Notes
[1] Output intensity can be set from 0–100%; however operation in the range 0–5% is not
recommended.#
[2] Setting the intensity slider to zero is not functionally equivalent to turning light output off using
the ON-OFF button. In this condition, the fan will continue to run as the light sources are still
energized, even though their output may not be detectable.#
3.5 TTL Interface
The TTL interface provides users with a faster method of switching color channel outputs on and off.
Individual TTL lines are provided for each color channel (see TTL Connector Pin Definitions table).
These can be conveniently addressed using an accessory BNC breakout cable (Lumencor part
number 29-10015 or 29-10080) connected to the rear panel DB15 TTL port. Note that TTL and serial
on/off commands have a logical OR relationship. Therefore source on/off controls on the light
engine control pod, in the SPECTRA GUI or in third-party image acquisition control software must be
set in the “OFF” state when using TTL control. The TTL interface does not control source output
intensity, which remains under serial (RS-232) control. TTL polarity (ACTIVE = HIGH or ACTIVE =
LOW) is factory set according to order specifications.#
3.6 Metered Dosage Operation
Open loop and closed loop output monitoring and feedback systems are available as optional add-
ons for SPECTRA and SPECTRA X light engines. These systems consist of a modified output
adapter that directs a small fraction of the light output to an onboard reference photodiode, together
with supporting signal processing electronics. For open loop monitoring , the reference signal is
output to a rear panel BNC connector (Figure 7) for external display or processing. In closed loop
operation, activation of the selected light source starts an onboard counter that accumulates the
active reference count from the photodiode and compares it to a control count value input by the
user. When the reference count reaches the control value (i.e. when the metered light dose has been
delivered), the light output automatically shuts off. All closed loop metered dosage functions are
controlled from a serially connected computer. A Windows GUI implementation is available free on
request. The GUI also includes standard SPECTRA source selection and intensity setting controls
(Section 3.4). Further details of metered dosage operation are available on request.#
To Next Page
Loading...
