The Laureate P/N LMOD interface board with dual RJ45 jacks allows multiple Laureate meters, counters, timers and remote displays to be connected to the same RS485 line.
The LMOD board is not recommended for new designs, but it remains readily available from Laurel for existing designs. For new designs, use the functionally equivalent L485 board with dual RJ11 jacks. That board is better supported by Laurel interface cables and is designed for easy interface to Laurels gateway boards, which are LUSB485, LNET485, LNET1485, LWIFI485, LWFIX485. The gateways boards all provide an RJ11 jack for connection to an RS585 bus with up to 31 Laureate instruments.
The dual jacks of the LMOD board are wired in parallel as for the recommended L485 board. This allows multiple instruments to be daisy-chaned using data cables (or patch cords) with RJ45 plugs; however, such data cables are not available from Laurel. Laurel's alternative L485 board with dual RJ11 jacks is supported by our RS485-to-USB converter cable (P/N CBL06) for data I/O and for programming by a PC running our Instrument Setup (IS) software. It is also supported by our 6-wire data cables (or patch cords) with RJ11 plugs (P/N CBL03) to daisy-chain meters without use of a hub.
The LMOD or L485 boards can be configured for full-duplex or half-duplex operation using jumpers. Transmission distances up to one mile are possible.To avoid signal reflection with long signal lines, a 120-ohm termination resistor can be slected via jumpers. The meter, counter or timer should be programmed for full duplex operation, even if the RS485 board is jumpered for half duplex.
Two serial protocols are user-selectable for RS485: Modbus RTU and Custom ASCII. For detailed information on our protocols, please see our communication user manuals.
The signal levels of tLaureate RS485 boards are compliant with the EIA/TIA-485 standard. Devices by different manufacturers can share the same RS485 data line, provided that their connectors are wired appropriately.
RS485 RJ11 Board Specifications | |
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Laurel Part Number | LMOD |
Connection | Full duplex (ATX, ARX, BTX, BRX) or |
half duplex (ATX / ARX, BTX / BRX) | |
Data rates | 300, 600, 1200, 2400, 4800, 9600 baud |
No. of devices on data line | Up to 31 without a repeater, 247 Modbus addresses |
Connectors | Dual RJ11 jacks for daisy chaining without a hub |
Line length, max | Up to 5000 feet (1500 meters) at 9600 baud depending on cable |
Isolation | 250V rms working, 2.3 kV rms per 1 min test |
ESD Protection | 15 kV per IEC 1000-4-2 |
EMI Immunity | 10 V/m per IEC 1000-4-3 |
EFT Protection | 2 kV per IEC 1000-4-4s |
Short Circuit Protection | Continuous |
Selectable Protocols | Modbus RTU, Custom Laurel ASCII |
Modbus RTU Protocol | |
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Standards Compliance | Modbus over Serial Line Specification V1.0 (2002) |
Protocol Type | Master-slave, query-response command mode |
Data Streaming Mode | Not supported by Modbus specification |
Data Formats (selectable) | 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 | |
Main Board Revision Level | Level 5 or above |
Custom ASCII Protocol | |
Standards Compliance | Laurel proprietary protocol |
Data Format | No parity, 8 data bits, 1 stop bit |
Protocol Type | Text string based command mode or continuous data streaming mode |
Data Streaming Mode | User selectable for up to 60 readings/sec |
Main Board Revision Level | Any |