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ment clockwise to increase the span. Adjust the
span adjustment screw to correct for half of the
error.
b. If the pointer indicates greater than the process
scale upper limit, rotate the pointer span adjust-
ment counterclockwise to decrease the span. Ad-
just the span adjustment screw to correct for half of
the error.
13. Repeat steps 9 through 12 until the zero and span
indications are within 1 percent of the scale limits
with no further adjustment. If the span adjustment
screw is adjusted to its limit and the span is still too
short or too long, proceed with step 14. If proper span
is achieved, proceed to step 16.
14. Within the process pointer subassembly, there are
three holes for the connection of link 1. Use procedure
(a.) or (b.) below to make the coarse span adjustment
with link 1.
a. If the span is short (process pointer indication is
less than the process scale upper limit), disconnect
link 1 from the process pointer subassembly, move
the link to the lowest hole (the hole nearest the
pointer pivot), and return to step 9. If the link is al-
ready in the lowest hole, proceed to step 15.
b. If the span is long (process pointer indication is
greater than the process scale upper limit), discon-
nect link 1 from the process pointer subassembly,
move the link to the highest hole (hole furthermost
from the pointer pivot), and return to step 9. If the
link is already in the highest hole, proceed to step
15.
15. At either end of link 5, there are four holes in
which the link may be connected. A coarse span ad-
justment can be made by moving both ends of link 5
up or down.
a. If the span is short (process pointer indication is
less than the process scale upper limit), disconnect
both ends of link 5, move the link down one set of
holes, and return to step 6.
b. If the span is long (process pointer indication is
greater than the process scale upper limit), discon-
nect both ends of link 5, move the link up one set of
holes, and return to step 6.
16. Apply process differential pressure equal to the
mid-scale value of the process scale span. The pro-
cess pointer should indicate mid-scale 2 percent of
the scale span. If the process pointer error is 2 per-
cent or less, proceed to step 17. If the process pointer
error exceeds 2 percent, the linearity can be im-
4194A, B, and C Series
proved with the linearity adjustment. See figure 5-17
for the linearity adjustment screw location.
a. If the error at mid-scale is high (process pointer
is to the right side of the mid-scale mark), loosen
the linearity adjustment screw and slide it upward in
the curved slot. Tighten the screw and return to
step 6.
b. If the error at mid-scale is low (process pointer
is to the left side of the mid-scale mark), loosen the
linearity adjustment screw and slide it downward in
the curved slot. Tighten the screw and return to
step 6.
17. Adjust the process pointer to within 1 percent of
the mid-scale mark by loosening the zero adjustment
locking screw and adjusting the zero adjustment
screw. Tighten the zero adjustment locking screw. This
distributes the error over the entire process scale and
keeps all points within 1 percent of the process scale
span.
18. Adjust the process differential pressure to the low-
er and upper limits of the scale span to make sure the
process pointer is still within 1 percent of the lower
and upper scale limits.
19. Perform the flappper alignment procedure and, if
necessary, the appropriate remote set point calibration
procedure in section 3 or 4.
Remote Set Point (suffix letter M)
Maintenance
Replacing the Remote Set Point Assembly
Use the following procedures to replace the remote set
point assembly. Figure 5-20 shows the parts locations.
Refer to figure 5-26 for key number locations.
Remove the supply pressure gauge be-
fore attempting to remove the remote
set point assembly.
1. Decrease the remote set point pressure to 0 psig.
2. Remove the supply pressure gauge.
3. Remove the pressure connection (key 93 at the
pedestal assembly (key 105). Use two 5/16 inch
wrenches.
4. Disconnect link B (key 126) from the connection
hole on the set point indicator.
5. Remove the three mounting screws (keys 120 and
140) that attach the remote set point assembly to the
process/set point indicator assembly. Figure 5-20
shows the mounting screw locations.
Note
5–25
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