Measuring Element Replacement; Pressure System - ABB Fulscope 76J Series Model C Instructions Manual

76J Pneumatic Fulscope Recorder
MAINTENANCE
3. Repeat Zero, Span and Linearity adjustments for required accuracy.
* NOTE:
4.5

MEASURING ELEMENT REPLACEMENT

4.5.1

Pressure System

1. Turn off all electrical power to recorder.
2. Remove chart plate and connecting link, Figure 13.
3. Disconnect piping to measuring element.
4. Remove screws and move terminal block to disconnect measuring element. If case fitting
is part of measuring element, disconnect case fitting from access plate. Remove access
plate to remove element. Refer to Figure 17.
Low pressure bellows element inputs may be disconnected at the bellows element without
disturbing case fittings or terminal block. Figure 14A.
5. Remove measuring element base screws and element.
6. If input piping to element is behind chart motor, remove motor.
* NOTE:
7. Install replacement element in case making sure horizontal position is indexed to
previously scribed mark.
8. Connect measuring element link.
9. Install case fitting, piping, access plate, terminal block, chart motor, and wiring if removed.
10. Proceed to 4.4 Pen Calibration for preliminary information and 4.4.3 Zero Adjustment to
touch-up micrometer screw.
11. Verify span and linearity adjustments.
26
Changing hole selection from hole No. 1 to No. 6 changes linearity
approximately 2%. If link appears to be too long or short, it may be
necessary to move measuring element for additional correction as
follows:
With 50% input, loosen measuring element mounting screws and slide
element in the same direction as the pen should move to read correctly.
Tighten mounting screws.
Repeat Zero, Span and Linearity adjustments.
The replacement pressure element has been factory calibrated with a
specific link length and pivot selection. Use this Link on the New
Element and Refer to Yellow Instruction Tag for Important
Information, Figure 18.