Samson 3767 Mounting And Operating Instructions page 45

Zero point adjustment
1. Use the input signal of the positioner to
move the valve to closed position (valve
CLOSED, travel 0 %).
2. The ammeter must now indicate approx.
4 mA.
3. Correct smaller deviations at the ZERO
potentiometer until the meter shows ex-
actly 4 mA.
For larger deviations that cannot be cor-
rected using the potentiometer (adjust-
ment range of approx. 20 turns), set the
switches 1 and 2 to indicate an mA val-
ue which is within the adjustment range
of the ZERO potentiometer.
4. Set the zero point to exactly 4 mA using
the ZERO potentiometer.
EB 8355-2 EN
Adjusting the span
1. Use the input signal of the positioner to
move the valve to closed position (valve
CLOSED, travel 100 %).
2. The ammeter must now indicate approx.
20 mA.
3. Correct smaller deviations at the SPAN
potentiometer until the meter shows ex-
actly 20 mA. If deviations are too high,
set the switches 3 and 4 to indicate an
mA signal which is within the adjustment
range of the SPAN potentiometer.
4. Turn the SPAN potentiometer until the
ammeter shows exactly 20 mA.
Since the zero point and span have a
mutual influence on each other, repeat
the correction procedure at both potenti-
ometers until both values are correct.
Operation
45