Hardware Interface requirements

[ScottHorn]

We are currently using clarity to control a relatively simple custom built LC system, mostly for SEC. We are planning to build a system for immunoaffinity chromatography and would like to use clarity on a separate pc to control it. Is another copy of clarity necessary, or can we purchase a second license and hardware key for the second pc? Also, this system will contain at least 4 and possibly even 6 mutliposition valves (valco/upchurch, controlled via TTL). What interface will allow me to control the greatest number of valves?

[Ivan Vins]

The Clarity software license is bound to the HW key and could be used on a single PC only.

You may buy another Clarity station (C50) to be run on second PC or just upgrade your current station with an Add on instrument (C550) to run both your systems from a single PC. You will need a free A/D channel on your A/D board for the second system analog signal acquisition - another A/D board could be added to existing station.

With exeption of U-PAD1 and U-PAD2 all our A/D boards have 8 TTL digital outputs which could be used for valve control. With the LC control module (A24) selected valve types (including the VICI and Upchurch) could be controlled by serial RS232 line - this will be preferable for multiposition valves.

[ScottHorn]

Thanks for the reply. I was unaware that the valves in question supported an rs232 interface. I have another question regarding Clarity and the system we are putting together. We need to monitor pH during the run. I've found a suitable electrode and flow cell combination, but I'm not quite sure as to the best way to bring this data into clarity. Could I just treat the electrode as a second detector (in addition to UV), and hook the analog inputs on my A/D card directly to the leads on the electrode, or do I need a pH meter with recorder outputs between the two? Also, could the state of this second signal be used to control valves and fraction collectors in the same manner as the UV signal?

Scott Horn

[Ivan Vins]

Clarity A/D boards could serve as a sensitive Voltmeter with high input impedance (see the specifications)- I believe it could be used to measure the electrode potential directly (however it may depend on the required sensitivity). The signal will be in mV, not in pH units if the electrode will be connected directly.

The signal could be monitored as a second detector signal and used as input event in the Clarity method Event table or as a source for the FC.