15
Description of System
5.2. Designs
5.2.1. Type 8792, positioner
The position of the actuator is regulated according to the position set-point value. The position set-point value is
specified by an external standard signal (or via field bus).
5.2.2. Type 8793, process controller
Type 8793 also features a PID controller which, apart from actual position control, can also be used to implement
process control (e.g. level, pressure, flow rate, temperature) in the sense of a cascade control.
The process controller Type 8793 is operated with a 128 x 64 dot matrix graphics display and a keypad with 4
keys.
The process controller is linked to a control circuit. The position set-point value of the valve is calculated from the
process set-point value and the actual process value via the control parameters (PID controller). The process set-
point value can be set by an external signal.
5.2.3. Typ 8793, Remote-Design
Depending on the connection type of the position sensor, Type 8793 functions as a
• Process controller or
• Positioner
The following connection options are possible:
Function
Type 8793
Interface Position sensor Setting in the menu (ADD.FUNCTION)
Process controller digital (serial) Remote Sensor Type 8798 POS.SENSOR → DIGITAL
For menu description see Chapter
“26.2.19”
Positioner analog
(4 ... 20 mA) *
Any, high-resolution position
sensor
POS.SENSOR → ANALOG
For menu description see Chapter
“26.2.19”
Table 2: Connection options type 8793 with external position position sensor
* If the position sensor is connected to the process controller Type 8793 via the analog interface, it can be
operated only as a positioner.
The options for connection of a position sensor are described in Chapter “12.4. Remote operation with
external position sensor”.
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