THE PC ENERGY CONTROLLER 
performs ON/OFF load control and 
ANALOG-OUT control based on its program, on DIGITAL-IN's and on ANALOG-IN's.

COMMAND SYNTHESIZER generates the outgoing PLC signal and analyzes the PLC answers from Responders and Unit Controllers. It handles DlGITAL-OUT, DIGITAL-IN, ANALOG-OUT and ANALOG-IN.

COMMAND TRANSMITTER / RECEIVER amplifies PLC signal and superimposes it onto the AC wiring of the building. It also amplifies and detects the return PLC from the Responders and Unit Controllers and passes the data stream on to the Command Synthesizer.

RESPONDERS are located at the load to be controlled and respond to commands addressed to them by actuating a relay within them. The only connection between the Responder and the Controller is via the AC wiring of the building. The various types of 1-Way and 2-Way Responders are described below.

RC RESPONDERS control 1, 2 or 4 loads via internal relays. They do not produce a PLC answer.

RV RESPONDERS control 1 load and answer via PLC indicating the status of the relay which ultimately becomes DIGITAL-IN to the controller.

RA RESPONDERS control 1 load and answer via PLC to indicate status of a switch input at Responder which ultimately becomes DIGITAL-IN to the Controller.

RTC RESPONDERS control 1 load and answer via PLC to indicate the status of a switch input at Responder which ultimately becomes a DIGITAL-IN to the Controller. RTC Responders sense RTD, thermistor, voltage or current which ultimately become an ANALOG-IN to the Controller. Some also output an analog voltage which originated as ANALOG-OUT at the Controller.

IntelliStat sub-system (detailed below) consists of a UC202 local loop Unit Controller, and controls a Heater / AC or Heat Pump. It accepts commands and reports status via PLC. It also includes the TDC2 Temperature Display/ Control Unit which contains an LCD and displays space, outdoor, and set point temperatures. Buttons allow user to change settings and control override functions.