ASP sterrad NX, Service & Troubleshooting Manual

Page: 121 / 126

System Calibration and Verification
7
6. “Set Bath Temperature to…” 60.0º, 70.0º, and 85.0º C are displayed
in turn and the same steps followed until the last temperature in the
series has been calibrated.
The 50.0º C and 70.0º C values are used by the system to verify the
calibration data. The system independently calculates the calibration
coefficients of the Steinhart-Hart equation for each thermistor, using the
two extreme points and the center point as inputs to the equation.
Calculated coefficients are stored in NVRAM if the data from the
50.0º C and 70.0º C tests are within 0.5º C of the model using the
calculated coefficients.
If the calibration is successful and the verification points are inside the
acceptable range (<0.5º C) the software does the following:
♦
Opens the file tempcMMDDYYhhmm (path is /ide/tempcal).
MM=month, DD=day, YY=year, hh=hour, mm=minute.
♦
Stores the following information in the file: the current timestamp
(MM/DD/YY HH:MM), R, A, B, C, both calculated verification
points (50.0ºC and 70.0ºC), last verified dates and status (PASS).
♦
The software exits the calibration screen and stores the calculated
coefficients into NVRAM. The values in NVRAM are used until the
next successful calibration.
If the verification points are outside or equal to the acceptable range
(
≥
0.5ºC) the software does the following:
♦
Opens the file tempcMMDDYYhhmm (path is /ide/tempcal)
MM=month, DD=day, YY=year, hh=hour, mm=minute.
♦
Stores the following information in the file: the current timestamp
(MM/DD/YY HH:MM), R, A, B, C, both calculated verification
points (50.0ºC and 70.0ºC), last verified dates and status (FAIL).
♦
The software exits the calibration screen and returns back to
coefficients that existed before the temperature calibration
began. The software uses manufacturing defaults if a calibration
has never been executed.
9. Press BACK during calibration to exit the current test All data from
a calibration is then lost and the system reverts to the previous
coefficients in use before the calibration was attempted or canceled.
STERRAD
®
NX
™
Service Guide 121