How To Select the Trip Point Action Cha
ter Four: O
eration
38
Refer to Figure 6, page 21, for the location of the trip point adjustment pots. Turning the
pot clockwise raises the trip point setting.
7. Repeat steps 1 and 2 to adjust TP B.
8. Slide the enclosure over the unit and press it in place.
9. Attach the hex nuts, removed in step 3, to the I/O connector.
10. Reconnect the leads and wires.
Refer to
How To Select the Trip Point Action,
page 38, to change the action of the trip points.
How To Select the Trip Point Action
Equipment required:
3
/
16
” hex or open-ended wrench
The 649 controller is initially configured with TP A set to trip high (it is on when the pressure is
above
the trip point pressure) and TP B set to trip low (it is on when the pressure is
below
the trip
point pressure). To change the action of the trip points you must remove the cover of the unit
and change jumpers on the Transducer board. Each trip point has a jumper block with the
jumper positions labeled TL (trip low) and TH (trip high).
1.
Stop the gas flow through the 649 controller.
2.
Remove any leads or wires attached to the connector on the 649 controller.
3.
Use a
3
/
16
” hex wrench (or open-ended wrench) to remove the hex nuts on each side of
the I/O connector.
Refer to Figure 6, page 21, for the location of the hex nuts on the I/O connector. Place
the hex nuts aside for safe keeping.
4.
Position the controller with the front side facing you, and pull up on the enclosure to
remove it.
The board assembly will be visible, with the Transducer board facing you and the
Control board behind it.
5.
Locate the jumper blocks labeled “JP4” and “JP3” in the middle of the Transducer board.
Refer to Figure 14 for the location of the jumper blocks.
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