6
45
6 - Controllers
Set the desired day and night o temperatures for pumps,
and a time delay for restarts. The restart delay prevents
the pumps starting and stopping in response to slight vari-
ations in the outdoor temperature. Important: The delay
is used every time the controller starts for any reason, for
example after a power cut.
Specify the deviation, delay, hysteresis and alarm details
for set value deviation. The deviation is the maximum permitted dierence between the actual
value and the set value before the alarm is triggered. The delay is the number of seconds the de-
viation is tolerated before the alarm is triggered. Hysteresis is the number of degrees by which the
deviation must fall below the alarm threshold before the alarm is deactivated.
Choose an email option and select the alarm type. The alarm type determines how the WMPro will
handle an alarm. There are three options.
Automatic reset, no acknowledge. There is no need to
acknowledge this alarm type. The alarm is recorded in the
alarm log and emails are sent (if email notication is ena-
bled). Otherwise everything continues as normal.
Automatic reset, with acknowledge. As above, except that
the alarm remains active until it is acknowledged.
Reset when acknowledged. Choose this option if the alarm
performs an action in WMPro, for example frost protection
in a ventilation system. If there is a risk of freezing, the system is stopped and cannot restart until
someone acknowledges the alarm.
P-area
The P-area denes the devia-
tion necessary in order to obtain
a 100% output signal from the
controller. The P-area is centred
on the set value, so if the P-area
= 10 K and the set value is 20 °C,
the output signal is 50% when the
actual value is 20 °C. When the
actual value is 15 °C the output
signal is 100% and when it is 25 °C
the output signal is 0%.
I-time
The I-time is the time taken to
halve or double the control signal
for a specied constant deviation.
For example, assume that a devia-
tion produces a 20% output signal.
After one I-time the output signal
is 40%. After two I-times the out-
put signal is 60%. And so on. The
deviation must remain constant
throughout.
Alarm types
You can choose from three dier-
ent types: automatic reset without
acknowledgement; automatic
reset with acknowledgement; and
restart when acknowledged. You
can nd out more in section 7.
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