User guide

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8.1.3 REMOTE
CONTROL
8.1.3.1 Hardware settings
The RS-232 serial connection to the Veloce is made through a DB-9 connector located on the front of the
rack mount chassis. The Veloce is equipped with a RS-232 internal switch to give access to each module
from one single RS-232 serial link.
If your computer is equipped with a DB-9 serial port connector, then use a standard RS-232 extension
cable (all wires straight through). If your computer is equipped with a DB-25 connector, use a DB-25 to
DB-9 converter module with a standard RS-232 extension cable. NOTE: do not use a null modem
cable or adapter. The serial link must be configured as follow:
BAUD RATE: 9600
PARITY: NONE
DATA BITS: 8
STOP BIT: 1
8.1.3.2 Hardware flow control
The Veloce makes use of hardware flow control Handshaking based on RTS/CTS control. When
activated, the Request To Send (RTS) line of the serial link informs the Veloce that the UART of the host
computer or controlling instrument is ready to exchange data (=Computer Ready). The Clear To Send
(CTS) line indicates, when activated, that the Veloce is ready to exchange data (= Veloce Ready).
8.1.3.3 RS-232 Switches
The Veloce is equipped with two cascaded RS-232 switches to
give easy access to any of the eight plug-in modules from one
single RS-232 connector (Figure besides). It is required to first
establish the link between the DB-9 connecting port and the
module with which the communication needs to be established.
Once the communication is established, then commands can be
sent and received between the host computer and the selected
module. The switch looks continuously for a four character code
by monitoring the data that is being received from the host
computer. The switch requires a four-character preamble code to
turn on and off a port. The first character must be the ASCII escape character (decimal 27). The second
character is the ASCII character STX (decimal 2). The third and fourth characters are used to select the
port associated to the proper module. The commands required to establish the connection to each module
are given in the table below. Once the connection is established, the Remote Control Commands are sent
to the selected module and data are received from as long as the switch doesn't catch a new command
for establishing a new connection.
BA AABB AB
BD ADBE AE
Module 5 Module 1
Module 8
RS-232
Link
Module 4
Module 6 Module 2
Module 7 Module 3