CALAMP WIRELESS NETWORKS INC. MCUC5 Manual Do Utilizador

 

The Integra-T is designed for fully transparent
operation. This means that all binary values are
transmitted as data, with minimum time delays,
and without regard to their binary value.
“Break” signals can also be transmitted.

 

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

 

The Integra-T 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 the Integra-T to turn on its transmit-
ter. CTS is raised 4 ms later to accommo-
date DTE that requires a CTS transition be-
fore it can send data. The transmission will
continue until RTS is dropped, or until the
Tx Timeout  (see section 2.8.4) expires.

 

CTS is used as a handshaking/flow control sig-
nal in both modes. If the Integra’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, adjust the DTE
baud rate so that the 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.

 

The Integra-T may be configured to send
“break” signals, as required by some SCADA
protocols. A break signal is generated by hold-
ing TXD in the zero state for longer than one
character time. Indication of a break signal is
carried in a special data transmission to the re-
mote station, which in turn generates its own
output break signal.

 

At a port speed of 9600 b/s the output break sig-
nal 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. The Integra-T 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 – 9600 b/s. Baud rate is set using the
Integra-T RSS and is independent of the net-
work baud rate setting. However, with COM
port set to 300 bauds, the network speed should
not be set higher  than 4800 b/s.

 

We recommend that the COM port baud rate
be set to a speed not greater than the RF
network baud rate. Setting a COM port baud
rate higher than the network rate may result in
data buffers filling, which in turn may cause the
Integra-T to drop CTS. This could have detri-
mental 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-T RSS. These pa-
rameters may be set differently on various Inte-
gra-T units without affecting their ability to
communicate 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-