©
Page 58 of 97
Issue: 1.04
7 Calibration
The ADC and measurement topology used in the microK are inherently very
stable with both time and temperature. The stability of the microK is primarily
determined by its internal standards (a zener reference for voltage and bulk metal
foil resistors for resistance). We have used the best available components for
these internal standards; a Linear Technology precision zener reference of the
type used for voltage transfer standards in electrical metrology and Vishay
hermetically sealed bulk metal foil resistors. To keep your microK operating
within its performance specification, it should be recalibrated annually. Please
contact Isothermal technology to arrange this calibration.
7.1 Checking Calibration
The calibration can be checked by measuring known standards with the microK.
The calibration should be performed in a temperature controlled environment
between 19°C and 25°C. The microK should be powered up and left to stabilise
in the calibration environment for at least 4 hours before checking or adjusting its
calibration.
7.1.1 Checking the Master Current Source
The microK current source has 3 ranges (0-0.1mA, 0-1mA and 0-10mA). Check
these by connecting a calibrated ammeter (or DMM) across the current terminals
of channel 1 and connecting both the sense inputs to the red current terminal:
V
I
A
Checking the master current source involves connecting a PC to your microK
(using a null-modem RS232 cable) and sending commands to it from
Hyperterminal (part of the standard Windows operating system installation) or
