Arroyo Instruments ComboSource 6300 Series, Руководство пользователя

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Page 36 · 6300 Series ComboSource User’s Manual
measured voltages is the voltage loss in the cable. Use this formula to calculate
resistance:
AMPS
laser Output
I
V V
R Cable


Note that the current is expressed in
amps , not milliamps , so divide the set point
by 1000 before using it in this equation.
Short the Connection at the End of the Cable
A second method, which does not require a DMM and can be done with just the
ComboSource , is to short the anode and cathode wires at the end of the cable
(nearest the laser diode), drive current through the cable and note the indicated
voltage on the ComboSource . The resistance is found using a simpler version
of the formula above:
AMPS
I
Vf
R Cable

Note that the current is expressed in
amps , not milliamps . The easiest way is to
drive 1A of current. When I
AMPS
equals 1A (1000mA), the displayed voltage is
also the resistance of the cable.
To short the cable, disconnect the laser and short the anode and cathode
together as close to the end of the cable as possible. Ideally, the short should be
done by soldering the anode and cathode wires together to minimize the
resistance in the short itself.
How the Calculation Is Used
The
ComboSource continuously takes the measured current, multiplies it by the
resistance ( Cable R ), subtracts the result from the actual voltage at the output
connector, and displays this value on screen as Vf . However, there are some
limitations to how the cable loss calculation is used:
1. The value for Vf Limit is always the voltage at the connector (except
when using remote voltage sense, see above). This means that the Vf
Limit must take into account all the voltage required, including the
cable loss (i.e., the voltage displayed if the Cable R value were zero).
2. Cable R is ignored in Vf mode. This means that the set point and
measured voltage are always the voltages at the connector, and Cable
R is not used.