V5.00
25832_EDEBD
A0289-5020-1_EN
37
The result is the following:
The contact switches if the cumulated power is greater than 90 kW
(90% of the target value) and the message
I20 prewarning contact
active is issued.
No hysteresis is available, as the cumulated power only increases during the measure-
ment period.
The contact remains switched until the measurement period ends.
It drops at the beginning of the next measurement period because the cumulated power
restarts below the warning threshold.
However, the prewarning contact is not deactivated if the minimum on time has not yet
elapsed.
The message
E20 prewarning contact active
is issued when the contact is switched off.
When a measurement period is first started, the
prewarning contact function is locked for the first 10 minutes (measurement period time-
out). This means that the prewarning contact is not active or is deactivated (if the contact
was active at the end of the previous period and no minimum on time is applied).
The measurement period time-out is always started at the beginning of a measurement
period. The minimum on and off times take priority over the measurement period time-
out.
Programming example:
Function type: Trend power greater than power warning threshold
Prewarning contact active
TYPE
Ptrend > Pthresh
Warning threshold
In % of active target value
90 percent
Hysteresis
in kW
10 kW
Minimum on time
in minutes
0.5 minutes
Minimum off time
in minutes
1.0 minutes
Period time-out
in minutes
10 minutes
Prewarning contact address A 48
Cannot be changed
Currently-active period target value: 100kW
Warning threshold:
90% (corresponds to 90 kW)
Hysteresis:
10
kW
Minimum on time:
0.5 minutes (corresponds to 30 seconds)
Minimum down time:
1.0 minutes (corresponds to 60 seconds)
Period
time-out:
10.0 minutes
Description of parameters