Chromalox 3901 User’s Manual
11
Remote
Alarm Reset
The Remote Alarm Reset works exactly like the Alarm
Reset function described above, except that the relay
is reset by pushing a remote momentary switch that
has been connected to terminals 3 and 4 (see page 7
for wiring).
Set Point
Limit
Adjust Set Point Limit—The 3901 has a set point
limit feature that allows you to preset an upper limit
for the set point adjustment. The set point limit can be
used to prevent an operator from selecting a set point
which could damage the process, product or
equipment.
The set point Limit is set at 100% of sensor span when
shipped from the factory (i.e. 1000
°
F for Type J
thermocouples and 2000
°
F for Type K thermocouples).
An internal potentiometer allows you to adjust the set
point limit from a range of 100% to 20% of sensor
span. To adjust the set point limit, remove the back
cover of the 3901 as described on page 4. Locate the
set point limit potentiometer shown in Figure 3.2.
USE EXTREME CAUTION: The set point limit can
be set with the instrument power to the controller
either off or on. If the power is left on, the limit must
be adjusted only by a qualified electronic technician at
a test bench, using an insulated screwdriver.
CAUTION:
LINE VOLTAGE WILL BE EXPOSED!
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