Mode Of Operation With A Single Device (With No Bus); Mode Of Operation In Interconnected Plants - Siemens RVL471 Basic Documentation

Variant 1 – central action
of limitation
Variant 2 – local action
of limitation
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Siemens Building Technologies
HVAC Products
When the integral reaches the value of zero, the minimum return temperature limitation
will be deactivated, in which case the critical locking signal is zero.
If minimum limitation of the return temperature is active, the display shows
Minimum limitation of the return temperature can be deactivated.
Section "25.4.7 Gain of locking signal" provides information on who the critical locking
signal is sent to and how the consumers respond to it.
The minimum limit value is to be set on operating line 101. Setting --- = (inactive)
13.3.3

Mode of operation with a single device (with no bus)

Controller 1
Boiler controller
With no possibility of minimum
return temperature limitation
13.3.4

Mode of operation in interconnected plants

LPB
Controller 1
Plant type 5-0
Setting operating
line101 = 50 °C,
return sensor connected
Critical locking signal
Controller 1
Boiler controller
(With no possibility of
minimum limitation of
the return temperature)
Return temperature signal
The zone controller with its own return temperature sensor (plant type 1–x) passes the
return temperature to the other zone controllers in the same segment, which can provide
minimum limitation of the return temperature on a local basis, depending on the settings
made. This means they generate a critical locking signal internally. For response to criti-
cal locking signals, refer to section "25.4.7 Gain of locking signal".
Basic Documentation RVL471
13 Function block "Setpoint of return temperature limitation"
Controller 2
Plant type 1-1
Operating line 101 = 50 °C
return temperature sensor
connected
Critical locking signal
Controller 2
Plant type 1-0
Setting operating line 101 = - - - , no own
return sensor connected
Controller 3
Plant type 1-1
Setting operating line 101 = - - - , no own
return sensor connected
LPB
Setting operating line 101 = 50 °C,
return sensor connected
Setting operating line 101 = 40 °C, on own
return sensor connected
Controller 2 generates a critical
locking signal which shuts the
heating circuit mixing valve and
deactivates the charging pump
Controller 2 shuts the
heating circuit mixing
valve
Controller 3 shuts the heating
circuit mixing valve and deacti-
vates the d.h.w. charging pump
Controller 2 limits the
Controller 2
return temperature
Plant type 1-0
to 50 °C min.
Controller 3 limits the
return temperature
Controller 3
to 40 °C min.
Plant type 1-0
.
CE1P2524E
23.10.2002