Azbil Corporation
30
Model
KFPA
,
KFTA
- Field Mount type Pressure Indicating Controllers
(d) Readjustment for the zero point shift caused as above. If the shift is large, adjust
with the coarse adjusting screw (C), and achieve fine adjustment with the zero
(linearity) adjusting knob (A). Connect a suitable pressure measuring instrument to
the “X” connector on the bottom of case where the transmitted pressure is
delivered from.
5-5: Detecting element
Before starting calibrating the detecting element, make it sure that the deviation
generating mechanism has been correctly adjusted.
Set the proportional band at 100%, the reset at full open (minimum integration time),
the rate at full open (minimum derivative time) and both the PV pointer and the SP
index at 50%, move the SP index so as to make the output air pressure 50% F.S. (59.1
kPa {443 mmHg}), and set the reset at full close (maximum integration time).
5-5-1: Pressure element
Zero adjustment
Turn the adjusting knob on the travel link so that the PV pointer indicates 0% when the
element input is set at 0%.
Span adjustment
Turn the span adjusting screw so that the PV pointer indicates 80% scale when 80%
input is applied to the element. The span increases as the screw is turned clockwise.
If large change is required for the span, change the connecting position between the
travel link and the span adjustment screw hole. As the connecting position is set
farther from the center of the element, the span increases.
Linearity adjustment
(1) Check the linearity at 50% of the scale.
(2) If error more than 1% F.S. is observed adjust the travel link length by turning the
adjusting knob (F). If the error is on plus side with respect to the scale, shorten the
travel link (turn it counterclockwise as viewed from the element).
(3) The zero point will be shifted when the travel link length is changed. Re-align the
pointer to the zero scale position by loosening the zero adjusting screw.
