Buderus EM10 - EM10 Communication and Signals; Communication bus setup; Malfunction signal generation; External control signal (0-10 V)

Module EM10 English
Changes due to technical improvements reserved
Module EM10 • 01/2008 13
Communication bus
Connect the EMS connection (fig. 2, pos. 6) of the EM10
with a 2-core cable to the RC- (or -) connection on the
boiler (possibly parallel to the thermostat).
Caution: This connection is polarity sensitive. The total
length of the EMS bus cable may be no more than 100 m.
Malfunction signal
The malfunction signal is given when:
– a locking malfunction occurs in the boiler,
– the system pressure is too low or
– the communication with the boiler has been interrupted
for at least 5 minutes. See wiring diagram on page 47.
The EM10 generates two malfunction signals:
a) The AS 24 V connection (fig. 2, pos. 4), this is a
potential-free switching contact for low voltage signals of
up to 24 V. This malfunction signal can for example, be
evaluated by a building management system.
b) The AS 230 V connection (fig. 2, pos. 3), this can for
example operate a horn or warning light. In case of a
malfunction, there will be 230 VAC on this connection.
External control signal 0-10 V
The EM10 can be used as an interface between the boiler
and, for example, a building management system.
With the 0-10 V DC signal (fig. 2, pos. 5), the flow tempera-
ture or the power of the boiler can be controlled (fig. 3).
a) Flow temperature-based control
The EM10 transfers the 0-10 V signal to a flow
temperature-setpoint. This is a linear ratio, see table 1.
fig. 2 Connections
pos. 1: 230 V mains supply
pos. 2: 230 V connection for a 2nd module
pos. 3: Alarm output 230 V
pos. 4: Alarm output 24 V
pos. 5: Control signal 0-10 V
pos. 6: Input EMS bus
pos. 7: Output EMS bus
AS (230V)
N
L
Netz moduleNetz module
AS 24V U EMS EMS
123 1231212
1 2 3 4567
AS 24 V no malfunction malfunction
1 and 2 interrupted closed
2 and 3 closed interrupted
fig. 3 0 – 10 V diagram
Flow temperature [° C]
External control voltage (V)
Input
voltage
Flow temperature
Setpoint (boiler)
Status
Boiler
0 V - 0.5 V 0 off
0.6 V ± 15° C on
5.0 V ± 50° C on
10.0 V ± 90° C on/maximum
table 1 Flow temperature-based control