SCHIEBEL SRG5 Series Manual

Positioner SRG 5xx
DS-ENGLISH-SRG5XX-V2.00-2012.07.17
SEC-DS-ENGLISH-SRG5XX-V2.00-2012.07.17
Positioner SRG5ss

1 General

The SRG5xx positioner (see Figure 1) facilitates the control of an electric actuator by
means of a set point with voltage output 0(2)...10V. A potentiometer with a resistance
value of 100 to 10k is used as an actual value in the actuator. The position control of
the actuator is carried out using the SRG5xx, i.e. the positioner ensures that the actual
value and thus the position of the actuator follows the set point.
Figure 1: Symbol

2 Operation and electrical connection

The set point voltage U 0(2)...10V is connected to the terminals 77 (plus) and 78 (minus). The actual value
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(actuator position) is determined in the SRG5xx from the position of the actual value potentiometer (connected
to the terminals 74 to 76) coupled with the actuator. This actual value is compared with the set point in the
positioner. If both values are equal except for a residual difference (adjustable with potentiometer D), none of
the two relays (K3, K4) on the positioner picks up (see Figure 2).
Figure 2: Basic wiring diagram
If the set point is larger than the actual value, the K4 relay picks up (the corresponding yellow LED lights), the
actuator must open. If the actual value is larger than the set point, the K3 relay picks up (the corresponding
yellow LED lights), the actuator must close. The control of the motor may be carried out directly via the relays
of the SRG or via an additional reversing starter unit depending on the motor type.
The reference voltage required for control and the BZL reference line are separated galvanically from the
supply. Thus, various positioners can be connected in series to the same set point (synchronization control,
split-range control).
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