Design and development of a novel multichannel data acquisition system using labview for an automobile air conditioning application

To sustain in the ever-changing environment and to combat the atmospheric effect, development of a highly efficient and an environment friendly air conditioning system which can run in parallel or as an alternative to an existing vapor compression system is the need of the hour and such novel hybrid air conditioning system are under development today. For the parameters attribution mapping of such novel hybrid air conditioning system, todays commercially available data acquisition systems (DAS) need to be customized to the requirements of addition of sensor nodes and their integration with triggering mechanism for actuation of devices for its programmed operation. Therefore, this paper describes the design and development of novel multichannel data acquisition system (NMDAS) for automobile air conditioning application. The details of the hardware design, software design, error analysis and testing of the NMDAS are presented. The proposed NMDAS uses PLC module DVP16SP configured with analog reader DVP 04TC for temperature measurement at 32 nodes and DVP04AD for pressure or humidity measurements at 8 nodes. The triggering circuit for activation of the relay is enabled using NI LabVIEW user interface and PLC data. The output of the NMDAS is integrated with processor by RS 232 port for data storage and processing. The error analysis of temperature, pressure and humidity measurements are done by comparing with reference calibration standards. The average thermal stability of the temperature sensors over the operating range of -5 degrees C to 150 degrees C is 0.0015 degrees C. The average accuracy of pressure transmitters for operating range of pressure 0 to 40bar is estimated 98.219%. The minimum error in the output current is 0.375% and maximum error is 7.125% over relative humidity span of 0%RH to 100% RH respectively. The proposed NMDAS is used for testing of the novel hybrid air conditioning system of automobile during development stage and is found expedient.