Instrument Security Procedures
Models:
Fluke 8840A
Product Name:
Digital Multimeter
Instrument Description:
High performance 5-1/2 digit multimeters.
Memory Description:
Mainframe
There are three devices, with one form or another of memory, in the 8840A.
• 8-bit microcomputer, w/4k bytes of ROM and 144 bytes of RAM
• EPROM, 4k bytes
• EEPROM, 512 bytes
1. The ROM memory in the microcomputer is an “on-chip
mask-programmed” ROM and is not alterable by the user of the 8840A.
The RAM memory is cleared each time the instrument is turned off.
2. The EPROM is pre-programmed memory and is not alterable by the user.
3. The EEPROM stores the calibration constants and a user-defined string
of up to 16 ASCII characters.
Option -05, IEEE – 488 Interface
There is one device with memory in the IEEE – 488 Interface option.
• 8-bit microcomputer, w/4 k bytes of ROM and 144 bytes of RAM.
1. The ROM memory in the microcomputer is an “on-chip maskprogrammed” ROM and is not alterable by the user of the 8840A. The
RAM memory is cleared each time the instrument is turned off.
Option -09, RMS AC converter
There are no memory devices in this option.
8840A SOMV 1 of 2 11/29/2006
Memory Cleaning Instructions:
Access to the user-defined string is available ONLY over the IEEE-488 bus
[option -05]. Use the GET COMMAND, G3 to retrieve the contents of the user
defined message. To clear the message, set the instrument in the calibration
mode [by pressing the CAL ENABLE switch on the front panel] and use the PUT
COMMAND, P3 and send 16 <spaces>
To clear the entire calibration memory, set the instrument in the calibration mode
[by pressing the CAL ENABLE switch on the front panel] and use the
CALIBRATION COMMANDS, C3 and C0. This will clear the entire calibration
memory, leaving you a ‘brain-dead’ 8840A – requiring a complete calibration to
be useful again.
8840A SOMV 2 of 2 11/29/2006
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