Weather-Compensated Setpoint For Boiler Sequencing; Heat Demand Transformer - Siemens Synco700 RMK770 Documentation Handbook

Example
132/226
Building Technologies
HVAC Products
8.2 Weather-compensated setpoint for boiler se-
quencing
There may be a need to operate the boiler sequence according to a weather-
compensated setpoint without having a heating circuit. This can be the case if, for ex-
ample, a great effort would be required to integrate existing consumer circuits into the
new system.
In this case, a virtual heating circuit can be used.
This virtual heating circuit predefines a weather-compensated flow temperature setpoint
for the boiler sequence manager, including all choices offered by function block "Heat-
ing circuit".
It is thus possible to use the time program, for example, or the digital input for change-
over of the heating circuit mode to switch between no heat requisition and weather-
compensated heat requisition.
If the digital input for the room operating mode is used, it is possible to select the oper-
ating mode employed when the contact is active.
If, with the active operating mode, Comfort mode shall apply, room operating mode
Protection must be selected for the heating circuit. This ensures that, depending on the
contact position, heat demand for the boiler sequence is switched between the
weather-compensated flow temperature setpoint for Comfort mode and Protection.
To activate the virtual heating circuit, the "Heating circuit" setting in the extra configura-
tion must be parameterized to "Active". In addition, the outside temperature is required.
This can be configured in function block "Miscellaneous". The outside temperature can
also be acquired via Konnex bus. For more detailed information, refer to subsection
13.3.2 "Outside temperature".
Main menu > Commissioning > Extra configuration > Heating circuit
Operating line
Heating circuit
T T
1
2
T
T
8.3

Heat demand transformer

The RMK770 has a heat demand transformer integrated. It receives and handles the
heat requisition signals from:
• The individual room radiator (RXB...)
• The individual room air heating coil (RXB...)
• Air handling plant (RMU...)
The heat demand transformer converts the position heat requisition signals (in %) to
heat demand signals with a flow temperature setpoint.
The following example of an air handling plant shows this.
Boiler Sequence Controller RMK770
8 Heat demand and heat requisitions
Range
Active / Inactive
TFl
T
T
Factory setting
Inactive
TO
On / Off
TOeff
CE1P3132en
01.03.2005