Omega RD-MV100 Series User Manual page 37

Upper limit on rate-of-change alarm
Measured
T
value
2
T
1
t t
1 2
Interval
t -t
2 1
The interval is defined by the following equation and is set in terms of the number of
measured data points.
Interval = Scan interval × number of measurements
Alarm hysteresis
This applies to upper and lower limit alarms on measurement channels.
A width (hysteresis) can be specified on the value used to set or release the alarm. This
prevents the alarm from being set or released repetitively when the measured value is
fluctuating around the alarm value. The hysteresis is fixed to 0.5% of the display span
(display scale if the range is set to [Scale]). The initial setting is [ON].
Upper Limit Alarm (H)
Alarm occurrence
1V
Alarm release
Measured value
Lower Limidt Alarm (L)
Measured value
1V
Alarm occurrence
Alarm output relay
If you are using a model with the optional alarm output relay (/A1 through /A3), a contact
signal can be generated according to the alarm conditions. For the procedure related to
setting the alarm output relay, see section 6.2, "Alarm Setting."
The following functions can be specified on the alarm output relay. For details, see
section 6.4.
• When multiple alarms are set to one alarm output relay, notify the succeeding alarms
after the first alarm that causes the relay operation (reflash alarm function).
• When multiple alarms are set to one alarm output relay, operate the relay when all
specified alarms are active (AND function)
• Energize or de-energize the alarm output relay when the alarm occurs (energize/de-
energize function of the output relay).
• When the alarm changes from the ON state to the OFF state (return to normal
condition), turn OFF the output relay with an alarm ACK operation (output relay hold
function).
Lower limit on rate-of-change alarm
R alarm
T
1
Measured
value
Variation
T
2
|T -T |
2 1
Time
Alarm set point
Hysteresis (approx. 0.5%)
Alarm release
Hysteresis (approx. 0.5%)
Alarm set point
1.5 Alarm Function
Variation
|T -T |
2 1
r alarm
t t Time
1 2
Interval
t -t
2 1
1-19
1