Four Channel Temperature Alarm - doc00032
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
See another Solution that is about - Temperature
Meters with Analog Recorder Output
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 Source design files for this project are here -
Channel Temperature Alarm Docs
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
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 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.
elements, industrial heaters.
Watlow is the largest custom designer and
manufacturer of industrial electric heaters, sensors
Beginners Guides to Measurement - Temperature
The accurate measurement of temperature is vital
across a broad spectrum of human activities,
including industrial processes (e.g. making steel),
manufacturing; monitoring and in health and safety.