Ocean Optics NeoFox - Manual (Page 68)

C : Analog Output
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Analog Current Boundaries
The analog current lower bound represents the value of the data source that corresponds to a 4 mA analog
output. The analog current upper bound represents the value of the data source that corresponds to a 20
mA analog current output. Intermediate values are linearly scaled across this region to produce the
appropriate output. Values of the data source that fall outside this region result in output currents that are
either 4mA or 20 mA depending on whether the value of the data source exceeds the upper bound
(resulting in 20 mA) or falls short of the lower bound (resulting in 4 mA).
Analog Data Range Example
As an example, consider the following. A user who is interested in using the analog voltage output to
monitor oxygen in the range from 4.5 ppm to 7 ppm would select the following settings. The result would
be that any ppm values below 4.5 ppm would result in an output of 0 volts and any values above 7 ppm
would result in 5 volts. In this case, 6.3 ppm would produce an analog voltage output of [(6.3 - 4.5) / (7 -
4.5)] * 5 = 3.6 volts.
 Analog Voltage Source: 5 – Alternate O2 Units
 Analog Voltage Lower Bound: 4.5
 Analog Voltage Upper Bound: 7.00
 (Oxygen Units) – “DO – ppm – Water”. (Selection of ppm as alternate O2 units)
Saving the Analog Output Settings
To save the analog output settings, open the “Advanced Settings” control panel and then select “Enabled”
from the dropdown box located to the right of the “Flash Write” setting. This box will momentarily
continue to display “enabled”, but will switch back to “disabled” when the unit has processed the
command.
Analog Output Pinouts
Caution
Be careful when wiring. Incorrect wiring could cause permanent damage to the unit.
View of Connector on Back of NeoFox Unit
1 = RS232 Rx
2 = 0-5V – V+
3 = Current 4-20 - V- (Iout)
4 = Current 4-20 - V+
5 = RS232 Tx
6 = 0-5V / RS232 GND
This is the view looking at the connector on the back of the NeoFox, with power plug on the right
and the USB plug on the left. The connector is a standard PS-2 connector.