Scanivalve DSA 3000 Series, Инструкция по эксплуатации и обслуживанию

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Figure 15 - Isolate-Purge schematic
Isolate-Purge Valves
All Digital Sensor Array modules have Isolate-Purge valves. This valve adds another set of valving
which permits the input lines to be purged at pressures up to 850psi. This is especially useful when
Digital Sensor Array modules are used in applications where corrosive gases may be present in the
input lines. This permits the safe use of a high pressure purge of low pressure sensors. A schematic
of the Isolate-Purge Valves may be found in Figure 15.
The user must be familiar with the Control Pressure Truth Table for the valve being used. This table
shows the pressure requirements for each mode of the Digital Sensor Array valves. The basic
modes are quite simple to set. The purge mode
MUST be established in a set order in order to
protect the sensors and Calibration modules from damage.
Isolate-Purge Mode Procedure
1. Set the internal valve to the Calibrate mode .
2. Set the Calibrator(s) to the Zero Mode. If Scanivalve Corp Calibrator modules are
being used, Steps 1 and 2 can be implemented by setting the Calibrator module(s)
to the Cal Zero mode using the CALZ command.
3. Set the calibration valve(s) to the Purge mode by applying CTLPRG pressure.
4. Apply the Purge pressure.
It is also imperative that a procedure be followed when switching from the Purge mode to
one of the other modes.
1. Shut off the Purge pressure. Allow sufficient time for the input lines to stabilize. The
actual time required will depend upon the physical characteristics of the input
tubing.
2. Switch the valve(s) from the Purge mode by removing the CTLPRG pressure.
3. Switch the valve(s) to the desired mode.
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