(Redirected from PSH)
PS
A Pressure Switch is specified as PS on instrument bubbles on Piping and Instrumentation Diagram. A pressure switch provides a discrete input to the PLC. The Pressure Switch is typically used as a method of control in tanks, vessels and over all process control.
Note that a pressure switch is different than a Pressure Transmitter in that a pressure switches sole function is to provide a binary TRUE or FALSE into the PLC. This approach simplifies programming.
Types
There are several different types of Pressure Switches:
- Mechanical Deflection
- Piston
- Strain Gauge
- Semiconductor Piezoresistive
- Piezoelectric
- Thin Film
- Variable Capacitance
Configuration and Alarms
Configuration (Normal State):
- Normally Open (NO)
- Normally Closed (NC)
Alarms in the PLC can be:
- Pressure
- High
- Low
- High/Low
- Differential Pressure
- High
- Low
- High/Low
Pressure Switch Companies
- ASCO Valve Inc.
- Ashcroft Inc.
- Barksdale Inc.
- Direct Controls
- Heise
- Kobold Instruments Inc.
- Power Ignition and Controls
- SOR Inc.
