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7. Control for ATA systems
When the MelcoRETAIL MINI powers up it automatically starts communicating with the indoor unit.
This chapter describes the control for ATA systems.
7.1. Setpoint control
The analogue input labelled
S.P.
controls the unit’s Temperature Setpoint.
The DIP switch 2-4 determines whether the input type is voltage (0-10V) or resistance (
Ω
), see chapter 4.8 for more
details.
S.P.
Input
Temperature
Setpoint
(°C)
Voltage
(V)
Resistance
(K
Ω
)
Below
0.75
Below
0.75
Uncontrolled
0.75
–
1.25
0.75
–
1.25
17
1.25
–
1.75
1.25
–
1.75
18
1.75
–
2.50
1.75
–
2.50
19
2.50
–
3.25
2.50
–
3.25
20
3.25
–
3.75
3.25
–
3.75
21
3.75
–
4.25
3.75
–
4.25
22
4.25
–
5.00
4.25
–
5.00
23
5.00
–
5.75
5.00
–
5.75
24
5.75
–
6.25
5.75
–
6.25
25
6.25
–
6.75
6.25
–
6.75
26
6.75
–
7.50
6.75
–
7.50
27
7.50
–
8.25
7.50
–
8.25
28
8.25
–
8.75
8.25
–
8.75
29
8.75
–
10.0
8.75
–
10.0
30
Above
10
Above
10
Uncontrolled
When the MelcoRETAIL MINI powers up it will read the
S.P.
input and the temperature setpoint will be determined
based on data in the table above. A command will then be sent to the indoor unit to set this setpoint value.
If the
S.P.
input changes such that a new temperature setpoint band is entered, a command will be sent to the indoor
unit to change the setpoint accordingly. There is 0.1V / 0.1k
Ω
hysteresis applied to each band change to prevent rapid
changes to the setpoint.
When LOCK mode is enabled (see chapter 4.4) the command to set the temperature setpoint will be sent every 5
seconds. This will effectively revert any changes made via a local wall controller.
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