Pico DrDAQ® USB data logger, oscilloscope attachment, data logger, signal generator PP706 PP706 Manual Do Utilizador
Códigos do produto
PP706
Product information
32
Copyright © 2011 Pico Technology Ltd. All rights reserved.
usbdrdaq.en
Some simple scaling examples:
Example 1: Interfacing a Resistive sensor
Notes:
Light-dependent resistor (LDR) can be
used in conjunction with a fixed
resistor to measure light level. A
suitable LDR sensor can be obtained
from Maplin Electronics (part number
N53AY). A resistor (R) of around 500k
is suitable.
used in conjunction with a fixed
resistor to measure light level. A
suitable LDR sensor can be obtained
from Maplin Electronics (part number
N53AY). A resistor (R) of around 500k
is suitable.
Example 2: Measuring 4-20 mA Current
Notes:
4-20 mA output is the industry
standard for interfacing between a
control centre (data logger) and a
remote process such as a sensor. For
this reason 4-20 mA sensors are very
common.
standard for interfacing between a
control centre (data logger) and a
remote process such as a sensor. For
this reason 4-20 mA sensors are very
common.
For relatively small currents a simple
shunt resistor can be used to convert
the current into voltage which the
DrDAQ can then measure.
shunt resistor can be used to convert
the current into voltage which the
DrDAQ can then measure.
A suitable resistor (R) for the USB
DrDAQ is 120 ohms. This would give
(using Ohm's Law):
DrDAQ is 120 ohms. This would give
(using Ohm's Law):
0.4 volts at 4 mA
2.4 volts at 20 mA
2.4 volts at 20 mA
P = VxI
Therefore >50 mW resistor required.