Commissioning, Maintenance And Troubleshooting Help; Automatic Set Function - Honeywell SDC heating and district heating controller Service Manual

SDC / DHC
Safety temperature
limiter
Emergency mode
Data transmission
7.3.13
7.3.13.1
Function
Automatic call-up
EN2H-0221GE51 R0808
This function works as described under "Safety temperature
limiter check", with the following extension:
As soon as a safety temperature limiter function is detected within
the BUS system, all consumers (heating circuits) are disabled.
Configuration of cascade control occurs in the central device with
the bus address 10. If that controller becomes unavailable due to
some defect, the remaining stages continue operating in an
emergency mode. In this mode all heat generators adjust to the
same boiler setpoint temperature (parallel operation). As soon as
the cascade manager comes back into operation, cascade control
is reactivated automatically.
To enable the cascade function to process fast switching events,
the cascade data are transferred with a higher priority.
Consequently, the data transmission from any device to the
master device, and of the request values from the master to the
slave devices, takes no longer than approx. 3 seconds.

Commissioning, maintenance and troubleshooting help

Automatic set function

The central devices are equipped with a function which ignores
unused sensors and control functions. Fault messages from non-
connected sensors are not displayed.
The AUTO SET function is only active at power up. There are two
possibilities for calling up the AUTO SET function.
If the commissioning date has not yet been stored and the
corresponding system parameters for activating this function are
set to ON, connected or disconnected sensors are registered
automatically whenever the control device is switched on. Fault
messages from sensors (short-circuit interruption) are suppressed
in this period. After the commissioning date has been saved, a
change to the sensor configuration is only still possible after the
manual SET function. The AUTO SET function can be enabled at
any time again for a day (day change) using the system
parameter.
Hydraulic Components
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