Calibration With Mechanical Stops - GE Masoneilan 12420 Instruction Manual & Safety Manual

7.3.4. C
ALIBRATION WITH MECHANICAL STOPS
This procedure is only possible if mechanical stops (adjusting screws) have been previosuly adjusted upon process fluids.
See mechanical stops setting Section 7.5.
This calibration procedure is very useful on site and for interface application when there is no capability to make level
variations into the tank.
a. Open the access plug (107) on the right side of the case to look at the simulation mechanism. Remove plug (190) and the
two 1/8" NPT plugs (115). Use a 5 mm Hex wrench.
b. Simulate level variations by moving the flexure (59) in the direction of the torque tube until the flexure touches the
adjusting screw post (114).
c. While maintaining contact, slide the flexure left or right along the surface of the screw post (figure 17) to simulate low and
high level values of the process fluid(s).
d. Enter [BAS SETUP] menu and the [CALIB Z S] sub-menu.
e. Enter specific gravity of calibration in level application [SG CALIB] or the low and high specific gravities in interface
application [LSG CALIB] and [HSG CALIB].
f. Low Level [ZERO]
f1. Liquid application:
Move the flexure (59) against the adjusting screw shoulder (114), which corresponds to the low level (opposite side to
the displacer). Wait for a few seconds until the displacer stabilizes.
f2. Interface application:
Move the flexure (59) against the adjusting screw shoulder (114), which corresponds to the lowest specific gravity fluid
of calibration [LSG CALIB] (opposite side to the displacer). Wait for a few seconds until the displacer stabilizes.
f3. Enter and validate the [ZERO]: the [LEVEL:%] value indicated on the display must equal 0.0%. If not, restart the
procedure until very close to this value. See Appendix B.
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CAUTION:
Calibration with adjusting screws
Masoneilan 12400 Series Transmitter/Controller Instruction Manual | 31
Figure 17