4-2
Zero and Span Adjustment
(1) Set the AM switch function to AUTO and set the supply pressure to 140kPa (1.4kgf/cm
2
).
(2) Remove the main cover.
On the Flame-proof version, the main cover cannot be removed while the power
is on. Move to a non-hazardous location before removing the main cover.
(3) Zero and span adjustment
(a) Apply a 0% (4mA) input signal
Rotate the zero trimmer to set the 0% output (20kPa, 0.2kgf/cm
2
). Rotating clockwise
increases the output and rotating counter-clockwise reduces the output.
(See Figure 4-2)
(b)
Next, apply a 100% (20mA) input signal
Rotate the span adjustment trimmer to set the 100% output (100kPa, 1.0kgf/cm
2
). Rotating
clockwise increases the span and rotating counter-clockwise reduces the span.
(See Figure 4-2)
(c)
Repeat the above adjustments two or three times to set the zero and span settings.
(d)
After you have finished setting the zero and span adjustment, apply a step input (25%, for
example) and check that the output is correct.
Figure 4-2
4－2
