High side digital (signalling) outputs?

Henry Tonoyan 5 years ago in Master modules / MC4x updated by Nick Pridham 5 years ago 3


I'm relatively new to the IQAN system. I'm currently using the MC43. Is it possible to have high side digital signalling outputs? I'm interested in controlling some industrial devices that accept 24V digital inputs. From what I understand, most of the digital outputs have some sort of fault detection on loads lower than a few hundred milliamps. The only way around it I found is to use PWM outputs, which are limited and also seem like a bit of a hack.

Would be great to know if this is possible.


Hi Henry,

What signal does the industrial device want to receive and what is the load on the device input ?


Hi Nick,

The device is a SICK safety LIDAR (TiM781S). You can find the specs here: https://cdn.sick.com/media/docs/4/54/254/Operating_instructions_TiM781S_en_IM0083254.PDF.

It uses opto-isolated digital inputs which share a common ground so they need to be high-side switched and the load is very low. According to the datasheet 0.7mA min, 5mA max in the ON condition.



Hi Henry,

The high side drivers have a 2mA leak and so you can create a non safe design by using pull down resistor on the output and switching off the under current check. (image attached) This is a hack to get something working but in general the IQAN drivers are designed for driving much larger loads.