Rockwell Automation 937CU-AITXF-DC1 Transmitter Supply Converter Installation Instructions - Manual (Page 25)

Bul. 937C Transmitter Supply Converter Installation Instructions
Trip and Hysteresis
When entering the values for Trip and Hysteresis please note:
• Both values are to be entered in the units, which were selected under Units.
• You can enter values
− between 0 mA and 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 hysteresis must be selected as > 1 % of the trip 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 the
operating staff.
If Alarm freeze On has been selected, the new state is maintained after 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 prevent 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 than 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.
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