Process Unit 73 LF - Knick

Process Unit 73 LF
How does probe rinsing operate?
The rinsing equipment is controlled via three contacts:
Contact ”probe”:
This contact can be set as normally open or
normally closed. It controls a process valve in a
flow-through fitting, for example. In measuring
mode the contact is deactivated. During rinsing
cycle it is active to close the process valve, for
example.
Contact ”rinsing”:
can control the valve for the rinsing medium.
The contact is closed during first and second
rinsing.
Contact ”cleaning”:
can control a valve for the cleaning liquid. The
contact is closed during cleaning.
The three contacts are electrically connected on
one side.
If the Process Unit is equipped with option 352
probe rinsing, the current input is used for remote
control of the rinsing cycle (see page 9–43):
0 – 10 mA (normal operation):
A current in this range permits start of rinsing
cycle by user defined interval or manually in the
menu.
10 – 20 mA (start):
A current in this range starts a rinsing cycle.
The current must be applied for at least 2 s.
As long as this current is applied, the probe remains
in wait position. That means: rinsing lead
time, first rinsing, cleaning, and second rinsing
are executed. Then the probe remains in wait
position. When the current is removed, the
cycle will be continued with measurement lead
time.
> 20 mA (lock):
A current in this range locks start of a rinsing
cycle independent of the user defined interval.
9–46 Capabilities