Rice Lake SCT-1100, Technical Manual

Page: 58 / 88

54 SCT-1100 Weight Transmitter
6.2 Serial Outputs
The instrument has two bidirectional serial outputs which are ASCII code compatible with most printers, remote
displays, PCs and other devices. See Section 2.6 on page 10 for connection information.
Transmission of data through the serial ports can be configured in the parameters  ,  and  in
the setup mode. See Section 6.3 on page 55
.
6.2.1 COM1 Serial Port
The COM1 serial port is bi-directional (half duplex) and uses RS-485 for transmitting data. It is mainly used to
connect PCs, PLCs and additional remote displays. The transmission speed may be selected in the setup as: 1200,
2400, 4800, 9600, 19200, 38400, 57600, 115200 baud (bit/sec).
On the same RS-485 line, it is possible to connect up to 32 devices (instruments, RS-485/RS-232 signal converter).
Considerations when making RS-485 connections:
• Use an
STP
(Shielded Twisted Pair) cable to make the connection (twisted and shielded pair(s) with single
shielding for each pair through aluminum band and total shielding through external shielding)
• Using 2x24 AWG duplex cable with external shielding, the RS-485 cable should not exceed 3937' (1200 m).
See Section 2.3 on page 7 .
• With very long cables, cable capacity becomes a dominant factor in power consumption (normally near
50pF/m) and this increases when speed is increased; i.e. the maximum distance can’t be covered with the
maximum possible speed.

RS-485 Serial Address – In the

functioning mode it is possible to enable the RS-485 protocol and link its
address to the instrument; the instrument then repeats the weight if the address in the received string is the same
as set here
NOTE: The parameter displays only in the secondary mode, when

is selected as the functioning
mode and the

is set to

,

or

.

RS-485 protocol is disabled

RS-485 protocol is enabled; prompt to enter the RS-485 address displays,

in which

is the RS-485 address; enter the RS-485 address (00 to 99 in repeater mode);
Press the or to increases or decrease the digit and select the digit to be modified;
when complete, confirm the address by pressing

Communication time out – When in the

functioning mode the communication time out can be set; Once the
alloted time has passed with no communication, the center segments of the LED display. Default 01.5 sec
NOTE: MAX=20.0 sec; MIN=00.5 sec
This parameter displays when

mode is selected in the secondary instrument.
Terminal Position Indicator Serial Line
TX+/RX+ 22A(+)
TX-/RX 23B(-)
Table 6-3. RS-485 Connections
Baud Rate (bit/sec) Total Cable Capacity (pF)
1200 400000
2400 200000
4800 100000
9600 50000
19200 25000
38400 12000
57600 8000
115200 4000
Table 6-4. Cable Capacity
Parameter Settings Description
Table 6-2. Serial Menu Parameters and Settings (Continued)