HP 82479A Owner's Manual page 88

System Monitoring
The third display option is the column format. This format displays the label for each trace followed by
three columns of numbers. The columns list, in order, the lower nominal bound, the current reading, and
the upper nominal bound.
The MOH I TOF program provides two capabilities in addition to the display of data on a video monitor.
The program can log data during a monitoring session, and it can perform limit tests for control and alarm
purposes.
The data logging option allows you to store a "snapshot" of the system in a data file at regular intervals.
For example, the status of a wave-soldering system could be stored every 15 minutes during a shift. Once
the MHI TOF program is done, you can use the FEFIIFET program to generate a report on the stored
data (refer to section 11), the TRHMZF EF program to send the data to a Series 200 computer (refer to
section 12), or the M=0% FF program to send the data to an MS-DOS based computer (refer to section
13).
The limit test option allows you to use the [MH I TIFprogram for control purposes. You can specify up
to five limit tests for each trace. The program continuously checks the current value of a trace against
any limit that you have specified for it, and takes the specified limit action if the value goes past the limit.
The limit action may merely signal an operator, or it may actively control the system. Refer to subsection
7.2, "Limit Tests" for more information.
7.1 MEASUREMENT CHOICES
Each trace represents one measurement from a channel or bit in the HP 3421A. There are 20 functions
available:
SIGNALS TEMPERATURE DIGITAL
DC Volts T,E,J,K,R,S Thermocouples Digital Bit
AC Volts 2252 Ohm Thermistor (2WQ) Digital Byte
4-20mA Current 2252 Ohm Thermistor (4WQ)
2-Wire Ohms 5000 Ohm Thermistor (2WQ)
4-Wire Ohms 5000 Ohm Thermistor (4WQ)
Frequency European RTD (xx=.00385) (2WQ)
European RTD (o=.00385) (4WQ)
Most functions may call a user-written conversion program which is used to perform additional processing
on each measurement, such as a unit conversion.
As an alternative to these functions, a trace may call a user-written custom program. This allows the
user to include a measurement from a sensor or instrument that is not directly supported by the
MCI TORE program, or to create custom limit action capabilities (refer to appendix E for an example).
7-2