CONTROL VALVES
The Digital Sensor Array does not require control pressures for normal operation. It does require control
pressures if a multipoint or quick zero calibration is to be performed. Truth tables are different for each
module type.
Standard Modules
Pneumatic Inputs
Pneumatic inputs consist of: 16 - Px Inputs, Control Pressure Inputs, and Calibration/Reference
Inputs. Each valve block has its own set of pneumatic inputs.
All Px inputs are .063 inch tubulations or Swagelok fittings depending on the module. Each valve
block contains eight(8) Px inputs. Digital Sensor Array modules are capable of measuring pressures
up to 850 psid.
Control inputs consist of: CTL1, CTL2, CTL, and RTN. These inputs are used to switch the valve
logic to each of the five(5) states: Operate, Calibrate, Quick Zero, 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
Control inputs are .063 inch tubulations in a DSA3017/3217or 1/8 inch Swagelok fittings in a
DSA3018/3218. The Digital Sensor Array module is only available in the ISO-Purge Valve
configuration. Figure 11 shows the ISO-Purge Valve Logic.
Calibration/Reference Inputs consist of a Calibration input and a Reference input. These inputs are
.063 tubulations in a DSA3017/3217 or .1/8 inch Swagelok fittings in a DSA3018/3218. The
Calibration input is normally connected to a source of calibration pressures. Internally, this input is
manifolded to all of the sensors through the calibration valving. The Reference input provides a
point of reference for the transducers. All of the sensors in each block of eight share a single
reference.
MODE
CTL1
CTL2
CTL*
CTLPRG
Operate
Calibrate
90 psi
90 psi
Quick Zero
90 psi
90 psi
90 psi
Purge
90 psi
90 psi
90 psi
Isolate
90 psi
* CTL is generated by the DSA module
NOTE: Control Pressures may be increased to 120 psi for operation at 850 psi FS
Figure 11 - Standard Modules Control Pressure Truth Table
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