Meters are calibrated on conventional production calibration racks and ensure a reduction in the meter bill-of-materials (BOM). The calibration concept requires the use of 2 primary components, the AS8118 orAS8168 1-phase meter IC from austriamicrosystems and the PTCS-81×8 automatic calibration interface from PowerTech.
The AS8118 and AS8168 single phase energy metering ICs offer fast automatic on-chip digital calibration with 0.1% active energy error over a 1000:1 dynamic range. A wide calibration range ensures that calibration errors of over 50% can be accommodated. These ICs directly drive a stepper motor as well as a kWh LED output, or may be interfaced to a micro-controller unit (MCU). The PTCS-81×8 automatic calibration interface which is installed on conventional calibration racking systems, connects the calibration rack to over 24 meters simultaneously. The calibration interface programs all variable meter parameters into the IC, thus meeting individual utility needs. The parameters include:
• Meter system calibration with no resistor network required
• Input gain selection for use with shunt or current transformer
• Anti-creep threshold selection
• kWh LED pulse rate selection
• Stepper motor pulse rate selection
• Fast calibration pulse rate selection.
This user-friendly interface ensures that the calibration procedure is initiated by pressing a single pushbutton. All meters are calibrated within seconds and the programmed values can reprogrammed if required. The programmed values are only accessible via a password to prevent operator access. The AS8118 and AS8168 ICs ensure consistent precision calibration to 0.1% error. The fast and simple on-chip automatic calibration procedure requires no additional labour skills to achieve over 40% increase in meter throughput. Meter parameters can thus be very easily changed, without disruption to the production process.