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Appendix A. Installation and Maintenance
HP-IB Logic Levels
CAUTION HP products delivered now are equipped with connectors having ISO
metric-threaded lock screws and stud mounts (ISO M3.5×0.6) that are
black in color. Earlier connectors may have lock screws and stud
mountswith English-threadedlock screwsandstud mounts (6-32 UNC)
that have a shiny nickel finish.
CAUTION It is recommended that you do not stack more than three connectors,
one on top of the other.
Hand-tighten the connector lock screws. Do not use a screwdriver.
A.8 HP-IB Logic Levels
The instruemnt’s HP-IB lines use standard TTL logic, as follows:
• True = Low = digital ground or 0 Vdc to 0.4 Vdc
• False = High = open or 2.5 Vdc to 5 Vdc
All HP-IB lines have LOW assertion states. High states are held at
3.0 Vdc by pull-ups within the instrument. When a line functions as
an input, it requires approximately 3.2 mA to pull it low through a
closure to digital ground. When a line functions as an output, it will
sink up to 48 mA in the low state and approximately 0.6 mA in the
high state.
NOTE The HP-IB line screens are not isolated from ground.
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