Chiller Performance, Power and Ambient Condition Data Acquisition
using the IL-Mini™
The IL-Mini™ data logger coupled with one or more WNC Modbus output power meters results in a flexible, stand-alone, multi-parameter electrical power data acquisition system. Shown below is the IL-Mini™ logging electrical parameters from two 3-phase electrical loads. In the following Chiller Performance Analysis application, logging electrical parameters from the cooling tower fan(s), pump(s) and chiller compressor is readily handled with a single IL-Mini™ Data Logger and multiple Modbus networked electrical meters. This frees up the IL-Mini™ analog channels for additional sensor inputs such as temperature, flow, humidity, etc.
The WNC Modbus enabled electrical meter is configured as a Modbus Slave device, assigned a network address and connected to the high-voltage electrical service or load to be measured. The WNC requires electrical voltage sensing connections to each of the phases as well as current transformers (CT’s) for current measurement on each of the phase conductors. The WNC power meter runs autonomously sampling the phase voltages and currents very quickly, calculating phase voltages, phase currents, Power Factor, instantaneous power and a multitude of other electrical parameters. The WNC updates internal memory registers with these values as they are calculated.
The IL-Mini™ data logger enabled with the Modbus RTU Master option is connected to the WNC meter(s) via a twisted wire pair in a daisy chain configuration. During operation, the IL-Mini™ reads the WNC Slave device registers containing the electrical parameters and uses them in the Program Net per the user’s configuration, logging them to memory, performing calculations, alarming and more.
In addition to the Modbus interface, the IL-Mini™ also has 4 analog input channels and one digital input (Event, Counter or Frequency) to which other transducer and signal inputs can be connected for simultaneous data acquisition as in the following chiller monitoring example.
To configure the IL-Mini™ for the desired data acquisition and alarming functions, a program is built within the Logic Beach HyperWare-II software. This program is called a “Program Net” as it consists of a number of icons all visually connected together with a mouse to make a “network”. The Program Net is then uploaded to the IL-Mini™ memory where it executes. Due to the intuitive flexibility of the HyperWare-II software, there are unlimited data acquisition schemes that can be implemented with the Program Net.
Below is a Program Net that acquires electrical, temperature and humidity performance data on a vapor compression chiller system. Parameters measured and logged include: