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Building Technologies
Boiler sequence controller RMK770
CE1P3132en
HVAC Products
3 Commissioning
23.04.2009
3.3.2
Terminal assignment and properties of outputs
In principle, all input and output terminals can be freely used. The terminals preas-
signed when selecting the plant type can also be reconfigured. In that case, however,
the special properties of the individual extension modules, and their outputs, must be
taken into consideration.
When controlling a shutoff valve, an on/off signal is usually required. For that purpose,
a number of relays with changeover contacts are available.
In the case of the RMK770 and RMZ789, these are outputs Q1 and Q4; in the case of
the RMZ787 and RMZ788, output Q5.
The relay outputs for the on/off signal of 3-position control are assigned as pairs. The
available terminals are the terminal pairs Q1/Q2, Q3/Q4 and Q5/Q6. Usually, special
terminal pairs must be used.
Normally, for 3-position control of a mixing valve or modulating burner with on/off signal,
appropriate radio interference suppression measures must be taken. If the mixing valve
does not already incorporate such RC units, appropriate devices must be provided
either on the controller side or externally.
With the RMZ789 extension module, there are 4 mixing valve outputs available, where
an RC unit can be easily activated.
Q11
Q14
Q12
C
R
Q24
N1
N
L
R
N2
Q22
L
C
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32
Z
03
RMZ789
Q1 N1 N2 Q2 Q3
Q4
N3 N4
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Z0
4
When terminals N1 and N2 or N3 and N4 of the extension module are interconnected
and wired to N, the RC unit for outputs Q1/Q2 or Q3/Q4 is activated.
RMK770
Q1 N1 N2 Q2 Q3
Q6
Q4 Q5
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3
2Z0
5
Q7
( )( )
On the RMK770 basic unit, terminals Q1/Q2 can also be used for activating an RC unit.
Outputs Q3/Q4 and Q5/Q6 can be configured as 3-position outputs but are not
equipped with RC units.
RMZ787
Q1 Q2 Q3
Q5
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32
Z0
6
( )
RMZ788
Q1
Q5
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Z0
7
With the extension modules RMZ787 and RMZ788, it is only output pair Q1/Q2 that can
be used as a 3-position output, but this output is not equipped with RC units.
Outputs with
changeover contacts
Terminals for
3-position control
Outputs with RC units