Vaisala DM500 - Manual (Page 80)

User's Guide ______________________________________________________________________
78 __________________________________________________________________ M210205EN-D
7. Select Active below: xx , press SET . Set the value below which you
want the relay to be released. Use the numeric buttons. Press
OK .
When the measured value is in between the above and below
values, the relay is passive. When choosing lower value as
above value and higher value as below value the relay is passive
when the measured values is not between the set values. You
can set only one value or remove both setpoints by pressing
DELETE . If both setpoints are removed the state of the relay
changes on the basis of the measurement status, see further
instructions.
8. Select HYSTERESIS , press SET . Set the value by using numeric
buttons. Press OK .
Relay is activated when the measured value passes the setpoint.
As returning and passing the setpoint again relay is released
only until the value is reached the setpoint decreased/increased
by the hysteresis value.
Hysteresis function is to prevent the relay switching back and
forth when measured value is not stable near to the set point
values given.
Example: when the active above value is +20 ºC and the
hysteresis value is 2 ºC, relay changes state when the dewpoint
reaches 20 ºC. When the dewpoint decreases, relay changes state
at 18 ºC.
9. Select ENABLED WHEN , press SELECT . Now you can select the
measurement status that enables function of the relays.
10. Set the measurement status that determines when the relays are
enabled. Relay changes state on the basis of the measurement
status if there are no setpoints determined. If the setpoints are
determined the relay changes state on the basis of the setpoint
when the selected measurement status is active. Otherwise the
relay is disabled.
STOP: relay is enabled when dewpoint measuring status is
STOP
ERR: relay is enabled when dewpoint measuring status is ERR
OK: relay is enabled when dewpoint measuring status is OK.
WAIT: relay is enabled when dewpoint measuring status is
WAIT.