Samson 3767, Mounting And Operating Instructions

Page: 42 / 68

42 EB 8355-2 EN
Operation
5.3 Adjusting the limit contacts
The positioner version with inductive limit
contacts has two adjustable tags mounted on
a rotary shaft which operate the associated
proximity switches (50).
The operation of the inductive limit contact
requires switching amplifiers to be connected
in the output circuit. Refer to section 4.2.1.
When the tag (51) is located in the inductive
field of the switch, the switch assumes a high
resistance. When it moves outside the field,
the switch assumes a low resistance.
The limit contacts are usually adjusted to is
-
sue a signal for both end positions. The
switching points can also be adjusted to in-
dicate intermediate positions.
The switches A and B must be assigned to
the end positions of the control valve (valve
OPEN or CLOSED) depending on the oper-
ating direction and the mounting position ac -
cording to Table 8 and Table 9.
The terminals 41/42 and 51/52 can option-
ally be assigned to the switches A and B by
turning the associated label on the terminal
block (also see Fig. 12).
NOTICE
The tags of the limit contacts cannot
be turned by 360°. As a result, it is
important to observe the correct as-
signment of switches A and B to the
valve positions (valve CLOSED and
valve OPEN), especially when the
limit contacts are to be connected in
safety circuits.
The required switching function, i.e. whether
the output relay is to be picked up or re-
leased when the tag enters the field, must be
determined at the switching amplifier.
Fig. 14: Limit contacts