Measurement Computing Digital488/80A - Manual (Page 8)

HVCX1 High Voltage/Current Interface Option
The HVCX1 option permits the I/O lines to be configured as high voltage (up to 50 V) inputs or as high
voltage/high current outputs (up to 200 mA sink capability) to allow interfacing with solenoids, switching
relays and other high voltage/high current devices using an external voltage source. It allows interfacing to
non-TTL level devices by offering compatibility with 12, 24 and 48 volt logic. The individual 8-bit ports
can be configured to control high current open collector drivers. Each high current driver has an internal
fly-back diode for protection when switching inductive devices such as relays. When the HVCX1 option is
used, the six handshake and control lines can also interface to 12, 24, or 48 volt logic.
Power-Up & Setup Configuration
The Digital488/80A allows up to 100 configurations for each channel to be created. The configurations are
stored in non-volatile memory, which enables the input/output status and logic level of every I/O line to be
defined when power is applied. The configurations can be called from a single pre-defined command from
the IEEE 488 controller. This allows easy configuration of the device for a variety of applications.
Internal pull-up resistors ensure a logic "high" the instant power is applied. When using the HVCX1
option with high current driver outputs, the internal pull-up resistors ensure that the high current driver
outputs are switched off the instant power is applied -- a requirement for process control applications.
Internal Buffer
A built-in data buffer in the Digital488/80A can store up to 8,000 bytes, which is large enough to capture
two thousand patterns from one 40-bit I/O channel. When interfacing to slow devices, the data buffer
relieves the controller of the need to constantly read data from the Digital488/80A.
Software Programmable Features
The software programmable features on the Digital488/80A include data formats, individual bit set and bit
clear commands and terminators. The six available data formats are ASCII hexadecimal, ASCII character,
ASCII binary, binary, high speed binary and ASCII decimal. The programmable terminators facilitate
interfacing to various controllers. Using the User Status (
U ) command, the controller can check the
programmed status of the Digital488/80A at any time. With the Query ( ? ) option offered with each
Digital488/80A command, user-defined status command strings can be built to request the status
information needed for a given application.
Accessories
Additional accessories that can be ordered for the Digital488/80A include:
• CA-1: Power cable
• CA-7-1: 1.5-foot IEEE 488 cable
• CA-7-3: 6-foot shielded IEEE 488 cable
• CA-7-4: 6-foot reverse entry IEEE 488 cable
• CA-88: 6-foot 50-pin D-shell ribbon cable
• CN-20: Right-angle IEEE 488 adapter, male and female
• CN-22: IEEE 488 multi-tap bus strip, four female connectors in parallel
• CN-23: IEEE 488 panel-mount feed-through connector, male and female
2 Digital488/80A Overview 11-07-02 Digital488/80A User's Manual