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Laureate™ Serial Communication Options
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RS-232 interface board
Single RJ11 connector for point-to-point
data communications. |
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RS-485 interface board
Dual RJ11 connectors to
facilitate daisy-chaining for multipoint communications. Jumper selectable
2-wire (half duplex) or 4-wire (full duplex) connection. |
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Modbus RS-485 interface board
Dual RJ45 Modbus connectors
to facilitate daisy-chaining for multipoint communications. Jumper
selectable 2-wire (half duplex) or 4-wire (full duplex) connection. |
Features
- Choice of three serial data
I/O interface boards:
- RS-232 for
point-to-point communications.
- RS-485 for multipoint communications.
- Modbus RS-485 for
multipoint communications per Modbus Serial Line
Specification V1.0.
- Allows
Laureate meter or
counter to:
- Output latest value, peak value and alarm status to a
computer, PLC or remote Laureate display.
- Serve as a remote display to a computer, PLC or
another Laureate.
- Be configured (set up) via a computer using
Laurel-furnished software.
- Data rates selectable from 300 to
19,200 bps.
- Powered by
Laureate instrument.
- Isolated from meter and power
grounds.
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Description
A serial communication
option board allows a Laureate digital panel meter, scale meter, counter
or timer to be interfaced to a computer or PLC, or to or other devices
with a serial communication port, such as a Laureate
6-digit remote display or a panel-mount printer.
The transmitted data
may include the latest reading, peak value, alarm status, or setup
information. The data can be displayed, processed and data logged
by a computer or PLC. It can also be received by a Laureate
6-digit remote display, which can
display the serial data like a meter and also process the serial data to
control relays and
generate a scaled, isolated 4-20 mA or 0-10V analog output.
For detailed technical
information, please download our
Serial Communications Manual.
Choice of
three Serial Boards
1.
RS-232 Board |
Point-to-Point Communications
via
RS-232 |
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The Laureate RS-232 board features a single 6-pin RJ11 jack and is
intended for point-to-point communications with a computer, a PLC, or
other device with an RS-232 port. Normally there is only one
Laureate per RS-232 line. However, multiple 6-digit Laureate remote
displays with an RS-232 board can be connected to a single RS-232 line in multidrop fashion
and be digitally addressed.
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CBL01 cable
assembly.
With DB9 and RJ11 connectors to connect a Laureate to the
COM port of a PC. |
Combined
CBL01 and CBL02 cable assembly.
With USB and RJ11 connectors to connect a Laureate to the
USB port of a PC. |
Plugging into the Laureate is
the RJ11 connector of a common 6-wire telephone extension cable. Plugging
into the COM port of a PC is custom-wired DB9 to RJ11 adapter, which accepts the other
end of the telephone extension cable. The DB9-to-RJ11 cable
assembly is sold by Laurel as Part No. CBL01. Laurel also sells a
USB-to-DB9 adapter a Part No. CBL02. A combined CBL01 and CBL02 cable
assembly allows a Laureate to be connected to the USB port of a PC.
The RS-232 request-to-send line (RTS) can be
set to a latched mode, where a single reading is transmitted when the line is taken high
momentarily.
This mode allows a single data transfer to be commanded by another device.
2.
RS-485 Board
The
Laureate RS-485 board allows multiple Laureates plus non-Laureate devices
to be connected to the same RS-485 line in parallel,
multidrop fashion. The RS-485 board provides for up to 31 digital addresses, so that multiple Laureates
can be addressed and transmit readings on the same data line. The use of RS-485
lines optimizes utilization of computer ports and
simplifies plant wiring. In the absence of a computer,
a single Laureate device with an RS-485 board can drive
multiple Laureate 6-digit remote displays.
Transmission distances up to one mile are possible.
In case of long line lengths, the RS-485 board at
the end of the line can be terminated by a
jumper-selectable 120-ohm resistor to minimize
signal reflections. A full duplex mode with separate
wire pairs for transmit and receive is selectable,
as well as a half duplex mode with shared transmit
and receive wires. For details, please see our
Serial
Communications Manual.
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RS-485 multidrop communications |
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The Laureate RS-485 board provides two 6-pin RJ11 jacks, whose
corresponding pins are wired in parallel. This allows multiple Laureates
to be daisy-chained with no need for an RS-485 hub.
The signal levels of the
Laureate RS-485 board are fully compliant with the EIA/TIA-485 standard. Devices by different manufacturers can share the same RS-485
data line, provided that their connectors are wired appropriately. The
Laureate RS-485 board can be used with Modbus; however, the connectors will not be compliant
with the Modbus standard.
3.
Modbus RS-485 Board
The Laureate Modbus RS-485
board offers all of the benefits of the Laureate RS-485 board and is
fully compliant with the Modbus over Serial Line Specification V1.0
(2002). This includes RJ45 connectors and half or full duplex
operation (jumper selectable). A benefit of Modbus is that up to 32 devices by different manufacturers can share the same
RS-485 data line, be connected using similarly-wired RJ45 connectors,
and be addressed using the same protocol.
A computer is required in
a Modbus system. The Modbus Serial Line protocol is a master-slave protocol,
where a master node (computer) issues commands to slave nodes
(peripheral devices) on the
bus and processes responses.
The Laureate Modbus RS-485
board features two 8-pin RJ45 jacks wired in parallel, one of which
is equipped with two indicator LEDs. The Modbus protocol is implemented
by the microcomputer in the Laureate main board and is compliant with
the Modbus RTU or ASCII transmission modes.
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Laureate Software
The
following Laurel software utilizes Laureate serial
communications:
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Setup & Calibration
Software
can facilitate the setup of Laureate digital panel meters,
scale meters, counters, timers and remote displays as an alternative to
programming these devices from the front panel. It
is required to set up Laureate transmitters, which
don't have a front panel. It can be downloaded from
this website at no charge. It utilizes Laurel's
Laurel ASCII Protocol. It's use requires an external
PC and a serial communications board in the meter. Following setup, this board can
be removed if desired.
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Custom Curve Linearizing
Software is applicable to the Extended option
version of all Laureate digital panel meters,
counters and timers, excluding only temperature
meters (the latter already include preset
linearization).
Custom curve linearization can provide exceptional
accuracy from low cost transducers and extend their working range on the high and low ends. It can also solve special
application problems where there is a non-linear relationship between
the input and desired readout. This software can be downloaded from this
website at no charge. It utilizes Laurel's Custom
ASCII Protocol. Its use requires an external
PC and a serial communication board. Following
setup, this board can be removed from the Laureate.
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Data Logging
Software can turn a
PC into a powerful, low-cost data logging system when connected up to 31
Laureate instruments. These can be any mix
of digital panel meters, counters and timers. Data can be displayed on the
computer screen in the form of up to 64 actual or
virtual
panel meters in 4 groups (or screens) of up to 16
meters each. Data can be logged from selected
meters into an ASCII file, which can then be easily imported into MS Excel for
graphing and analysis. The logging time interval is user selectable.
Requirements include an
external PC with a free COM port, and RS-232 to
RS-485 converter for multiple instruments, and a serial communications
board in the meter. A modest software license fee applies.
Laurel's Data Logging software works with Laurels
Laurel ASCII Protocol, not with the Modbus Protocol.
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Hardware Specifications
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RS-232 Board |
Connection
Data Rates
No. of devices on data line
Connector
Standards Compliance |
RX, TX, GND, RTS (optional)
300, 600, 1200, 2400, 4800, 9600, 19200 bps
1 (point-to-point)
Single RJ11 jack
EIA/TIA-232 |
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RS-485 Board |
Modes
Data Rates
No. of devices on data line
Connectors
Standards Compliance |
Full
duplex (4-wire) or half duplex (2-wire)
300, 600, 1200, 2400, 4800, 9600, 19200 bps
31 max
Two RJ11 jacks wired in parallel for daisy-chaining
EIA/TIA-485 |
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RS-485 Modbus Board |
Modes
Data Rates
No. of devices on data line
No. of digital addresses
Connectors
Standards Compliance |
Full
duplex (4-wire) or half duplex (2-wire)
300, 600, 1200, 2400, 4800, 9600, 19200 bps
32 max
247 max
Two RJ45 jacks wired in parallel for daisy-chaining
Modbus over Serial Line Specification V1.0 (2002) |
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Electrical specs applicable to all three
boards |
ESD Protection
EMI Immunity
EFT Protection
Short Circuit Protection |
15 kV per IEC 1000-4-2
10 V/m per IEC 1000-4-3
2 kV per IEC 1000-4-4
Continuous |
Protocol Specifications
(Implemented by meter main board)
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Laurel ASCII |
Data Format
Protocol
Applicable boards
Main Board Revision Level |
No parity, 8 data bits, 1 stop bit
Laurel Laurel ASCII
RS-232, RS-485, Modbus-RS-485
Any |
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Modbus RTU |
Standards Compliance
Data Formats (selectable)
Applicable Boards
Main Board Revision Level |
Modbus over Serial Line Specification V1.0 (2002)
1. No parity, 8 data bits, 2 stop bits
2. Odd parity, 8 data bits, 1 stop bit
3. Even parity, 8 data bits, 1 stop bit
RS-232, RS-485, Modbus RS-485
Level 5 or above |
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Modbus ASCII |
Standards Compliance
Data Formats (selectable)
Applicable Boards
Main Board Revision Level |
Modbus over Serial Line Specification V1.0 (2002)
1. No parity, 7 data bits, 2 stop bits
2. Odd parity, 7 data bits, 1 stop bit
3. Even parity, 7 data bits, 1 stop bit
RS-232, RS-485, Modbus RS-485
Level 5 or above |
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