Rockwell Automation 937CU-AISTR-DC1 Strain Gauge Converter Installation Instructions - Manual (Page 30)

Bul. 937
C Strain Gauge Converter Installation Instructions
• As the representation of the operating
behavior in section 7.6.2 shows, the following must apply:
− for the trip mode Max: trip point - hysteresis ≥ 0
− for the trip mode Min: trip point + hysteresis ≤ upper limit of the trip point
The limits are automatically determined by the
Strain Gauge Converter being.
• The hysteresis should be > 1 % of the trip point in order to prevent rapid switching of the relay.
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.
The following figure shows the operating
behavior for the trip mode Max, operating mode Active.
Time
Trip mode Max, operating mode Active, with delay
energised
de-energised
Delay Delay
Max - hysteresis
Max
Measured
value
28