In applications where higher voltages than the
ROI-USB5 A-D
can read need to be monitored, the ROI-ISOV10 can be used to couple a
voltage divider; using an isolation amplifier, to monitor high voltage with
the 5V voltage A-D.
The voltage divider can consist of 2 resistors, with values that
represent the fraction of the applied voltage, the divider needs to produce.
In general the calculation that the divider follows, is;
Rt = Vin/Imax
where Imax is the maximum
desired current into the divider (not the maximum available, e.g.:
1mA).
Rt = (R1 + R2)
knowing that; the choice of R1 &
R2 is dependent on commercially available values, or the use of
potentiometers (keeping the input voltage a little below the A-D max can
give more options).
Vout = (Vin X R1)/(R1 + R2)
Vout is actually the voltage
fed into the measuring system.
An example of an application where this could be used is a 24Vdc level
monitor. The use of sensor transmitters in a monitoring system, depends on
having a power source that meets minimum requirements. While sensor
transmitters have a wide acceptable voltage range, the internal A-D shunt
resistor only has the remaining voltage of the supply after subtracting the
transmitter and line voltage drop.
Where could this be helpful? If the
supply powering a transmitter network developed a problem and produced
lower voltage than the design level; it is possible that the transmitter
output could be artificially low, if the measurement was at the upper end
with an incorrect supply voltage. This measurement could be used to alert
an operator to the situation before it became a problem.
The ROI-XMA
is an improved way to read sensors. Multiple sensor types. Multiple signal
ranges. High linearity. High precision. Fast response. Long transmission
distances. True analog signal conditioning, not microprocessor based A-D
conversion.
The ROI-USB combined with the
ROI-ISOV
is an improved
way to isolate your reading of high voltage. Input to output (2-way) 1.5Kv
isolation. Fast response.
True analog signal conditioning.
