Controlling an external solenoid valve Agilent 7890 GC

[Peter Apps]

Hi Peter,

Yeah, that was your post. An oldie but a goodie

I did what you mentioned, but unfortunately, nothing happened. To be more specific, I did the following:

(1) Connected pin 1 (of the external events output) to terminal 1 of the solenoid valve, and pin 3 to the ground terminal of the valve. Nothing happened. Turned Valve 5 ON in the GC keyboard. Nothing happened.

(2) Pin 1 to terminal 1, and pin 3 to terminal 3 of the valve. Nothing happened with Valve 5 turned on or off.

Peter, you connected your solenoid valve to the internal valve drivers? (1-4). My solenoid valve draws 8 W at 24 VDC. Maybe that's the problem?

Yes, I used the connectors on the circuit board inside the right hand cover. My valve had only two wires, and I followed Gasman's pin numbers which as I recall had the two wires connecting one above the other on the connector block. I think that you need to connect your terminals 1 and 2 to the GC.

Peter

[GasMan]

If you solenoid needs 8 Watts, that is part of the problem. This means that the current needed is 330mA. The maximum current that can be supplied is 75mA. You need a solenoid that draws only 1.5 Watts.

Gasman

[Gaston]

Heh, I had no idea about the power requirement - just looked at 24 VDC and said yeah, that's the one!. The devil's in the details. Oops.

I will now try to get a smaller valve with a lower power requirement and report back Thanks for your useful comments

[arthurmcchan]

Hi,
I am wondering about the same thing too. I actually want to drive my valves using the internal valve drivers. I configured valves 1-4, and tried turning them on/off while measuring the voltage at the pins underneath the side cover of the 7890 GC. I saw the same thing (constant at 28V). Do I need to put the valve on there to test?

I want to avoid using the external valve drivers because the load for each valve is 2W and I will be driving 2 valves.

Also, anyone know what is the right Molex connector?

Thanks!