Rev. d 01/1 11
DMP052E
MIN/MAX HUMIDITY LIMITS ON A1 AND D1 LOOPS
Limit loops are optionally active in A1 and D1 loops only; they are P-type and always operate with
fixed set-point. If enabled, they work in parallel to the control loop. For each operating mode
(except Mode D4) both minimum and maximum limits can be enabled separately.
For each control loop different settings are
available:
- Limits disabled
- Active minimum limit for heating
- Active maximum limit for cooling
The behaviour of a limit loop output will be
different if the loop is in heating or cooling
mode.
For A3, A4 and D3 operating modes, it is
possible to enable the minimum limit for
heating and/or the maximum limit for
cooling.
The term “minimum humidity limit” indicates
a function intended to avoid that the
humidity detected by the
SH
limit sensor
drops under given values.
The term “maximum humidity limit” indicates
a function intended to avoid that the
humidity detected by the
SH
limit sensor
exceeds given values.
In a
HEATING LOOP:
If the
Minimum Humidity limit
function is
enabled, it uses the output
maximum value
among the limit Loop and Control Loop. A greater heat supply allows a better operation of the
humidification device, avoiding the risk of condensation and improving the plant efficiency.
If the
Minimum limit is enabled, it is necessary to define:
- MINIMUM LIMIT SET POINT
- MINIMUM LIMIT PROPORTIONAL BAND
In a
COOLING LOOP:
If the
Maximum Humidity limit
function is enabled, it uses the output
maximum value
among the
limit Loop and Control Loop. A higher cooling in the air duct allows reducing the humidity supplied
to the environment. If the Maximum limit is enabled it is necessary to define:
- MAXIMUM LIMIT SET POINT
- MAXIMUM LIMIT PROPORTIONAL BAND
It is not possible to enable the Limit function in operating mode D4. The Limit Loop set point
operates at fixed point and is not modified neither in
Reduced
mode. The Limit Loops are disabled
under
Stop
Operating Mode. The Limit sensor used by the loops A1 and D1 is the one connected
to the
SH
Humidity sensor input, if not differently specified (“SH sharing” see paragraph related to
LinkBus). If the Limit is enabled on any Operating Mode and the Limit Sensor is not connected
correctly to
SH
terminal or is not shared correctly with other devices, the Anomaly Led
@
switches
on, the control loops A1 and/or D1 are stopped and the relevant Ao1/Rel1 output switched off.
For all limit parameters settings see page 18.
