Relay for Hypertherm 45

Hi, currently I am using the Solid State Relay (RS Components Part # 888-6843) to wire the 7i76e board and Hypertherm 45. The A2 is connected to pin 3 on the Hypertherm 45 cpc, A1 is connected to pin 4 on the cpc(torch on connection) and 14 on the relay is connected to output on 7i76e, 13 on the relay to 0v. But when I turned on the power on the Hypertherm 45, the temperature led and fault led on the Hypertherm 45 came up. From what I know, it's "stuck start" issue because there is power on pin 3 so Hypertherm 45 won't start properly. Is the issue caused because I use the RS 888-6843 solid state relay? Is there any way to solve the problem? Should I switch from the RS 888-6843 solid state relay to the dry contact relay? Thanks.

There is bit of a disconnect here. Looking at the RS Components listing page, The circuit diagram on the part is different to the one in the data sheet. (pinouts reversed) I'd have to check how I've wired this in on my table but I'd start by experimenting by powering up the trigger side and ensure the led light comes on before connecting it to the plasma cutter.

This relay certainly works on my Thermal Dynamics machine.

I use the same relay and that is how I have it wired up,




Maybe the output to the relay is inverted?

the Hypertherm got a internal double schmitt trigger
so you can use a simple FINDER relay isolateds circuit socket any voltige you like
you will not see any EMI from that
friends got 2 H45 in work and no problem at all with this Plasma

The relay I have here is different to the one in the Data Sheet (as seen in the attached picture). Should I swap the A1, A2 connection to 7i76e and 13, 14 to the Hypertherm?
One more issue I have now is I could not get the signal from the output pin (hm2_7i76e.0.7i76.0.0.output-00) on 7i76e to the relay as testing the Torch Pulse in Plasmac. I can see the value in the output pin changing from False to True in Halmeter but could not measure any voltage in the output pin? How do I check if the output pin is working properly? Does 7i76e send a voltage signal to the relay to close the circuit and activate the relay?

You should be able to see the led on the relay light up when the relay is activated. Yes the 7i76e should be sending a signal to the relay to activate it.

Check for continuity between 13 and 14. Their should not be continuity between them without the relay being turned on.

I would put a multimeter on TB6 - 17 ( for output-00) and 0v and see if you get 24v (or what voltage your system is running) when the torch is pulsed.

If you are getting the voltage reading double check the wiring to the relay and see if you get a light on the relay when pulsed.

for the standard torch on
on Hypertherm
the A2 A1 goes to the 7i76 where on sinking the A1 goes to Vfield and a2 to a port out
and the 11 from the relay to 3 Hyper
and 14 relay to 4 hyper CPC17 connector

as there are 18VDC on this pins to be mesured it you short them the arc firers

I just bench tested one of my spare relays, A1 should the the + voltage from the 7i76e and A2 should be 0v. Then 14 and 13 should go to the Hypertherm CPC port.

I dont know what is going on at RS components but the diagram on the actual relay it self is different to the diagram they provide on their web site.

the relay matches perfect the Hypertherm recomendation
its a optical relay with open drain
we all use most standard relays cheep < 5USD for the torch on at hypertherm

so you are fine with your settings