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User Manual 1260-14C
Module Specification 1-1
Chapter 1
MODULE SPECIFICATION
Module
Specification
The 1260-14C provides 96 Open Collector (OC) I/O lines in twelve
groups of 8 bits each. Each group of 8 bits (hereafter referred to
as a port) can be read from or written to asynchronously using the
commands READ and WRITE. Additionally, up to 12 ports may
be grouped together and synchronously operated using an
external clock for as many as 256 consecutive operations by using
the appropriate SETUP commands. The last data previously
written to or read from a port is retrieved by using the PDATAOUT
command. The current state of the 1260-14C is determined by
using the PSETUP command. Refer to the individual syntax
descriptions for each command and the examples given later for
the specifics regarding these operations.
The outputs of the 1260-14C are connected to an external voltage
that provides inductive fly-back protection. If inductive loads are
to be driven, the external voltage must be supplied to the module.
Failure to do so may cause damage to the module's output stage.
If protection for inductive voltage fly-back is unnecessary, V
ext
does
not need to be supplied to the module.
The 1260-14C allows twelve separate external voltages to be
supplied to the module's front panel. These external voltages are
supplied to the output stages on a byte-by-byte basis. This allows
some flexibility as to the OC output voltages that are supported
simultaneously by the module (see the 1260-14C Block Diagram).
Also, the VXIbus supplied voltages (+5V, +12V, and +24V) are
used to pull up the output stage if the module is fitted with internal
resistive pull-ups.
The 1260-14C includes provisions for the installation of internal
pull-up resistors. This includes twelve 16-pin DIP sockets
designed to accommodate standard 16-pin, eight resistor-isolated
style DIP packages, such as CTS P/N 761-3-R10k or Bourns P/N
4116R-001-103. The 1260-14C contains no internal pull-up
resistors at time of shipment.
It is recommended that outputs be pulled-up with 10k
Ω
resistors if
driving standard logic gates. Internal pull-ups are limited to a
minimum value of 10k
Ω
due to the amount of current available
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