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(2) Dead band
Dead band refers to the temperature area where neither heating control output nor cooling control output is
performed. When the temperature process value (PV) is stable within this area, output is not performed for the
slight change in the temperature, resulting in energy saving.
When remote buffer memory values are set as follows:
Ex.
• CH Input range (address: 100H, 130H, 160H, 190H): 38 (temperature measurement range -200.0 to
400.0)
• CH Set value (SV) setting (address: 101H, 131H, 161H, 191H): 2000 (200.0)
• CH Overlap/dead band setting (address: 1C7H, 1CCH, 1D1H, 1D6H): 25 (2.5%)
200.0 to 215.0 is the area for dead band.
(Full scale) (Dead band setting) = (400.0 - (-200.0)) 0.025 = 15.0
The temperature where cooling operation starts = (Set value (SV)) + 15.0 = 215.0
As shown below, shifting the temperature where cooling operation starts to the higher temperature side of the set
value (SV) produces a dead band area. (The following is an example of when the module is in P control.)
Heating only
(manipulated value for cooling (MVc): 0%)
100%
Heating
0%
-100%
220
Manipulated value
for heating (MVh): 0%
Manipulated value
for cooling (MVc): 0%
Set value (SV): 200.0°C
Cooling only
(manipulated value for heating (MVh): 0%)
Temperature to start cooling:
215.0°C
Cooling
Temperature
process value (PV)
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Troubleshooting
