Samson 4785, Монтаж и эксплуатация

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4.5 Adjusting the inductive limit
switches
The positioner version with inductive limit
switches has two adjustable tags which are
mounted on the shaft of the positioner lever
and operate the associated proximity switches.
For operation of the inductive limit switches,
the corresponding switching amplifiers have
to be connected to the output circuit (see sec-
tion 3.2.2).
If the tag is in the inductive field of the
switch, the switch assumes a high resist-
ance. If the tag is outside the field, the
switch assumes a low resistance.
Normally, the limit switches are adjusted
such that they will provide a signal in both
of the valve’s final positions. These switches,
however, can also be adjusted to signal in-
termediate valve positions.
The desired switching function, i.e. whether
the output relay shall be picked up or re-
leased when the tag has entered the field,
must be selected at the switching amplifier,
if required.
Adjusting the switching point:
The limit switches are marked GW1 and
GW2 on the inside of the case cover. Yel-
low tags and the associated adjustment
screws (Fig. 11) are located below these
markings.
Each switching position can optionally be sig-
nalled either when the tag has entered the
field, or when it has left the field.
Move the valve to the switching position
and adjust the tag of the required limit
switch GW1 or GW2 by turning the re-
lated adjustment screw until the switching
point is reached. This is indicated by the
LED at the transistor relay.
In so doing, one edge of the yellow tag will
be aligned with the white, horizontal line on
the case cover. This indicates the side from
which the tag enters the inductive field of
the proximity switch.
To ensure safe switching under any ambient
conditions, the switching point is to be ad-
justed to a value of approx. 5 % before the
mechanical stop (OPEN - CLOSED).
36
EB 8382-2 EN
Adjusting the inductive limit switches