[awpross]

I have a Problem with the ExtInOut board.

I use the 24V version abd experience the following Problems:

Optocouplers are getting very hot when Input is 24V.

When switching other Relais, connected to the internal Out, the ExtInOut switches some inputs off and others to on for a short time period.

It seems that the Inputs are not filtered and not Voltage stabilized.

Therefore the ExtInOut seems to have issues in the Input. I already rewired the entire machine to fit to the new ExtInOut board, but what can I do now??

[awpross]

After a bit of research I noticed, that all Relays are also On for a short period of time.
Maybe an Issue of the old MK3 without the red connector??

[PlanetCNC]

Current limiting resistors in front of optocouplers are getting hot, not optocouplers.
You can limit their current by adding additional resistor before input. In situation when lots of inputs are ON most of the time this i good idea. We'll add this recommendation to manual.
With 12V power this should not be an issue.

Inputs are triggering because of interference in data cable/connection. Make sure you use shortest possible cable.
Relays are noisy devices. They cause lots of ripple noise on power supply line. Reverse diode is a must but often not enough and CR is needed. I always use separate filtered power supply for all relays and it solves the problem.

[PlanetCNC]

One other thing - board voltage (24V or 12V) applies only to relays. Inputs are completely independent and can use anything from 5V up. On higher voltages current limiting resistor is a must.

[awpross]

I don't understand exactly why this problem doesn't exist with the "old" Ext v1.1 and the PoExtBusOC16.
Is there a change in resistor of the new ExtInOut so the current on the data wire may be lower and therefore more sensitive to external interferences?

I tryed using a extra power supply for the Controller, but still no luck.

Directly connecting the Powersupply of the ExtInOut with a short wire directly to the powersupply of the MK3 reduced the interferences a bit, but they are still there.

I now try to add a Diode to the relais. Maybe that helps. But there are many relais in my CNC machine.

Do you have any recommendations on reducing the interferences with a working example ?

[awpross]

Conclusion: I hate Relais and Valves without reverse diod.

That's some "fun" for me to add Diods to any relay and magnetic valve, but it works if I do that.

As recommended on some websites, i have decided to use a combination of diode and Z-diode as shown in the attached Image.
This should optimize the transition between ON and OFF by limiting the reverse Voltage to Z-Diode reverse voltage + Diode forward voltage without a "short circuit" in transition.