Calibration - Baker Hughes Masoneilan 496 Series Instruction Manual

8.

Calibration

Before power up the device to proceed with
calibration carefully read the following safety
warnings.
– Comply with current national and local
regulations for electrical installation
work.
– Must be installed and put into service in
conformance with EN 60079-14 and / or
national and local regulations applicable
for explosible atmospheres.
– Before carrying out any work on the
device, power off the instrument or
make sure
that the local conditions in the
potentially explosive atmosphere
permit- the safe opening of the cover.
– Connect the wires to the instrument's
terminals, taking care of complying
with polarities and maximum voltage
allowed.
– Before power up or after doing any work
on the device always check the cover (12)
is fully screwed, O-ring (10) is free of any
damage and security screw (9) is well
locked.
8.1 Calibration of rotary limit switch
496-157, 496-257, 496-158 and
496-258
• The concave portion of the lever (5) must be
strictly concentric to the cam (13) when the
micro-switch is actuated.
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• This is an important caution to make sure the lever is
properly depressed when not actuated.
• If not, loosen the screws (3 & 17) and slightly move
the lever upwards or downwards. Tighten the screws.
• Slightly loosen the cam locking screw (1) using a
3/32" socket hex head wrench.
• Move the plug stem to the position required to actuate
the switch.
• It is important to note that the cam operating the right
hand micro-switch must actuate the lever (5) at the
end of the counterclockwise rotation. (See detail figure
below).
• This makes sure the screw (2) has free the lever (5)
when the valve is throttling. The remaining concave
portion only ensures micro-switch actuation in case of
over travel. Conversely, the cam operating the left
hand micro-switch must actuate the lever (5) at the
end of the clockwise rotation. (See front view below).
• To meet the above requirement when only one micro-
switch is provided (type 496-158) it may be necessary
to change the location of the micro-switch.
• Rotate the cam (13) until the micro-switch is actuated.
Lock the cam (13) tightening the screw (1).
• Fine tune adjustment with screw (2). Use a 1/16"
socket hex head wrench. The screw (2) must come
out the cam enough to properly depress the lever (5).
• Strictly follow safety instructions under §7.4
before putting into service.
Masoneilan 496 Series Position Transmitter ATEX Instruction Manual | 15