Process Unit 73 LF - Knick

NAMUR Contacts
The three NAMUR contacts functional check,
warning (maintenance required) and failure are
provided as standard.
Functional check is activated:
during calibration (),
during maintenance (): current source,
meas. point maintenance,
during parameter setting () on the
Operator level (opl) and the Administrator level
(adm),
or during an automatic rinsing cycle.
Warning (maintenance required) is activated
if a value has exceeded (or fallen below, resp.)
a preset ”Warning Limit Hi” or ”Warning Limit
Lo”, or if other warning messages have been
activated.
That means that the measuring installation is
still functioning properly but should be maintained,
or that certain process parameters have
reached a value that requires intervention.
Warning is disabled during ”Functional Check”.
Failure is activated
if a value has exceeded (or fallen below, resp.)
a preset ”Failure Limit Hi” or ”Failure Limit Lo”,
if the range limits of the Process Unit 73 LF
have been exceeded, or if other failure messages
have been activated.
That means that the measuring installation is
not properly functioning any more, or that certain
process parameters have reached a critical
value.
Failure is disabled during ”Functional Check”.
You can set the three NAMUR contacts as normally
open contacts (active: closed) or as normally
closed contacts (active: open).
For safe operation, the NAMUR contacts must be
set as normally closed contacts.
Only this ensures that power failure will activate
an alarm message!
You can define a delay time for both the warning
and the failure contact . If an alarm message is
released, the contact will only be activated after
this preset delay time.
As delivered, the relay contacts are suitable for
low signal currents (down to approx. 1 mA).
If currents above approx. 100 mA are switched,
the gold plating is destroyed during the switching
process. After that, the contacts will not reliably
switch low currents.
Capabilities 9–29