QPRO Technical Data Sheet
Document 1137-0901, REV A
13
Figure 4-2, Sample 12V Sensor
24V
(SENSOR)
21K, 10mW
3.57K, 10mW
ANA 0 OR ANA 1
R1
3.5V
R2
Figure 4-3, Sample 24V Sensor
The equation below can be used to determine the appropriate resistor value for sensors that are current
scaled
.
=
mA
F
s
Full Scale Milliamp Reading
mA
F
V
R
s
5
.
3
=
The example below will scale a 0-20mA sensor to 0-3.5 VDC at the input to the modem
.
Figure 4-4, Sample 24V Sensor
4.2
Digital Inputs/Outputs
Eight general purpose digital inputs/outputs are available: Pins 27 thru 34
•
TTL/CMOS (3.5VDC) levels
•
Configurable as inputs or outputs
•
No internal pull-up or pull-down resistor
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