PICARRO G2302 User Manual page 30

Configuring a Valve Sequence
Each "step" sets the rotary valve to a single position and activates the indicated
solenoid valve(s) for a set period of time. Multiple steps can be carried out in
sequential order to switch between different gas sources, flush out a manifold, or
other gas handling operation. Create the number of desired steps in the
sequence by clicking the up/down arrow for "steps".
For each step select the box for each solenoid valve to be opened. The check
mark in the "current valve state" window indicates a solenoid valve is open.
Note: In this example, we assume normally closed (NC) valves are used. A
check indicates current is flowing to the valve thus powering it open. The
positions from left to right correspond to solenoid valves V1...V6.
The rotary selector valve position can be set in the column labeled "Rot. Valve
Code". Enter the number that corresponds to the desired valve position. A value
of 1 in this field corresponds to position 2 on the Valco valve. Only one rotary
position can be selected per step.
Step duration is determined by the value entered in the "duration (min)" field,
where the duration of the step is in minutes. If duration values are set to <0.1
minutes they may not be carried out correctly.
The "valve code" field is a configuration- dependent, read-only display field that
shows the total state of that particular step in a numerical code. Should the most
upper right grey box display a value of 512, 256 or be greyed-out, that indicates
no rotary selector valve is connected to the instrument, or it is not functioning. For
each individual measurement the analyzer makes, the valve codes and rotary
valve positions corresponding to the valve state(s) at that point in time are saved
alongside the concentration data.
Once the valve sequence has been programmed, it can be saved using the
button "save valve sequence file"—it will be saved under the sequence file
number selected.
Loading and Running a Saved Sequence
To load a valve sequence file, select the desired "sequence file number" and
press "load valve sequence file". If the user has been running a different
sequence from the one that was loaded, the user needs to press "Next Step" to
initialize the newly selected sequence.
Picarro G2302 Analyzer User's Guide
Rev. B 1/14/11 30