Error! No text of specified style in document. DNS-24, DNT-T103, & DNT-T221 Application Guide
Page 28 of 35
Document Edition 3.1
3. TIME PROPORTIONED (TP)
The DNT-T103 can have up to two stages of Time Proportioned heat (Outputs 2 and 3), while the DNT-T221 can
have one stage (Output 3). These are similar to the PWM outputs except:
• The cycle time is fixed at ten seconds
• At a controller value of 0% the outputs are always O
FF
• At a controller value of 100% the outputs are always O
N
• The controller value, from 0 to 100%, is mapped into the duty cycle directly (i.e., 50% is 5 seconds O
N
and 5 seconds O
FF, for a single output).
Heating Controller Limiting
Setup variable AV29 is used as a heating controller limit. A value of 0 to 100% entered into this variable will
limit the main heating controller accordingly, and by default is set to 100%.
By limiting the controller value itself you are able to limit the output staging, which may be used for load limiting
purposes. Please note, however, that this limit is only applicable for heating, not cooling applications.
4. T
RI-STATE OR FLOATING POINT (DNT-T103 ONLY)
Tri-State uses a pair of outputs (always Outputs 1 and 2). Output 1 opens the device, and Output 2 closes the
device. It is assumed that when neither output is on the device does not change position. The Tri-State device
has a runtime property, the time that it takes to go from fully open to fully closed. It is assumed that the device
will take as long to close as it does to open and that the open and close rate is linear.
At start up the Tri-State algorithm establishes a closed position reference by closing continuously for 1.25 x the
Run Time. It will also enter this state each time that it first receives a zero position valve. A signal of 100% will
cause the algorithm to open the device for 1.25 run times to establish an open reference.
10 Seconds
Off
On
20%
2 seconds 8 Seconds
Time Proportioned
input
0%
100%
When the Input = 0%, the Output is Off all the time
Cycle time is fixed at 10 seconds
When the Input = 100%, the Output is On all the time
Output Staging is limited by the Setup 6 variable (AV29)
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