Four Channel Temperature Alarm - doc00032
Description :
The temperature
in a pipe is monitored with four RTD Pt-100 Sensors, The type of probe
could
be Extruder RTD probes with Bayonet or Compression Fitting, Get it
from Omega. To keep costs
low you can choose small thin film RTD sensors, they will be fast but
on rough usage may break.
The temperature at four points are measured by Temperature Module and
compared with
one common setpoint 0-200 deg F, an alarm output LED out-a goes
ON when the measured
temperature exceeds the common setpoint.
The time taken to measure the temperature at the 4 points will be less
than 4 seconds. An optional display of the measured temperature
as shown above can be avoided by using a DMM to adjust the setpoint.
The Analog Timer Module can be set from 0- 30 minutes. If out-a
remains high even after set time a out-b alarm goes on to sound a
buzzer and flash a LED light.
A
digital timer is avoided so as to keep costs low, The alarm is
audio-visual,
piezo electric buzzer for sound and a flashing red big 10mm LED for
visual
annunciation, a digital output is also given to turn on an optional SSR
to
power a hooter or to turn off something.
Whenever out-a goes
high and low the Counter Module counts from 0000 to 9999. The counter
can
be reset at any time by pressing a button. This will count the number
of
times temperature in pipe went above the setpoint.
The unit is powered by a 9V battery to backup the counts in counter
module, The LED displays are turned on by a pushbutton for momentary
use to extend battery life.
Block Diagram :

Resources :
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