P15280 Sensor GuideSections

Types of sensors Specification/Calibration Thermocouple Set-up on test bench Testing functionality of sensors Troubleshooting/Tips

Types of Sensors

2: K-type thermometero Sense temperature of AC motor and DC battery

1: CR5310-600 DC Voltage Transducero Monitor DC voltage of batteries of up to 600Vdc

1: CR4511-500 AC Voltage Transducero Monitor AC voltage of motor of up to 500Vac

2: Honeywell CSLA2EL Current transducero Monitor AC current of motor and DC current of batteries of up to 500A AC/DC

Specification/Calibration

Sensor Analog/Digital Output

Senses Power Supply Needed

Output range Calibration

CR5310-600 Analog DC voltage 24V 0-5Vdc Vin=120Vout

CR4511-500 Analog AC voltage 24V 0-10Vdc Vin=50Vout

CSLA2EL Analog AC/DC current 10V Depends on supply voltage

Current=(Vout-5)/(4.3*10^-3)

K-thermocouple Analog Temperature N/A Read by program

Read by Program

Where

Vout is the voltage outputted by sensor Vin is the voltage that is monitored

Please note that Vin for AC voltage is RMS value and is equal to Vpp/(2*radical(2)).

The section below shows the pin layout and specifications for each sensor used in this project.

1. CR4511-500 (AC voltage transducer)

2. CR5310-600 (DC voltage transducer)

3. CSLA2EL (AC/DC current transducer)

Pin schematic is not available. There are three pins, (+) for positive power supply, (-) for ground and (o) for output.

Thermocouple Set-up on test bench

**Please refer to hardware section of Electrical Operation Manual for detailed information in setting up voltage and current sensor on the test bench

There are two thermocouples used in this project to monitor temperature of the motor and battery. Below are pictures of their position for test bench purpose. **Please note that for better accuracy, thermocouples with a shorter rod should be used. Also, the location of the thermocouple may vary, depending on the motor used. The motor shown in the picture is an old DC motor, for the AC motor to be used by Hot Wheelz, please check with manufacturer to see which location is most vital for temperature monitoring. The same goes for the batteries.

The pictures below show the NI DAQ (left) used for processing the analog output data from the sensors. The module shown on the right is used to connect the leads of the thermocouple. Please note that the program is currently set to process thermocouple data in ports 0 and 2 of the module. If additional thermocouples are used for future purposes, be sure to turn on acquisition from the other ports in the software code.

Testing functionality of the Sensors

The section below talks about the verification of the sensors before placing onto the test bench. For step by step procedures of the tests, please refer to P15280 Test Plan documentation. The section below talks about the results from testing sensors used in this project. Please refer to pin information mentioned in section above to correctly connect each sensor.

A. AC voltage transducer test

For the AC voltage transducer, 24Vdc is applied as the power supply between pins (5) and (6). AC voltage is applied to pins (1) and (3). Output result can be read from pins (8) and (6). The table below shows the output DC voltage from the sensor as the result of the various AC voltages applied. The sensitivity equation calibration Vin=50Vout is applied to the result to find the actual AC voltage of the system, where Vout is the voltage output by sensor and calculated Vout is the output we expect from the sensor for the input voltage applied. For additional clarification, Vpp refers to the value from AC power supply. To convert it to Vin, use the formula Vin = Vpp/(2*radical(2)). As can be seen, the sensor is more accurate as higher voltages are applied.

(Please note that this is only application for when an AC motor is used, otherwise, use setup/calibration from the DC voltage transducer).

DC voltage transducer test

For the DC voltage transducer, the setup is identical to AC voltage transducer. The sensitivity equation is Vin=120Vout. Like the AC voltage transducer, the readings are more accurate as higher voltages are applied.

B. Current Sensor test

The photo above contains the setup for testing the current transducers. 8 Vdc is supplied to power the sensor (Test bench will use Vdd as 10Vdc) through (+) and (-) pin. Different input voltages are applied and connected to the 10W resistor (to generate different currents) and through the current sensor. The current received by the sensor is amplified by the amount of loops (N). In this case there are 20 loops. The output is hooked up to a multimeter through the (o) pin and reads as Vdd/2+4.3mV*N*current. Referring to the results table below, the error ranged from 0-10%.

Please note that the test uses 20 loops since the sensor senses up to 500A and has trouble measuring low amperage. Also, a 10W resistor is used since Power = Voltage * Current and normal 0.5W resistors from EE labs will easily burn up.

C. Thermocouple test

The picture below contains the setup for testing thermocouples. Two thermocouples are hooked up to the data acquisition modules. The cooking thermometer shown is used to verify the output. Ice is applied to the bowl of water until the temperature reached ~0 degrees Celsius. The temperature is captured at 5 different points and can be seen in the table above, the error ranges from 0 to 1.4 degrees Celsius between the two thermocouple outputs and the cooking thermometer.

Troubleshooting/Additional Tips

Current Transducer Pins are very fragile, as they are exposed and are connecting directly to the circuit board. Take extra care when connecting/disconnecting connectors around pins and try to limit possible sources of vibration to the pins during testing.

K-type thermocouples used in this project are connected to a long metal rod which senses temperature. For more accurate measurements, source a shorter rod so that the sense area is smaller and more precise.

Voltage transducers used in this project have warranty from manufacturer until September 2016. This warranty covers the cost of troubleshooting and mailing fee from the manufacturer back to you.

Make sure voltage transducers have a regulated power supply. For some reason, the power supply from 3rd floor EE Electronics labs managed to burn the supply fuse a couple of times.