Table of Contents
Advertisement
6.1.2.
Combination with valve types and mounting versions
The positioner Type EP 501 / process controller Type EP 501 C can be mounted on different continuous
valves. For example on valves with piston, membrane or rotary actuator. The actuators can be single-acting or
double-acting.
• For single-acting actuators, only one chamber is aerated and deaerated during actuation. The generated
pressure works against a spring. The piston moves until there is an equilibrium of forces between compressive
force and spring force. To do this, one of the two air connections must be sealed with a threaded plug.
• For double-acting actuators the chambers on both sides of the piston are pressurised. In this case, one
chamber is aerated when the other one is deaerated and vice versa. In this design, no spring is installed in the
actuator.
Two basic device versions are offered for the positioner Type EP 501 / process controller Type EP 501 C; they
differ in the attachment option and in the position sensor.
Device.version.NAMUR:
An internal position sensor is used which is designed as a rotary potentiometer.
The device is mounted directly on the actuator or attached to the side.
Device.version.Remote:.
An extern position sensor (linear or rotative) via a digital interface.
The device is attached to a wall either with a DIN rail or with a mounting bracket (remote design).
6.2.
Designs
6.2.1.
Type EP 501, 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).
6.2.2.
Type EP 501 C, process controller
Type EP 501 C 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 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.
14
english
Typ EP 501
Description of System
Advertisement
Chapters
Table of Contents
