Function Description Of Power On And Reset - Siemens RVW26.000B27 Basic Documentation

Siemens Building Technologies
HVAC Products

5.5 Function description of power ON and reset

When power is switched off, readiness contact «Q4-Q5» is open and «Q4-H» closed.
Each time power is switched on, the RVW26... makes internal tests for about 2 sec-
onds.
During this period of time, the unit's display shows «88.8», both LEDs are lit, readiness
contact «Q4-Q5» remains open and «Q4-H» closed.
On successful completion of these tests, readiness contact «Q4-Q5» closes and the
display returns to normal operation.
At this point in time, the RVW26... tests the end switches of the actuators by driving
them briefly toward «Fully open» and then immediately toward «Fully closed».
Brief switching off and on of mains voltage (reset) resets the RVW26... after a lockout.
As long as the cause of the fault is not removed, the RVW26... will again go to lockout
and display the corresponding error code.
Note:
The RVW26... can be reset after a lockout by briefly switching power off.
When doing planning work, it is recommended to include a push button in the line, enabling
.
the unit to be reset
L
EK
L
RVW26
N
N
Fig. 12 Connection of lockout reset button «EK» (example)
Electronic Air / Fuel Ratio Control System
5 Description of functions
Control loop
Q4 Q5
H
Indication of fault
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CC1P7873.1en
15.10.2002