CALAMP WIRELESS NETWORKS INC. MCUB5R Manual De Usuario

 

Unlike most transparent radiomodems, Inte-
gra-TR eliminates “bit dribble” and allows DOX
operation. A CRC-16 error check is used so that
faulty data will not be delivered.

 

Integra-TR has two operating modes, for its
COM port: (selectable via the RSS program)

 

DOX mode: The RS-232 port is monitored for

incoming data. Upon receipt of the first data
byte, the transmitter is turned on. The RTS
signal is ignored (note: RTS may still be
used as a wakeup signal for a unit that is
asleep).

 

RTS mode: The RTS signal is monitored for a

low–to–high transition. This transition
causes Integra-T to turn on its transmitter.
CTS is raised 4 ms later to accommodate
DTE that requires a CTS transition before it
can send data. The transmission will con-
tinue until RTS is dropped, or until the Tx
Timeout  (see section 2.9) expires.

 

CTS is used as a handshaking/flow control sig-
nal in both modes. If Integra-T’s buffers fill,
CTS will be dropped as a signal to the DTE to
stop sending data. This condition is most likely
when the Data port speed exceeds the radio
network speed. In such cases, reduce the DTE
baud rate so that Integra-T buffers will not fill.

 

The data forwarding timer can modify the tim-
ing between data blocks in a transmission to
accommodate some RTU’s special timing re-
quirements. Set to “normal” (15 ms) unless ad-
vised otherwise by technical support. Do not use
“fast” (5 ms) timer below 2400 b/s.

 

Integra-TR may be configured to send “break”
signals, as required by some SCADA user pro-
tocols. A break signal is generated by holding
TXD in the zero state for longer than one char-
acter time. Indication of a break signal is carried
in a special data transmission to the remote sta-
tion, which in turn generates its own output
break signal.

 

At a port speed of 9600 b/s, the output break
signal has a duration of 10 to 20 ms, regardless
of the duration of the input break signal. These
times are scaled proportionally for other baud
rates. Integra-TR may also be set to ignore
“break” signals in order to prevent spurious
transmissions when terminal equipment is pow-
ered on and off.

 

The COM port operates at standard baud rates
from 300 – 19200 b/s. Baud rate is set using the
Integra RSS and is independent of the network
speed setting.

 

We recommend that the COM port baud rate
be set to a speed not greater than the network
speed. Setting a COM port baud rate higher than
the network rate may result in data buffers fill-
ing, which in turn may cause Integra-TR to drop
CTS. This could have detrimental effects on
some protocols, particularly those that ignore
CTS.

 

The COM port will support 7 or 8 data bits, one
or two stop bits, and even, odd or no parity. Se-
lection is made via Integra RSS. These parame-
ters may be set differently on various Integra-T
units without affecting their ability to communi-
cate with each other.

 

Online diagnostics may be included as part of an
extended header at the beginning of each trans-
mission. It may be enabled or disabled on a per-
unit basis without affecting inter–commun-
ication. Reception of online diagnostics is al-
ways enabled.

 

Enabling this option adds about 5 ms delay at
9600 b/s (10 ms at 4800 b/s) to each trans-
mission, but has no other effect on network op-
eration.

 

Online diagnostics for all audible stations is de-
livered out at the Setup Port. An ASCII diag-
nostic output is also available. Diagnostic in-
formation is normally collected at the master
station.