Input Signal - Samson 3374 Mounting And Operating Instructions

Configuration level

13.2 Input signal

The input signal determines the actuator stem position. Either a current or voltage signal can
be applied to the input. The default lower and upper range values of the input signal are 2 to
10 V or 4 to 20 mA. The input signal range can be adapted, e.g. to achieve a plant opera-
tion characteristic by connecting two or more actuators in parallel (split-range operation).
Example: Two valves regulate the process medium in one common pipeline to achieve a
large rangeability. One valve opens with a 0 to 5 V input signal, while the second valve also
opens when the input signal increases further (5 to 10 V) and the first valve remains open.
The two valves close in the reverse order.
Note:

At least 2.5 V or 5 mA (depending on the input signal used) must separate the upper
and lower range values.
Code Description
c01 Unit
c02 Lower range value
c03 Upper range value
Detect input signal failure
The actuator detects a failure of the input signal and the error reading E01 starts to blink on
the display as soon as the input signal falls below the lower range value by 0.3 V or
0.6 mA. If the input signal failure function is active (c31 = YES), the reaction of the actuator
upon failure of the input signal is determined by Code c32:
− Internal travel value (c32 = INT): The actuator stem moves to the position specified in
Code c33 upon failure of the input signal.
− Last travel value (c32 = LAST): The actuator stem remains in the last position that the
valve moved to before failure of the input signal.
The error message is reset and the actuator returns to closed-loop operation if the input sig-
nal moves within 0.2 V or 0.4 mA of the lower range value.
38
WE Adjustment range
mA mA (current signal),
V (voltage signal)
2.0 V or 0.0 to 7.5 V or
4.0 mA 0.0 to 15.0 mA
10.0 V or 2.5 to 10.0 V or
20.0 mA 5.0 to 20.0 mA
EB 8331-4 EN