E l e c t r o n i c T e m p e r a t u r e M o n i t o r
3
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A Fan exerciser circuit will turn the Fans ON for a short time at periodic
intervals (ON time and interval is programmable).
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Automatic fan bank switching evens out the wear of Fan 1 and Fan 2 relays
by swapping their respective setpoints after each actuation.
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Operates a relay with a SPDT contact when one of the inputs exceeds the
ALARM setting. An icon on the display indicates that the ALARM is ON.
(Icon #3)
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Operates a relay with a SPDT contact when one of the inputs exceeds the
TRIP setting. An icon on the display indicates that the TRIP relay is ON.
(Icon #4). Optionally, this relay can be set to operate from internal ambient
temperature. In this mode, the “trip” relay can be used to operate as a
thermostat for heater control. Heater kit is sold separately (KIT-031-1).
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A TEST function shows the stored setpoints, shows the internal temperature
of the ETM, oil temperature, present current as % of full scale, and tests the
digital display.
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Any time the unit detects an internal or external fault such as a sensor lead
open circuit, the Alarm relay and both Fan relays operate, the FAULT icon
shows on the display and the temperature displays “- - -“. A failed sensor
will NOT cause a TRIP.
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A failed microprocessor will activate Fan 1 and Alarm relays via hardware
control.
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The Fan 1 relay is normally de-energized (non-failsafe). It will not operate
on Power Failure
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The Fan 2 relay can be configured by user to be either normally de-energized
(non-failsafe) or normally energized (failsafe). The default is normally
energized (failsafe) so that a loss of power to the ETM will turn ON one fan
bank.
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The Alarm relay is normally energized (failsafe so that an ALARM is
indicated on power failure.)
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The Trip relay can be configured by user to be either normally energized
(failsafe) or normally de-energized (non-failsafe). The default is normally
de-energized (non-failsafe) so that a loss of power to the ETM will not cause
a Trip.
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An RS-232 data port is used to setup the programmable parameters of the
unit. The setpoints and some other functions can also be set using buttons
on the front panel.
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Prime Power can be any voltage from 80-265 VAC or 20-280 VDC.
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The ETM is panel mounted through a cutout in a hinged panel of a weather
proof box
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The ETM provides the following OPTIONS, which must be specified at time
of order:
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A mA loop output may be specified which is proportional to the present
temperature. The mA loop can be set to either 0-1mA or 4-20mA via the
front panel or the RS232 port.