2DM860 appears to be a version of the 2DM860H with a DC supply input )

your diagram shows the power supply as a DC supply

check the relay can break the DC supply current

otherwise you may find the DC current either burns the contacts due to the arc jumping across the contacts or welds them closed

( the arc when a switch breaks an AC current will be extinguished as the mains voltage drops to zero 100 times per second )

usually switching the DC supply to a stepper driver it is not recommended your likely to damage the driver(s)
I expect the drivers with an AC supply input will have a smoothing capacitor after the bridge rectifier that's large enough to absorb the back EMF when a DC supply is disconnected

John

Hmm....so should I use a contactor instead of a relay and if thats the case should I also put it on the 240v a.c. side instead of the 70vdc? Does the safety relay wiring look right from the charge pump output? Oh and one last thing....are the alarm outputs for the drive NC or NO? I had a look in the data sheet but couldn't work it out??
Cheers,
Charlie.

Sent from my SM-G920F using Tapatalk

**Clive S** · 10-05-2019

Originally Posted by CharlieRam

Hmm....so should I use a contactor instead of a relay and if thats the case should I also put it on the 240v a.c. side instead of the 70vdc? Does the safety relay wiring look right from the charge pump output? Oh and one last thing....are the alarm outputs for the drive NC or NO? I had a look in the data sheet but couldn't work it out??
Cheers,
Charlie.

Sent from my SM-G920F using Tapatalk

Charlie. Re the drive alarm contacts they can be either NO or NC and can be changed in the software of the drive with a rs232 cable plugged into the side socket on the drive. but IIRC I thought there was a speed limit of about 300 rpm for the stall detection. But I don't see this in the manual anymore !!

It is a little confusing the way you have drawn the circuit as you stated

Another pole connects the 70v side of the toroidal transformer to power the steppers.

which would be AC but then you mention 70vdc ie DC. As John has indicated it is not good to switch DC with a relay.

**CharlieRam** · 10-05-2019

Originally Posted by Clive S

Charlie. Re the drive alarm contacts they can be either NO or NC and can be changed in the software of the drive with a rs232 cable plugged into the side socket on the drive. but IIRC I thought there was a speed limit of about 300 rpm for the stall detection. But I don't see this in the manual anymore !!

It is a little confusing the way you have drawn the circuit as you stated which would be AC but then you mention 70vdc ie DC. As John has indicated it is not good to switch DC with a relay.

That's more down to my diagram skills sorry! The drives take a.c. or d.c. but the Toroidal psu is rectified and is 70vdc so it looks as though it will be better to use the solenoid to power a contactor on the 240v side.
These drives dont have stall detection as far as I'm aware, maybe you're thinking of the Leadshine ones?

Sent from my SM-G920F using Tapatalk