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BULLETIN F-56
2) CONCENTRIC - Adjust Range Spring active coils by loosening Range Spring Locknut and turning
Range Spring. Four to four and one-half active coils are desired for a standard input span.
SEPARATE - Adjust Range Spring active coils by loosening Range Spring Lockscrew and turning
Range Spring. Four to four and one-half active coils are desired for a standard input span.
3) CONCENTRIC - Tighten Fine Zero Locknut and Range Spring Locknut after making adjustment.
SEPARATE - Tighten Fine Zero Locknut and Range Spring Locknut after making adjustment.
3. Turn on supply pressure.
4. Zero Adjustment
A. Fine Zero Adjustment
1) Set input signal to desired minimum range value.
2) Loosen Fine Zero Locknut.
3) Turn Fine Zero Thumbwheel until desired valve position is reached and tighten Fine Zero
Locknut.
If Positioner can not be zeroed, proceed to Coarse Zero Adjustment. Otherwise proceed to
step 5 Span Adjustment.
B. Coarse Zero Adjustment
1) Center fine zero adjustment by loosening Fine Zero Locknut and turning Fine Zero Thumbwheel
so that approximately one thread (1/16˝) of the Fine Zero Screw projects above Fine Zero
Thumbwheel.
2) Loosen Coarse Zero Lockscrew 1/4 turn. The Span Nut must be tight against the spring.
3) CONCENTRIC - Turn Coarse Zero and Span Nut and Fine Zero Thumbwheel simultaneously in
the same direction until valve is in desired position. Continue to turn Coarse Zero and Span
Nut until Coarse Zero Lockscrew and Range Spring Locknut are accessible.
Bulletin F-56 6/27/05 9:37 AM Page 18
