External Switching Modem - Honeywell SDC Service Manual

Hydraulic Components
7.3.10.4
Function
Assignment
NOTE
220

External switching modem

Only activated if setting 11 (external switching modem) was
selected for parameter 08, 09 or 10 (variable inputs) in the
"Hydraulics" menu.
This configuration allows switching between control modes via the
telephone using a switching modem to be provided by the user
(for holiday homes etc.).
A switching modem can be assigned to each of the three variable
inputs (VI1 ... VI3). If a variable input is assigned this function, the
associated parameter appears in the "System" menu for
assignment of the switching modem to the respective heating
circuit. The same parameters and areas are involved here as with
the demand contact, i.e. the modem acts either on the direct
circuit (DC), mixed heating circuit 1 (MC1), mixed heating circuit 2
(MC2), hot-water circuit (HW) or the entire system (ALL), i.e.
globally on all central devices on the data bus system.
The control mode depends on the wiring at the respective variable
input in the following way:
Connection terminal of variable input 1 (2, 3) open:
Control based on the current control mode (AUTO, RED.
HEATING, HEATING, STANDBY)
Connection terminal of variable input 1 (2, 3) short-circuited:
Control functions in standby mode; heating and hot water are
switched off frost protected.
Connection terminal of variable input 1 (2, 3) with terminating
resistor with 10 kOhm
Control based on continuous heating.
Connection terminal of variable input 1 (2, 3) with terminating
resistor with 2.2 kOhm
Control based on continuously reduced operation (according to
specification as reduced or switch-off mode).
Only one modem can be connected to each control device.
SDC / DHC
EN2H-0221GE51 R0812