13

TEMPERATURE

COOL

HEAT

SETPOINT

-100%

O2

+100%

O1

2X PROPORTIONAL

BAND

%

OUTPUT

POWER

O1

+100%

SETPOINT

DEADBAND

NEGATIVE VALUE

COOL

RELATIVE GAIN = .5

.5

1

2

RELATIVE GAIN

O2

-100%

TEMPERATURE

HEAT

%

OUTPUT

POWER

TEMPERATURE

HEAT

SETPOINT

-100%

O2

+100%

O1

DEADBAND

POSITIVE VALUE

RELATIVE GAIN

21

.5

RELATIVE GAIN = .5

COOL

%

OUTPUT

POWER

HEAT/COOL RELATIVE GAIN FIGURES

Heat/Cool Deadband = 0

Heat/Cool Deadband < 0

Heat/Cool Deadband > 0

STEP 14 PROGRAMMING THE COOLING

To enable Cooling in Heat/Cool applications, the Alarm 2 Action must first be set for Cooling. When

set to cooling, the output no longer operates as an alarm but operates as an independent cooling output.

The OP2 terminals are the same as AL2. Cooling output power ranges from -100% (full cooling) to 0%

(no cooling, unless a heat/cool deadband overlap is used). The Power Limits in the Output category also

limits the cooling power.

Cycle Time (40141/40241): This cycle time functions like the OP1 Output Cycle Time but allows

independent cycle time for cooling. A setting of zero will keep output OP2 off. The status of OP2 can

be read through registers (40016/40032).

Relative Gain (40142/40242): This defines the gain of the cooling relative to the heating. It is generally

set to balance the effects of cooling to that of heating. This is illustrated in the Heat/Cool Relative Gain

Figures. A value of 0.0 places the cooling output into On/Off Control. This may be done independent

of the OP1 Output PID or On/Off Control Modes.

Deadband (40143/40243): This defines the area in which both heating and cooling are active (negative

value) or the deadband area between the bands (positive value). If a heat/cool overlap is specified, the

percent output power is the sum of the heat power (OP1) and the cool power (OP2). If Relative Gain

is zero, the cooling output operates in the On/Off Control Mode, with the Deadband value becoming

the cooling output hysteresis (positive value only). This is illustrated in the On/Off Control Mode

section. For most applications, set this parameter to 0.0 prior to starting Auto-Tune. After the

completion of Auto-Tune, this parameter may be changed.