User manual

SEC-HD user manual Programming the parameters
33
Proportional cooling
When configured for proportional cooling, the relay controls a water pump or sprinkler solenoid
and operates as a proportional cycle timer. The relay switches on for a portion of the cycle/interval
and off for the remainder. The duration the relay is on depends on the temperature. Proportional
cooling allows you to control temperatures more effectively and efficiently.
Typical use for proportional cooling is soaking or direct evaporative cooling, which is often used in
hog and dairy operations.
The following example uses the default settings for Program A.
 Parameter 12, Stage 5 set point = 84.0°F
 Parameter 13, Stage 5 P-band temperature = 2.0°F
 Parameter 14, Stage 5 P-band interval = 10 minutes
10 minutes ÷ 2.0 = 5 minutes change per degree, therefore:
 At 84.0: 0.5 min on (this is the minimum time regardless of interval parameter), 9.5 min off
 At 84.5: 2.5 min on, 7.5 min off
 At 85.0: 5 min on, 5 min off
 At 85.5: 7.5 min on, 2.5 min off
 At 86.0: 10 min on, 0 min off (always on)
When the temperature is below the set point (12) the water pump is off.
The minimum relay ON duration is 0.5 minutes.
When the temperature is above the set point (12), plus the proportional
band setting (13), the water pump is always on.
When the temperature is between the set point (12) and the proportional
band temperature, the water pump is on for a duration, and then off for a
duration.
84.0°F
86.0°F
Temperature