HP 8153A - Page 209

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.
HP-IB Logic Levels
The HP 8153A HP-IB lines use standard TTL logic, as follows:
■ True = Low = digital ground or OVdc to 0.4Vdc
■ False “ High = open or 2.5Vdc to 5Vdc
All HP-IB lines have LOW assertion states. High states are held at 3.OVdc by
pull-ups within the instrument. When a line functions as an input, it requires
approximately 3.2mA to pull it low through a closure to digital ground. When
a line functions as an output, it will sink up to 48mA in the low state and
approximately 0.6mA in the high state.
Note The HP-IB line screens are not isolated from ground.
Removing and Fitting Modules
The unit can fit two single width modules, or one double width module.
How to Remove a Module
Caution
■ Do not use the electrical or optical connectors to pull the
module out of the instrument, as this can cause damage to the
connectors.
■ Make sure that the line power is switched off before you
remove a module.
Installation A-7