AMETEK CTS 3.0 - Manual (Page 157)

User Manual Compliance Test System 3.0
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18. Principle Of Operation
18.1 General
The Compliance Test System is a power measurement and power analyzer system. The three
basic building blocks are:
AC power, either line power or, typically, a CI power source to provide the proper voltage and
frequency for the test at hand.
PACS-1 or PACS-3 measurement unit. This device measures the actual current and voltages
under test and conditions the signals to be compatible with the Analog to Digital data
conversion card.
CTS 3.0 Software. The software is the final link to the user. It translates the data from the AD
card into viewable and readable measurements in a GUI format.
18.2 AC Power
The AC power is the most flexible of the building blocks. It can be 1-phase or 3-phase and in some
cases the users available line power is adequate. However, if more precise control of voltage and
frequency is needed, as in IEC regulatory testing, the California Instruments mating power sources
provide the proper accuracy and programmability for this task.
18.3 PACS1 or PACS3 Measurement Unit
The PACS measurements module uses Hall Effect current sensors to isolate and scale a sense
voltage that is an accurate and linear function of the current being measured. The sensing
amplifiers uses differential sensing to reduce common mode noise pick-up before it is sent to the
interface connector for transmission to the host PC.
To sense the applied voltage, another set of differential amplifiers are used together with high
precision sense resistors to provide high CMRR. The sense resistors are of high enough
impedance to limit any leakage current to under 0.5mA.
The PACS-1 module also has circuits that switch the built in impedance in and out of circuit for
flicker compliance testing. If this optional impedance is not installed, the “flicker/bypass” button
control has no function.
18.4 CTS 3.0 Software
The CTS 3.0 Software is designed to work with the da ta acquisition card‟s digital samples of voltage
and current. Numerous data channels are scanned sequentially and the software then calculates
many parameters using Fast Fourier Transforms and displays them in the Graphical User Interface.
In addition to numerical outputs of voltage current, power etc., the software also displays real time
graphics of voltage and current.