Barksdale 9671 Series Operating Instructions Manual page 4

In pressure switches, a displacement of the pressure sensing element occurs with a change in
pressure. Following the displacement of the pressure sensing element operates a microswitch.
Upon delivery of the product, the set points are likely to be found in the middle of the adjustable
range. On request, fix set points may be adjusted by our factory. In this event, the point will be
indicated on the type plate or any separate plate, i = increasing, d = decreasing.
The set point is adjusted by turning the adjustment screw.
IMPORTANT
To reach the adjustment screw for pressure switches with housing, remove the cover (see Fig. 7
or Fig. 8).

Allow pressure switch to reach the desired switch pressure.

Turn adjustment screw clockwise or counterclockwise to actuate the micro switch.
IMPORTANT
In case of overpressure: + –
IMPORTANT
Please consult the wiring diagram for the contact status at atmospheric pressure (see Fig. 5).
Precise adjustment of set point to actuate on increasing pressure

Lower system pressure to 0 bar.

Increase pressure slowly and check if micro switch is actuated at desired switch pressure.

If necessary, readjust by turning the adjustment screw

Repeat the previous steps until the micro switch operates at the desired switch pressure (if
necessary check and readjust once again on the following day).
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Counterclockwise rotation: set point increasing
Clockwise rotation: set point decreasing
Precise adjustment of set point to actuate on decreasing pressure

Increase pressure up to a point clearly above the desired switch pressure
pressure plus max. hysteresis; not above max. operating pressure).

Lower pressure slowly and check if micro switch is actuated at desired switch pressure.

If necessary, readjust by turning the adjustment screw

Repeat preceding steps until microswitch operates at desired switch pressure.

Following the adjustment of all set points, each set point must be checked again and, if
necessary, readjusted. (If necessary, check and readjust the set points once again on the
following day.)
IMPORTANT
The adjustment of several set points occurs for each set point as specified above.
Wiring Code for all Types (Contact status at atm. pressure)
c

NC
NO
c
NC 
NO
at vacuum NC/NO vice versa
Fig. 5: Wiring Code
Wiring code/Option
Pressure 9681X/9692
Function Circuit 1 Circuit 2
Normally red yellow
Open/NO
Common/C purple brown
Normally blue orange
Closed/NC
Earth green
(at least, switch
Power circuit  Power circuit 
C = purple C = brown
NC = blue NC = orange
NO = red NO = yellow
Vacuum 9671X Option
Circuit 1 Circuit 2
blue orange K with mounting
holes
purple brown
red yellow
green
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