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Description of System
5. DESCRIPTION AND FEATURES OF THE
TYPE 8792/8793
5.1. General description
The positioner Type 8792 / process controller Type 8793 is a digital, electro-pneumatic positioner for pneumati-
cally actuated continuous valves. The device incorporates the main function groups
- Position sensor
- Electro-pneumatic control system
- Microprocessor electronics
The position sensor measures the current positions of the continuous valve.
The microprocessor electronics continuously compare the current position (actual value) with a set-point position
value specified via the standard signal input and supplies the result to the positioner/process controller.
If there is a control difference, the electro-pneumatic control system corrects the actual position accordingly.
5.1.1. Features
• Models
- Positioner (positioner) Type 8792
- Process controller with integrated positioner, Type 8793.
• Position sensors
- intern high resolution conductive plastic potentiometer or
- extern non-contact, non-wearing position sensor (remote).
• Microprocessor-controlled electronics
for signal processing, control and valve control.
• Operating module
Operation of the device is controlled by four keys. The 128 x 64 dot matrix graphics display enables you to
display the set-point or actual value and to configure and parameterize via menu functions.
• Control system
The control system consists of 2 solenoid valves and 4 diaphragm reinforcers. In single-acting actuators the
working connection 2 must be sealed with a threaded plug.
• Feedback (optional)
The feedback is implemented either via 2 proximity switches (initiators), via binary outputs or via an output
(4 – 20 mA / 0 – 10 V).
When the valve reaches an upper or lower position, this position can be relayed e.g. to a PLC via binary outputs.
The operator can change the initiators or limit positions via control lugs.
• Pneumatic interfaces
Internal thread G1/4“
• Electrical interfaces
Circular plug-in connector or cable gland
• Housing
Plastic-coated aluminium housing with hinged cover and captive screws.
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