Installation Instructions Manual

Bul. 937C Transmitter Suppl
y Converter Installation Instructions
Trip and Hysteresis
When enterin
g the values for Trip and Hysteresis ple
ase
note:
• Both values are to be entered in the units, which were selected under Units.
• You can
enter values
−
between
0
mA a
nd
24
mA
and
- between the converted values of these limits in the selected units; for conversion using the
parameters Zero point and Conversion factor.
• The h
ysteresis must be selected as >
1 %
of
the tr
ip
point to prevent the relay from vibrating.
•
As the representation of the operating behaviour, the following must apply:for the switching direction
Max: Trip point - Hysteresis > 0
− for the switching direction Min: Trip point + Hysteresis < upper limit trip point
These input limits are automatically preset by the transmitter supply converter.
Alarm freeze
The Alarm freeze helps you to avoid that short-term trip value overranges are not noticed by th
e
operating staff.
If Alarm freeze On h
as been selected, the ne
w state
is
maintained a
fter
the relay switching until the ESC key is
pressed or the device is restarted. These actions reset the relay, except for a limit violation.
Delay
If you set a time > 0 sec, you preven
t short-time violations of
the trip value from triggering an alarm.
• The relay only switches if the trip point is exceeded/fallen short of for a period that is longer th
an the
delay
time.
• The relay only switches back if the trip point -/+ hysteresis is fallen short of/exceeded for a period
that is longer than the delay time.
• If the trip point is exceeded/fallen short of for a short time, this does not have any effects.
23