Clarity discussion forum

Hello --

I need some help controlling two Rheodyne MXII valves (one two position and one six position.) I am currently using Clarity version 7.4. Specifically, I need some help parsing out the event table to respond to external signals. I am using a UPAD2 and cable. I previously set this up a long time ago with Clarity version 3.x, and would like to set it up with 7.4:

I have one switch from a relayed contact closure going into Input 1 of the Clarity cable, and one manual rocker switch closure into Input 2 of the Clarity Cable. I need some example of how to setup the Event Table for these events.

Thanks in advance for the assistance.

CP

Hello,
it depends on what you are trying to achieve and how. Please note Clarity has a control module for Rheodyne MXII valves which allows for control of the device over USB, however as you mention U-PAD2, you are probably trying to work with the valve just using the TTL's. The control module may be easier solution to control the valve(s) in case your Clarity allows for controlling any GCs or LCs.

Regarding the usage of the Event table, we will need more information on what you are trying to achieve. When you want to turn the valves? Based on what - detector signal, time moment during analysis, external trigger from other device, ...? What the two valves should generally serve for?

Thanks, Daniel. Let me explain.

I have one two-position valve that I want to use for sample loading and injection in a semi-prep system, and a second six-position valve that I want to use for fraction collection in this same system. Both are MXII series controlled through USB.

I previously controlled the injection valve by having it switch from pos 1 to 2 at the same time as acquisition began (i.e. at the time of injection.) This was done through the control module of the valves. The collection valve I was controlling through the UPAD cable with a switch. See attachment: IN 1 is attached to an external control device, which I would like to trigger the injection valve to move from position 1 to 2 at the start of the acquisition. IN 2 is attached to a contact closure rocker switch which I would like to use for control of the collection valve.

I think this is a fairly straightforward setup. Thanks so much for your help!

Hi Chris,
the above setup depends on which control modules the station has. Supposing you are using LC Control, then everything should be covered by control modules, no U-PAD-based TTL signals should be necessary.
Clarity currently contains two control modules for Rheodyne valves. First one (the one you already use) may be able to turn the valve at the moment of injection (analysis start). This part stays. The second valve (multiposition to be used as FC) may be controlled by two different control modules - both the same as you already use or from Rheodyne valve used as FC control module.
- the first module will allow to use the valve switching based on retention time and fixed position, which might be enough for you. Lets say you use a sequence of 5 samples and you always want to move the sample to position 1 outside of run, position 2 once the run starts till 90s, position 3 during the run between 90s into run time and 120s into run time, after that position 4 until end of the analysis. If this is preparative measurement, running next sample should hold the same pattern (thus collecting whole 0-90s fraction always into position 2 from the whole sequence). This mode is not suitable for non-time based fraction collection and in situations where the following sequence runs should not use the same vials.
- the second module is dedicated module for Rheodyne functioning as FC. It allows complex synchronization possibilities, complex behavior regarding vial numbers etc (thus collecting first sample to vial 1&2, second sample to vials 3&4, third sample to 5&6, ..., collect only in case a peak appears at some specific time etc.). The downside of the second module is that the module is still in Under Development state, however can be modified quick and we would really appreciate finishing it.

An alternative to waiting before Acquisition begins for 2-position valve would be a control module for the valve serving as sampler, but such script is currently not available (could be done) and the station would also need AS Control license.

Best Regards,
Daniel