MobileView PENTA, Installation Manual

Page: 42 / 114

Chapter 3: DVR installation
36 MobileView PENTA Installation Manual
If full-scale input is greater than 30 VDC, the input voltage must be reduced to fall
within the supported range. Voltage reduction may be accomplished using a
simple voltage divider network (see Figure 30 below).
Figure 30: Voltage divider, analog input
In Figure 30 above, a certain amount of the input voltage (Vin) is expended
across resistor R1. The remaining voltage, Vout, is routed and monitored by the
analog input. It is up to the installer to determine the proper values of R1 and R2
based on specified voltage input variables.
The value of VOUT is determined by the formula below.
Vout = (R2 * Vin) / (R1 + R2)
Since DVR analog inputs support a maximum voltage input of 30 VDC, Vout is
always 30 VDC. For most applications, R2 can be set to 10 kΩ and the value of
Vin is the full scale value of the voltage input to be measured. Solving the above
equation for variable R1 allows simple calculation of its required value.
R1 = (R2 * Vin / Vout) - R2
In the example above, to monitor a 40 VDC variable input using a DVR analog
input would require an R1 of 3.3 kΩ with an R2 of 10 kΩ.
R1 = (R2 * Vin / Vout) - R2
R1 = (10 kΩ * 40 VDC / 30 VDC) – 10 kΩ
R1 = 3.3 kΩ
Audio output
The audio outputs are two monaural halves of a stereo output. The output is 1V
RMS line level and requires amplification by an external system.