APPENDIX E
TYPICAL TEMPERATURE CONTROL APPLICATION
FOR PMC-1 ELECTRO-PNEUMATIC CONTROLLER
The Leslie PMC-1 electro-pneumatic controller provides an
accurate, economical alternative to conventional pneumatic
or electronic controllers. A standard RTD (resistance
temperature device) is connected to the PMC-1 at the
dedicated RTD input terminals. An optional signal
conditioning card installed in the PMC-1 converts the
resistance signal from the RTD into a 4-20mA signal. The
PMC-1 compares the input from the signal conditioning card
to the set point, and, using a series of short pneumatic
pulses, modulates the control valve as required to maintain
the set point. The PMC-1’s “slow loop” control mode can be
selected for enhanced control in systems that respond slowly
to control valve changes.
During installation, the PMC-1 is calibrated by dialing in the
upper and lower limits of the signal conditioning card. The
set point and process status can then be read directly from
the backlit LCD display. The PMC-1 can be calibrated to
display the temperature in either Fahrenheit or Celsius
degrees.
14
PMC-1
Up to 100 psi
Plant air
Airset
Optional signal conditioning card installed
Drive current
Resistance Signal (Ohms)
Hot out
Trap
Cold in
Steam
RTD
