tekmar 162 Setpoint Control Installation - Manual (Page 6)

© 2007 D 162 - 08/07 6 of 32
Applications: Pulse Width Modulation
Mode 4 Setpoint (PWM)
Load
Mode 5 Floor
Mode 6 Pool
Heating PWM Operation
Wa
rm
er
Set Heat
Cycle Length
Heat
Relay 1
On
Relay 1
On
Relay 1
On
Setpoint
Relay 1 Pulse Width Modulation (PWM) Operation
PWM operates by centering the throttling range around
the target setpoint temperature. PWM is best suited for
large heating or cooling loads that do not change rapidly
in temperature. The Differential setting in the ADJUST
menu changes the throttling range while in Application
Mode 4 (Setpoint). The throttling range is not adjustable
in Application Modes 5 (Floor) or 6 (Pool).
Heating Operation
When the temperature is at the setpoint, Relay 1 is on
for 50% of a cycle and off for 50% of a cycle. When the
temperature is 1/2 of the throttling range below the setpoint,
Relay 1 is on for 100% of a cycle. When the temperature is
1/2 of the throttling range above the setpoint, Relay 1 is off
for 100% of a cycle. For ranges within the throttling range,
Relay 1’s on time increases linearly as temperature falls.
Cooling Operation
When the temperature is at the setpoint, Relay 1 is on
for 50% of a cycle and off for 50% of a cycle. When
the temperature is 1/2 of the throttling range below the
setpoint, Relay 1 is off for 100% of a cycle. When the
temperature is 1/2 of the throttling range above the
setpoint, Relay 1 is on for 100% of a cycle. For ranges
within the throttling range, Relay 1’s on time increases
linearly as temperature rises.
Cooling PWM Operation
Cooler
Set Heat
Cycle Length
Cool
Relay 1
On
Relay 1
On
Relay 1
On
Setpoint