Maximum economy changeover (MECH),
(cont’d)
When controlled via the heating sequence:
Possibility 2: Changeover
at an adjustable value
For that purpose, MECH
input 1 (MECH 1) must
be assigned an alalog
input. Function with
TYPE = ERC:
When the set MECHU limit value (MECHSET) is exceeded, the output of the HR
equipment (HREC) will be inverted.
When controlled via the cooling sequence:
When the set MECH limit value (MECHSET) is exceeded, the output of the HR
equipment (HREC) will no longer be inverted.
X3
OUTS
0 %
CTLOOP 1
y1 y2
HR
EC
HREC
OT > MECH limit value
OT < MECH limit value
Examples of changeover at an adjustable value:
Application examples
•
Changeover at an outside temperature >25 °C
•
Changeover at an outside enthalpy >30 kJ/kg
•
Changeover via an external enthalpy difference processor at an
enthalpy difference
≥
2 kJ/kg
66 / 174
Siemens
Universal Controllers RLU2…
CE1P3101en
Building Technologies
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29.08.2008