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Monitoring system MRB – Control unit RCMU8
Operating indicators
34 LEDs are used to present the control unit’s operating
status with, among other features, individual indicators for
each damper and function as follows:
OPERATION is indicated by a green LED as follows:
- Lit during normal operation when the RCMU is
functioning independently and is not connected to
a network
- Lit 2 s/off 0.5 s during normal operation when the RCMU
is connected to a network
- Lit 0.1 s/off 0.1 s in case of network fault
- Off in case of power failure
OPERATION VENT. - Green LED lit when output relay for
vent. unit is activated.
NIGHT OPERATION - green LED lit in case of activated
input.
FUNC. TEST - yellow LED lit during internal function test.
- Lit 2 s/off 0.5 s during external function test
EXT. ALARM - red LED lit in case of activated alarm input.
DAMPER POSITION - indicated by green LED as follows:
- Lit in open position
- Lit 2 s/off 0.5 s in closed position
- Lit 0.1 s/off 0.1 s in middle position
- Off when damper motor is not connected/overloaded
DAMPER FAULT - indicated by red LED.
Function when LED for DAMPER POSITION is lit with
indicator as above:
- Lit when damper will not open
- Lit 2 s/off 0.5 s when damper will not close
- Lit 0.1 s/off 0.1 s when damper will neither open nor
close
- Lit 0.5 s/off 2 s when damper indicates open and
closed simultaneously
Function when the LED for DAMPER POSITION is off:
- Lit 0.1 s/off 0.1 s in case of overload on one of outputs
(both damper fault LEDs flash).
- Lit 2 s/off 0.5 s in case of motor failure
DETECTORS FAULT - red LED lit for each detector loop
in case of break in detector loop.
- Lit 0.1 s/off 0.1 s for each detector loop in case of
short circuit in detector loop.
DETECTORS ALARM - red LED lit for each detector loop
in case of triggered detector.
DETECTORS SERVICE - yellow LED lit for each detector
loop in case of dirty detector.
Resetting
The RESET button resets all alarms. After activation the
microprocessor performs a self-test, a memory test and an
EEPROM test, all LEDs are lit for a visual test, output relays
are activated and then dampers connected to groups A+B
and then groups C+D are function tested. After the test the
RCMU8 enters normal operation mode.
External incoming alarms can be reset remotely by activat-
ing the “External Function Test” input. Other alarms cannot
be reset remotely. Not used with network connection.
Night operation
Via an external switch the panel enters NIGHT OPERA-
TION mode, at which time the dampers close without the
control unit triggering an alarm.
The external switch must be controlled by a time channel
from DUC, a timer or similar device and not from the venti-
lation unit to avoid “self-locking”. Used, for example, during
intermittent operation. Not used with network connection.
Controlling the ventilation unit
If you want to stop the ventilation unit in conjunction with
a function test or in case of alarm operation, there is an
integrated closing relay switch, 24 V AC, 3 A.
A microswitch marked “Delay” can be used to activate
a 5-minute delay on the dampers’ function test if using
an electrically-heated thermobattery. The relay remains
activated throughout night operation. Damper faults do not
affect the above functions.
Network connection
When the RCMU is connected in a network to a minimas-
ter RCMM, the RCMM determines which functions the
RCMU is to perform. In the case of a network fault during
operation the RCMU will enter alarm mode and the main
alarm will be triggered.
Use RCMU8-MOD to connect to a Modbus network. The
network can have free topology and the following informa-
tion can be transferred:
• Status of RCMU8-MOD
• Which outputs have connected dampers
• Damper faults with detailed causes
• Detector faults and detector alarms
• Service alarms
Furthermore, the following options are available for con-
trolling RCMU8-MOD Modbus-based equipment:
Remote reset | Function test | External alarm | Night
operation
