Quantum Composers LDDC 1550 - Manual (Page 25)

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get one pulse control signal for every rising (or falling) edge that the unit receives. This is the
most common mode of operation. If you are in burst mode, then the burst sequence will start. If
in pulsed mode, then the unit will begin pulsing once an external edge is received. If stop is
selected any ongoing sequence will be stopped. Start/Stop will start a sequence on the first edge
and then stop it on the next edge. Gate mode will allow the unit to operate as long as the gate
input is either high or low (depends on mode).
Thermistor Inputs
Standard resistive thermistors NTC/PTC can be monitored. The value read from these inputs (A
and B) can be queried via the USB port. Different values of thermistors can be connected to the
+ and – connections. As the thermistor resistance changes, a change in the reading will occur.
Currently an A/D bit value is returned. This corresponds to the relative change in the input
resistance. The input is measured once a query is received.
Photodiode Input
A photodiode input can be monitored. A standard photodiode can be connected to the anode and
cathode inputs. The input is configured in a photoconductive mode with a zero bias. The ouput
that is read will be proportional to the current generated by the photodiode. This value can be
queried from the USB port. Values read are in A/D counts from 0 to 1024. The input is measured
once a query is received.
Spare Analog Input
An analog input can be used to monitor a 0-5V input from various devices or sensors. This value
can be read from the USB port. Values are in volts measured from 0 to 5V. The input is
measured on a query.
Spare Analog Output
A spare 0-10V output can be independently controlled for controlling various devices such as a
TEC controller. This output can be set from 0-10V via the USB port. The output is changed once
the command is processed.
Spare Inputs
Three TTL compatible inputs can be monitored for various uses. Voltage levels from 0 to 5V can
be monitored via the USB port. Values are read and returned once the command is processed.