CMA Dishmachines DIFFERENTIALVOLTAGE SENSOR 0210I User manual

DIFFERENTIAL
VOLTAGE SENSOR 0210I
-10 .. +10 V
User’s Guide
Figure 1. The Differential Voltage sensor -10 .. +10 V
CENTRE FOR MICROCOMPUTER APPLICATIONS
http://www.cma-science.nl

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Description
The Differential Voltage sensor 0210i is designed for exploring the basic principles
of electricity. With a wide input voltage range of 10 V this sensor can be used to
measure voltages in AC and DC circuits.
The sensor has differential inputs, which means that measurements can be done
directly across circuit elements without the constraints of common grounding. It can
be used to measure positive potentials, as well as negative potentials. It has two
banana (4-mm) plugs for easy connection.
The Differential Voltage Sensor should be connected parallel to a circuit element. It
measures the potential difference between the V+- red plug and the V-_- black plug.
The measured voltage goes through an amplifier unit and the output of the sensor is
adjusted to the range of 7V, which can be measured by an interface.
The sensor is provided with over-voltage protection and voltages up to 50V
(related to ground) will not damage the sensor. It never can be used for higher
voltages or 220V.
The sensor is excellent to sample AC-signals at relative high frequencies (< 100
kHz).
The sensor is equipped with a BT plug and can be connected to the following CMA
interfaces: €Lab, CoachLab II/II+and ULAB. Furthermore the sensor can be used
with Texas Instruments CBL, CBL2and Vernier LabPro.
Sensor specifications
The Differential Voltage sensor has a memory chip (EEPROM) with information
about the sensor. Through a simple protocol (I2C) the sensor transfers its data: name,
quantity, unit and calibration to the interface1.
Examples of experiments
The Differential Voltage sensor can be used in various experiments such as:
charging and discharging capacitors,
characteristics of a light bulb and a diode,
measurements of internal resonance and EMF,
measurements in series and parallel electrical circuits.
Together with a Current Sensor it can be used to explore the relationship between
the current and the voltage in electrical circuits - the Ohm’s Law.
1This is valid for the following interfaces: CMA €Lab, BT inputs of CoachLab II/II+and ULAB,
TI CBLand CBL2, and Vernier LabPro.

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Calibration
The output of the Differential Voltage sensor is linear with respect to the input
voltage. To collect data you can:
1. Use the calibration supplied by the sensor EEPROM memory.
2. Use the calibration supplied in the standard sensor library of the Coach program.
3. Calibrate the sensor using known voltages (a standard, simple 2-point calibration
can be done). User calibration can be performed in the Coach software.
The name of the Differential Voltage sensor in the sensor library of the Coach
program is Voltage sensor (differential) (0210i) (CMA) (-10 ..10 V).
Figure 2.
Default calibration graph of the
Differential Voltage Sensor (used in the
Coach sensor library and in the sensor
memory).
Vin (V)= 1.616 * Vout (V) - 0.0081
where Vin = V+- V-
Default linear calibration coefficients:
a=1.616; b=-0.0081

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Technical data
Differential input voltage range
Common-mode input voltage range
± 10 V (voltage between input terminals)
± 50 V (voltage related to ground)
Output voltage range ± 7V
Gain 0.619 x
Resolution using 12 bits A/D converter 7.9 mV
Calibration function Vin (V) = 1.616 * Vout (V) – 0.0081
where Vin = V+- V-
Input impedance to ground each terminal 1 M
Input offset voltage error typical ± 8 mV
Common-mode input voltage error typical 0.03 mV/V (0 – 500 Hz)
Non-linearity < 0.001 %
Slew rate 10 V/s (maximum output voltage variation)
Bandwidth (small signal) 1.2 MHz (-3dB)
Supply voltage
Supply current
5 V DC
typical 19 mA
Maximum differential input voltage
Maximum common-mode input voltage
± 50 V (max. voltage between input terminals)
± 50 V (max. voltage related to ground)
Sensor information for
Auto-ID and calibration 256 byte serial EEPROM
Connection Right-hand BT (British Telecom) connector
Warranty:
The 0210i Differential Voltage sensor is warranted to be free from defects in
materials and workmanship for a period of 12 months from the date of purchase
provided that it has been used under normal laboratory conditions. This warranty
does not apply if the sensor has been damaged by accident or misuse.
Note: This product is to be used for educational purposes only. It is not appropriate
for industrial, medical, research, or commercial applications.
Rev. 1/11/12