Output; Output 4; Output, Modulating; Output, Multistage - Siemens LMV51 Series Basic Documentation

Output, modulating

Output, multistage

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6.9 Output

6.9.1 Output 4...20 mA
This active output serves primarily for covering the current load, e.g. for boiler se-
quence control and for display by the BACS (if no bus interface is used).
If a voltage signal is required, it can be delivered by connecting a resistor (maximum
500 Ohm).
Burner OFF
I (mA) 4
Burner OFF
I (mA) 4
Tolerance ±5 %

6.10 Multiboiler plants

Boiler sequence control is accomplished with the help of external devices or control
systems (e.g. BACS or PCs).
In principle, there are 2 choices available:

6.10.1 Multiboiler plants by means of an analog input

For that purpose, the LC of the LMV5... has an analog input (X62).
This means that the individual boilers can be
a) released / locked, and
b) operated at the required output
(or set to the required setpoint)

6.10.2 Multiboiler plants by means of a digital interface

For that purpose, BACS terminal X72 on the AZL5... can be used with the help of the
bus interface.
Inputs:
Controller release / lock
−
Predefined setpoint or predefined load
−
Outputs:
Actual value
−
Controller ON / OFF
−
Manipulated variable multistage / modulating
−
Error messages
−
For more detailed information, refer to → section 7.2.2 Connection to superposed sys-
tems.
Basic Documentation LMV5...
6 Temperature or pressure controller (internal load controller LC)
0 % 100 %
4
Stage 1 Stage 2
5 10
20
Stage 3
15
CC1P7550en
13.08.2004