Samson 3767, Mounting And Operating Instructions

Page: 44 / 68

44 EB 8355-2 EN
Operation
5.4 Adjusting the position
transmitter
NOTICE
The starting point (zero) and upper
range value (span) must be set before
adjusting the position transmitter.
Depending on the position of the multi-pin
connector (symbol on connector: >> or <>),
the feedback signal can be set to either a
range of 4 to 20 mA or 20 to 4 mA for 0 to
100 % travel.
Fig. 15: Position transmitter
Zero point
Use the switches 1 and 2 to roughly set the
zero point and the ZERO potentiometer for
fine-tuning. The adjusted value is always
based on a 4 mA signal.
Span
Use the switches 3 and 4 to roughly set the
span, i.e. the upper range value, and the
SPAN potentiometer for fine-tuning. The ad-
justed value is always based on a 20 mA
signal.
Example:
Move the valve to the open position while
observing the position transmitter signal.
If the signal does not move in the desired di -
rection, change the position of the multi-pin
connector.
Adjust the zero point (4 mA) and span
(20 mA) for the valve positions according to
Table 10.
Table 10: Position transmitter
Valve movement Observed feedback signal Direction of signal Set zero/span to
OPEN
á
CLOSED
Signal increases
á
OK
20 mA Valve OPEN
4 mA Valve CLOSED
Not OK
à
Change connector's
position
4 mA Valve OPEN
20 mA Valve CLOSED
Signal drops
â
OK
4 mA Valve OPEN
20 mA Valve CLOSED
Not OK
à
Change connector's
position
20 mA Valve OPEN
4 mA Valve CLOSED