Velleman projects VMBDMI Extended user manual - Manual (Page 16)

16 VMBDMI Dimmer manual – edition 1
PROBLEM SOLVING
The dimmer has an indication LED. This LED indicates a fault condition by a number of light flashes.
Communication error
The LED flashes 2 times briefly.
 Check the bus-wiring for interruptions and reversing of the ‘L’ and ‘H’ terminals.
 Check the number of terminators (TERM) in the installation. Too many or not enough can cause problems.
Switch off the Velbus power supply and measure the resistance between the ‘L’ and ‘H’ terminals of the bus.
A value less than 50Ω means too many terminators, more than 250Ω means no terminators present.
 At least two modules must be connected to the bus.
Non-dimmable load
The LED flashes 3 times briefly.
The dimmer protects itself from to inductive loads e.g. like in the case of a transformer without a lamp connected.
This error will disappear automatically when a lamp is connected to the transformer and the dimmer is operated
again.
For some loads e.g. dimmable LD lamps it is better to disable this control via the configuration software
(Velbuslink). Set the dimmer for resistive loads.
Temperature alarm
The LED flashes 4 times briefly.
The dimmer has a temperature sensor built-in. When the internal temperature is too high (>80°C) the dimmer will
auto-protect itself by reducing the dimming value to 25% of the desired value. When the temperature drops below
60°C the fault will reset itself automatically.
Check following points:
 Connected power too high
 Not enough free space around the dimmer (leave at least 1 module free)
 Temperature inside distribution box too high (provide ventilation inside distribution box)
Output LED
 Two short flashes: communication
error
 Three short flashes: non-dimmable
load
 Four short flashes: temperature
alarm
 Five short flashes: thermal
protection