41
Reporting the Checksum Status
The checksum indicates the status of the unit’s A/D converter calibration. To report the status of the
checksum, enter:
R52
The controller responds with the message:
[CS
value
]
where
value
: 0 = OK
1 = Error Condition
If the controller detects a checksum error, perform a full calibration to correct the problem. Refer to
descriptions of how to calibrate the full scale of the analog setpoint, zero the analog set, and calibrate the span
of the A/D converter (page 41).
Note
If the checksum error persists after you perform a full system calibration the error indicates a
hardware failure of the EEPROM. Contact an MKS Service Center, listed on the inside back
cover of this manual, for assistance.
Calibrating the A/D Converter
The controller’s A/D (analog-to-digital) converter converts the analog input to a digital value that the
controller uses. The span of the A/D converter is calibrated at the factory. You may need to recalibrate the
span if the controller issues a checksum error when you power it up, or if the transducer’s readings are
incorrect.
To calibrate the span for the 10 V sensor range:
1. To verify the setup to 10 V for 10 V full scale, issue the R35 command and receive the G2 response. If
the setup is not 10 V, use the G2 command to set up accordingly.
2. Select either the Hi or Lo sensor and Lock Hi or Lock Lo.
3. Apply a known voltage of Full Scale (e.g. 10 Volts DC) to the pressure input pins (1 (plus) and 8
(ground) on a 9 pin connector; pin 2 (plus) and pin 12 (ground) on a 15 pin connector) on the connector of
the selected channel (Hi or Lo).
4. Send the command:
Y3
Calibrating the span of the A/D converter may take up to 5 seconds.
5. Check that the calibration is finished by sending the checksum error request:
R52
Immediately after the span calibration is complete, the controller responds with the message:
CS
value
where
value
: 0 = OK
1 = Error Condition
To calibrate the zero of the A/D, apply a know 0 VDC to the sensor input pins and send the command:
Y4
