Chromatography Forum

I am trying to find a 5V TTOL contact closure to operate a 6 port Valco valve on my 5890 operating Chemstation. Is it controlled in Chemstation by the "Valves/Relays" page under Instrument Control? Where can I plug the valve in to get the contact closure?

It's a long long time since I have seen a 5890, I do not recall there being a contact closure to operate a valve on the 5890. The valves on the 5890 were air actuated and I remember that there was a special board that had to be installed to enable valves to be controlled. I believe that the very early 5890's only alowed control of two valves, but later models did allow four valves to be controlled. The purge valve function for a capillary inlet was used to control the valves. If you look on the left side of the GC close to the inlets, you should see two sockets close to each inlet position. One is for the heater/sensor and the other is for the purge valve. The control for the valve is either 24 Volt or 12 Volt. You could use this to control a relay which would then give you contact closure for your valve.

Gasman

Thanks gasman. I was lookng at the purge valve and it's 24VDC as you said.

If I get a chance today, I'll look at one of our 5890 units, I used it the last two days, and will be using it today as well.

Thanks KM - I'll fook fed to it.

I don't see any electrical contacts on our 5890 units, or software for that, sorry.

Thanks - I'm going with Gasman's advice above. I'll step down the 24VDC from the purge valve to 5VDC and that should work.

Be careful here. I have seen some HP/Agilent 5890 or 6890 where the 24 Volts is supplied to the solenoid valve and the ground side was switched. This meant that there is always 24Volts on the solenoid valve. If the 24 Volt supply is switched, you should be OK.

Gasman