Badger Meter SRD/SRI Valve Positioners - Manual (Page 16)

The positioner can be attached to both linear and rotary actuators
Actuators with spring force are controlled by a single acting positioner Actuators without spring force are controlled by a
double acting positioner
HART or FoxCom version:
The positioner can be operated locally by means of local keys or a handheld terminal, or remotely via PC-based configuration
or a corresponding control system
PROFIBUS-PA or FOUNDATION Fieldbus version:
The positioner can be operated locally by means of local keys, remotely via a corresponding control system, or can be
operated via PC-based configuration and operating tools
Block Diagram
s Air supply 1.4 ... 6 bar (20 ... 90 psig)
x Position
of actuator
y
1
Output
pressure
y
2
to actuator
Input (w) each
acc. to version:
•
Analog operation
4...20 mA
(+FSK)
• Digital operation
FSK
13...36 V DC
• Bus input
Operation
With the intelligent positioner with input signal 4-20 mA or superimposed HART signal, the supply takes place via the power
signal adjacent to the input
By means of voltage converter 7, derivation of the internal supply of the electronics takes place The power value is measured,
in A/D transformer 9 converted, and directed via switch 10 to digital controller 11
With PROFIBUS-PA or FOUNDATION Fieldbus, the SRD is powered by means of the bus cable The positioner is operated
from a control system by sending a setpoint (setpoint value) to the positioner The digital signal is directed via the interface
component 8 to the digital controller 11 By means of the voltage converter 7 the internal supply of the electronics is
established, fed via the bus cable
With FoxCom digital operation, a DC voltage is provided at input w On this voltage an FSK signal is modulated The
modulation contains information, such as setpoint value, sent digitally to the control unit 11 across the FSK unit 8
The output of controller 11 drives the electro-pneumatic converter (IP-module) 12, controlling a pre-amplifier 13, the
single acting (or double acting) pneumatic power amplifier 14 The output of the amplifier 14 is the output pressure y to
the actuator
The pneumatic amplifiers are supplied with supply air 1 4…6 bar (20…90 psig)
The position x of the actuator is sent to the control unit 11 by the position sensor (conductive plastic potentiometer) 15
Optional gauges 16 , pressure sensors 19 , 20 , inputs / outputs 21 (two binary outputs; a 4…20 mA output and alarm;
control inputs for ‘Open/Close’ and ‘Hold last value’) enable additional diagnostic indications and possible intervention The
mechanical limit switch 22 (optional) enables independent alarm signals
Method of Operation
Page 16 August 2014 POS-UM-00010-EN-03