
TEMPERATURE MONITORING EXAMPLE
An IMY is installed as a monitoring device and back-up
controller for a freezer storage facility. Normally, the
freezer temperature is maintained at about -29°C ±2°. The
absolute maximum allowable temperature of the freezer is
0°C. In the event of a system failure, alarm output #1 of the
IMY is programmed to start a secondary cooling system
should the temperature reach 0°C. The additional alarm of
the IMY is used to signal personnel with a warning bell
when the temperature rises above -17°C (indicating a
possible failure of the main cooling system). This alarm is
programmed to latch in order to assure that personnel
inform maintenance of a possible problem. Key switches
are installed to lock out the front panel from unauthorized
personnel and to provide a means of resetting the latched
alarm. The Integrator/totalizer option is specified to store
peak and valley temperatures overnight, weekly, etc.
Programming module #5 (Pro 5) is used to set up the
integrator. The re-transmitted analog output is specified to
drive a chart recorder with 4-20 mA for a hard copy of
temperature profiles for later evaluation.
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