© Isothermal Technology
Page 57 of 102
923 milliK manual - issue: 1.10
5 Calibration
The calibration of your milliK can be checked by applying standards to the inputs and noting
the indicated readings.
The milliK includes calibration software that allows you to adjust its calibration. The process
involves attaching suitable standards to the inputs and entering the values of these standards,
the calibration software then monitors the measured values and applies any required
corrections. The calibration data is stored in an internal comma-separated variable (CSV) file
that includes the whole calibration history (time/date stamped) back to its original factory
calibration. The calibration file can be exported to a USB drive so that it can be read (for
example, by importing it into Microsoft Excel™). The calibration software requires you to
enter additional information (such as model/serial numbers of the standards used) in order to
document the calibration history of your milliK.
Typically a calibration process will involve measuring the pre-adjustment calibration of the
milliK, then making any necessary calibration adjustments and finally checking the
calibration after adjustment. The calibration should be checked or adjusted in a temperature
controlled environment between 19 and 25°C. The milliK should be powered up (press the
Start key (F4) in the opening screen to ensure that the measurement system is initialised and
running) and left to stabilise in the calibration environment for at least 3 hours before
checking or adjusting its calibration.
All of the adjustment is implemented in software (there are no adjustment potentiometers
inside the milliK so as to maximise reliability and provide adjustment that does not drift with
time or temperature). The milliK provides the following software adjustments:
Gain adjustment for the 115
Ω
range
Gain adjustment for the 460
Ω
range
Gain adjustment for the 500k
Ω
range
Voltage offset adjustment for Channel 1
Voltage offset adjustment for Channel 2
Gain adjustment for the 115mV range
Gain adjustment for the 30mA (4-20mA input) range
Offset adjustment for the internal reference junction sensor
The gain adjustments are common to all channels. There are no zero adjustments for the
resistance ranges since the zero readings are more than adequate (by design) without the need
for any adjustment.
