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Siemens Heating and D.h.w. Controller RVL481 CE1P2541en
Building Technologies 22 Function block "Multi-functional relay" 20.05.2008
22 Function block "Multi-functional relay"
The RVL481 features a multifunctional relay whose function is selected on this block.
This relay is also used for controlling an electric immersion heater for d.h.w. heating.
This means that if the parameters of the controller are set to "Electric heater for d.h.w.
only" (plant type x–5) or changeover operation, the relay cannot used for any other
functions. The settings on that block are then inactive.
22.1 Operating lines
Line Function, parameter Factory setting (range) Unit
141 Function of multifunctional relay 0 (0…7)
142 Manually ON / OFF 0 (0 / 1)
143 Outside temperature switch, switch-off value for occupancy time 5.0 (−35…+35) °C
144
Outside temperature switch, switch-off value for non-occupancy
time
–5.0 (−35…+35) °C
145 Outside temperature switch, switching differential 3 (1…20) °C
146 Selection time switch 3 (1…3)
22.2 Functions
The following eight functions can be assigned to the multi-functional relay:
Operating
line 141
Function
0 No function
1 Outside temperature switch
2 ON / OFF according to the time switch
3 Relay energized in the event of fault
4 Relay energized during occupancy time according to the heating
program (with no optimization)
5 Relay energized during occupancy time according to the heating
program (including optimizations)
6 Relay energized, if there is demand for heat
7 Manually ON / OFF
22.2.1 No function
No function is assigned to the multifunctional relay.
22.2.2 Outside temperature switch
Using the outside temperature switch, any pieces of equipment can be controlled de-
pending upon the outside temperature. This function requires an outside sensor or an
outside temperature signal that is delivered via the data bus.
2 different switch-off values can be set for both the occupancy and non-occupancy time
(operating lines 143 and 144). The switch-on point lies below the switch-off point, the
difference being the set switching differential (operating line 145). Depending on the
setting made on operating line 146, the occupancy and nonoccupancy times may be
those of
• the heating program (setting “0”)
• switching program 2 (setting “1”)
• switching program 3 (setting “2”)
With plant types that do not have their own heating circuit (4–x, 5–x, and 6–x), the
setting "Occupancy or non-occupancy time according to the heating program" makes
no sense, since these types of plant have no heating program. In that case, the multi-
functional relay is always de-energized.
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