Welch Allyn Atlas Service Manual page 21

Section 2 - Service
2.3.6 TEMPERATURE
MEASUREMENT
SUBSYSTEM
CALIBRATION
12 WELCH ALLYN ATLAS MONITOR
2.3.6 TEMPERATURE MEASUREMENT
SUBSYSTEM CALIBRATION:
Need:
PC
Serial Cable
HyperTerminal
1kOhm - 2kOhm 1% 1/2watt resistor
Large RCA plug (1/4") 2 conductor
Short length of wire (optional)
Soldering iron and solder
2.3.6.1Prepare Resistor/Plug assembly.
Solder the resistor across RCA plug
terminals.
2.3.6.2 Plug the resistor assembly into the Atlas
Temperature jack.
2.3.6.3 Connect the Atlas to the PC serial port.
2.3.6.4 Turn the Atlas ON.
NOTE: Temperature display will show a valid
temperature.
2.3.6.5 Start HyperTerminal on the PC.
2.3.6.6 At the Pangea prompt, type:
Pangea>temp cal xxxxxx<ENTER>
(where the xxxxxx is the value of the precision resistor
in centiOhms- Specify the Ohms, tenths, and
hundredths of Ohms with no decimal point- for
example, a 1200.00 Ohm resistor would be:
Pangea>temp cal 120000<ENTER>
2.3.6.7 Wait four seconds then type:
Pangea>temp state<ENTER>
2.3.6.8 Displayed resistance will be within 0.5
Ohms of the value that you entered.
The Offset should not exceed 5.0 Ohms.
NOTE: The system will silently fail (without error) if it
is unable to calibrate properly. Therefore you
must manually verify that this resistance is
correct.
2.3.6.9 Turn the Atlas OFF.
2.3.6.10Unplug the resistor/plug assembly.
2.3.6.11 Remove the serial cable.
2.3.6.12Check the accuracy of the
temperature sensing system using the
process described in Section 2.2.11
SERVICE MANUAL 6200-43E REV. A