RTxxx LED lighting controllers - User Manual
7.1.1
Continuous output, switched output, selected output
Mode
Trigger input
Output
Continuous
Unused
Output is on
Switched
Trigger = off
Trigger = on
Output is off
Output is on
Selected
Trigger = off
Trigger = on
Output is continuous brightness 2
Output is continuous brightness 1
Pulsed
Trigger rising edge
Trigger falling edge
Pulse is triggered if P flag = 1
Pulse is triggered if P flag = 0
In continuous mode the output current is fixed and continuous. Switched
mode uses a trigger input to switch the output on or off.
Selected mode uses a trigger input to select between the two different
brightness settings. Brightness 1 must be greater than brightness 2. The P
flag can be used to invert the trigger input.
The output current can be varied from 0% to 100% of full brightness.
7.2
Pulsed output
The output is off by default. When the RTxx is triggered, it waits for a delay
and then pulses the output. The delay, pulse width, retrigger delay and
pulse intensity are all configurable.
Retrigger delay is the minimum allowed time from one trigger to the next.
Any triggers that happen too soon after the previous trigger are ignored.
The retrigger delay is set in multiples of 100μs.
When connected to a light, the brightness can be set up to 1000% of its
rating, but only for short periods and at low duty cycles, so that the lighting
does not overheat and get damaged. The table below shows the operating
limits:
Output brightness
Maximum
pulse width
Maximum
duty cycle
0 to 100%
999ms
100%
101% to 200%
30ms
30%
201% to 300%
10ms
20%
301% to 500%
2ms
10%
501% to 1000%
1ms
5%
The duty cycle is limited by ignoring triggers which are too soon after the
previous trigger.
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RTxxx LED lighting controllers - User Manual
For example, if the brightness is set to 250%, then the RTxxx does not
allow pulses greater than 10ms long. With 10ms pulses, if a trigger occurs
within 50ms of a previous trigger (so that the duty cycle would be greater
than 20%) the trigger is ignored.
7.3
Fault detection
The RTxxx controller detects the following errors. The error code is shown
on the webpage of an Ethernet controller (see
Section 11, Webpage
configuration (RT220, RT420, RT820F)
),or the communications window of
an RS232 controller (see
Section 12, Command configuration
). When the
output current is less than 100mA, some fault detection is disabled.
You can issue a
GR
command to cancel the error (see
Section 12,
Command configuration
). The RTxxx controller re-senses the light.
Error
Reason
34, 37
Internal power dissipation is too high. Output turned off.
35, 43
Output current to lighting is too low. The light is open cir-
cuit or there is not enough supply voltage for the reques-
ted output current.
36
If the output voltage is too low, the controller detects that
the output is short circuited.
37
The voltage required for the lighting has increased too
much. Check for ageing of the lighting or a failed LED.
38
The voltage required for the lighting has decreased too
much. Check for ageing of the lighting or a failed LED.
7.4
Light auto-sensing
When a channel does not have a light connected, the RTxxx continually
tries to supply a very small current.
When a light is connected, it flashes for a short time (the light is not
damaged by this) until the RTxxx detects that it is conected.
For voltage rated lights, the light is briefly driven at an increasing amount
until 100% output brightness is achieved in order to sense the current
rating of the light. This can generate the following errors:
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