Owner`s manual

103
12 V50/V73/V74/V75/V76/V86/V87
GENERAL INFORMATION
The V50, V73, V74, V75, V76, V86 and V87 I/O modules
are used in conjunction with a host module. The V74
has four EIA-232 serial ports, the V75 has four
selectable EIA-232/EIA-422 serial ports, the V76 has
four current loop ports, and the V86 and V87 have four
selectable EIA-422/EIA-485 serial ports. The V50 has 4
isolated EIA-232 ports and the V73 has 4 EIA-232 ports
where the voltage signals are TTL levels.
These modules allow a host computer system connected
to the V71 host module to individually select up to four
peripheral devices (e.g., bar code readers, security
systems, digital instruments, etc.) and send data to the
selected device. The V50/V73/V74/V75/V76/V86/V87
modules simultaneously multiplex incoming data from
the peripheral devices to be transmitted to the host
system. The method of data transmission from the
peripheral devices to the host system is dependent
upon the mode of operation. Each 4-port serial module
features four user-selectable modes of operation. The
modes of operation are:
Full Duplex Mode - Allows the V71 host module to
switch between four peripheral devices and provides
bidirectional data transfer between the host module and
the selected peripheral device. Data received from non-
selected peripheral devices is stored in a buffer until the
port is selected by the host system.
Immediate Message Mode - Provides automatic message
multiplexing from all peripheral devices. Data is
buffered until a terminating character is received or
2048 characters are received. Messages are then sent
to the host computer preceded by a port identification
code and optional time tag.