Interlock A Menu - Walchem WDP420 Instruction Manual

5.6

Interlock A Menu

This menu only appears in WDP models.
The Interlock A menu is used to assign an interlock device to the appropriate sensor. An interlock
device is an external monitoring sensor like a flow or level switch that serves to deactivate control
outputs when activated. For example, this could be used to prevent the controller from pumping
chemicals based on a stagnant sample.
The WDP controller can support up to two interlock devices. Refer to Figure 3c and d for a wiring
illustration. A typical setup would use one flow switch for sensor A and one for sensor B and they
would function independently. This is the default setting and describes operation when Sensor A Only
is selected in this menu.
However, in some applications it is desirable to have one interlock device assigned to both sensor A and
B. For example, if you have both sensors mounted in the same sample stream, then a flow switch input
could be used to disable control for both sensors. This describes the operation when Sensor A and B is
selected in this menu. Note: If this type of operation is desirable, the single interlock device must be
connected to the Sensor A input as illustrated in Figures 3c and d.
To make a selection, press
between Sensor A Only and Sensor A + B. Press
to change the selection. Press
7.00pH
Interlock A
EXIT ENTER
Assign Intrlk A
Sensor A Only
Assign Intrlk A
Sensor A and B
ENTER at the Interlock A menu. Use the UP or Down keys to toggle
EXIT to return to the higher level menu.
77°F
Operation
A
A
Figure 12 Interlock A Menu
again when the desired choice is displayed
ENTER
Interlock A Menu
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