Controller Operation - Logix TC-2000 Operation And Installation Manual

Stage 1 and 2 LEDs - used to indicate the on/off state of each output relay during normal operation. During configuration, the
LEDs indicate which stage is being configured.
Remote LED - used to indicate the TC-2000 is integrated, monitored and controlled remotely by a Logix® Industrial Control
System.
Network LED - used to indicate network communications activity between the TC-2000 controller and a Logix® Industrial Control
System or a standard PC (requires optional TankView™ PC software).

Controller Operation

Activating and De-activating the Controller - pressing the On/Off button will toggle between the Automatic and Standby modes
of operation. The On/Off button has a short delay built into it and must be held briefly to toggle the mode - this prevents
inadvertent mode changes. If power is removed and then reapplied to the controller, it will return to the operating mode it
was in prior to the power removal.
Viewing the Current Setpoint - while the controller is in the normal operating mode (not configuration), pressing the
button will cause the stage 1 setpoint to be displayed as well as lighting the Stage 1 LED. Pressing the
cause the stage 2 setpoint to be displayed as well as lighting the Stage 2 LED. When the button is released, the display will revert
back to the current temperature.
Stage 1 and Stage 2 Operation Stage 1 and Stage 2 can be independently set for either cooling or heating mode (see
configuration, below). Each stage has both a temperature control setpoint as well as a control deadband. The control deadband
prevents excessive output relay cycling by creating a "dead" control zone centered around the control setpoint. No control change
occurs while the temperature is inside of the control deadband. A typical mechanical thermostat has a 5 F deadband while the
TC-2000 deadband can be adjusted anywhere between 0 and 50 F.
Cooling Mode Diagram
Heating Mode Diagram
During normal operation, whenever a Stage 1 or Stage 2 output relay is energized the respective Stage 1 or Stage 2 LED will be
illuminated.
High and Low Temperature Alarm - The high and low alarm functions provide a visual warning. The temperature display will
flash on/off if the process temperature exceeds the High Temperature Alarm setpoint or falls below the Low Temperature Alarm
setpoint. The flashing alarm indication will automatically reset when the process temperature returns to normal. Stage 2 can also
be configured as an alarm output (see Controller Configuration). When configured as an alarm, any alarm condition will energize
the stage 2 control relay output. The alarm output can be "silenced" or de-energized by pressing either the up or down key.
Differential Control - The TC-2000 dual sensor controller can be configured to control Stage 2 based on the difference
(differential) between sensor one and sensor two. To enable differential control, set the Stage 2 Mode setting to dIF and set the
Stage 2 Control Setpoint to the difference between sensor measurements (specifically, Sensor 2 minus Sensor 1). For example,
if the Stage 2 Control Setpoint is set at 5 F, the Stage 2 Deadband is set at 4 F and Sensor 1 measures 50 F, the Stage 2
Cooling Mode - in the cooling mode, the relay output will de-energize when the process temperature
falls below the temperature setpoint less one half of the deadband setpoint. Once the process
temperature rises above the temperature setpoint plus one half of the deadband setpoint the output
relay will energize.
Heating Mode - in the heating mode, the relay output will energize when the process temperature
falls below the temperature setpoint less one half of the deadband setpoint. Once the process
temperature rises above the temperature setpoint plus one half of the deadband setpoint the output
relay will de-energize.
Logix® TC-2000 Process Controller, Page 2 of 7
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