Absolute Modules
Pneumatic Inputs
Pneumatic inputs consist of: 16 - Px Inputs, Control Pressure Inputs, and Calibration Inputs.
All DSA 3017/3217 Px inputs are .063 inch bulged tubulations. These tubulations are designed to
accept any .063 inch tubing manufactured by Scanivalve Corp. DSA 3018/3218 Px inputs are 1/8
inch Swagelok fittings.
Control inputs consist of: CTL1, CTL2, and PrgCTL. These inputs are used to switch the valve logic
to each of the four(4) states: Operate, Calibrate, Purge, and Isolate. The pressure required to switch
the valve logic is dependent upon the input pressure. 90 psi is required for input pressures up to 500
psi. Input pressures greater than 500 psi require 120 psi control pressures. The Digital Sensor Array
module is only available in the ISO-Purge Valve configuration. Figure 14 shows the Absolute Valve
Logic. Figure 15 shows the Iso-Purge Valve Logic.
The Calibration input is an .063 inch O.D. tubulation in a DSA 3017/3217.The DSA 3018/3218 uses
a 1/8 inch Swagelok fitting for the calibration input. It is normally connected to a source of calibration
pressures. Internally, this input is manifolded to all of the sensors through the calibration valving.
For single range, absolute DSA 3218 modules, the CAL A port is used to apply the calibration
pressure. For dual range, absolute DSA 3218 modules, the CAL A port is used to apply the
calibration pressure to the first range, and the CAL B port is used to apply calibration pressure to the
second range. Reference Figure 19 for all of the layouts of pneumatic interface panels of DSA 3218
modules.
MODE
CTL1
CTL2
CTLPRG
Operate
Calibrate
90 psi
90 psi
Purge
90 psi
90 psi
90 psi
Isolate
90 psi
Figure 13 - Absolute Modules Control Pressure Truth Table
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