Arroyo Instruments TECSource 5400 Series - Applying Sensor Limit Conditions; Temperature Protection Logic

5400 Series TECSource User’s Manual · Page 33
Applying Sensor Limits
With the wide range of sensor connectivity options, the 5400 is designed with a
series of temperature protection limits and options to allow for flexibility when
meeting the demands of different applications.
Each sensor has a dedicated high and low temperature limit, which can be
found in the Sensor Limits menu. When the temperature input exceeds these
limits, that sensor is considered to be in limit, either high or low. Limit conditions
are also activated when the sensor is open. For thermistor and AD590 sensors,
an open circuit will trigger a low limit, while all other sensors will trigger a high
limit.
How the instrument reacts to these limits depends on four menu settings, all of
which can be found in the Out Off Menu:
 Thi Limit
 Tlo Limit
 Apply Nonactive
 Apply Aux
Apply Nonactive is used to include the temperature limits of the non-active
primary sensors when determining if a temperature limit condition exists. When
set to Yes, non-active primary sensors in limit will cause a temperature limit
condition. If No, non-active primary sensors will not be used in determining if a
limit condition exists.
Similarly, Apply Aux is used to include the temperature limits of auxiliary sensors
when determining if a limit condition exists. When set to Yes, if any auxiliary
sensor in limit will cause a temperature limit condition. If No, auxiliary sensors
will not be used in determining if a limit condition exists.
By default, Apply Nonactive and Apply Aux are set to No, which means only a
temperature limit of the active sensor will cause the temperature to shut down.
Once a determination is made that a temperature limit condition exists, the Thi
and Tlo Limit settings control if the output will be shutdown. If set to Yes and an
appropriate high or low limit condition exists, the output will be turned off.
In all cases, limits are only applied to enabled sensors. When a sensor is set to
Disabled, it will not be evaluated for limit conditions.