hot-air rework station - 303D - automated switching

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1

I am interested in using the hot-air rework station - 303D in an automated application. This requires turning the station on/off via an output from my controller. I originally planned to switch the 120Vac supply directly, but realized this would bypass the cool down function.

Is there a recommended method for automatically switching this unit via a control source? I.e. does the PCB have any input pin designed for this purpose?

https://www.sparkfun.com/products/14557

Thanks,

Brendan

2

Hi Brendan.

Just disconnecting power would bypass the auto cool down.

What you’re going to need to do is open the unit and replace the power switch on the front panel with a relay. That way you’re emulating a switch toggle and the cool down will still function. The unit won’t know the difference.

3

Hi Chris,

Thanks for the response. This is indeed what I tried: I routed both common connections through a spst-NO relay and then back to the switch. This did not power on the unit. I then tried only one common through the relay with the other wired as shipped, I was able to power on but the unit stayed active (with my control output off) until I removed power.

Does this behavior sound expected? A dpdt-NO relay would be more appropriate I assume. I want to keep the toggle switch in series to act as a fail-safe means to remove power.

Thanks,

Brendan

4

Hi Brendan.

With the existing toggle switch in series, you’d need to leave that switch in the on position all the time to be able to connect and disconnect power through the common terminal.

What you might try is a DPST relay to replace the existing switch, then add another switch (or use the existing power switch) that just disconnects the main power from the power input wires. Hitting the rewired switch would bypass the cool down, but if you’re using it as a fail safe, it disconnects power to everything.

Unfortunately I don’t have a schematic for this unit so I don’t know if both common terminal wires should be isolated from one another somehow. If you’re not keeping those isolated, that could be causing the issue you’re seeing.