Features
- Fits all Laureate 1/8 DIN size meters, counters and timers
- High-speed RJ45 Ethernet port for data
- High-speed RJ11 RS485 port for setup or data
- Can act as an Ethernet-to-RS485 gateway to an RS485 bus with up to 31 Laureate meters or transmitters
- Allows host and remote instruments to be polled using Modbus commands
- Network speeds of 10 or 100 Mbits/sec
- RS485 speeds up to 115200 baud
- Updated analog readings every 18 msec
- Updated counter readings every 11 msec
- Isolated from meter and power grounds
Certificates of Compliance
LNET1485 is a second generation communications board that plugs into the middle slot of a Laureate host 1/8 DIN digital panel meter, counter or timer. It provides high-speed Ethernet and RS485 ports to connect the host instrument to an external local area network (LAN) while also serving as an Ethernet-to-RS485 gateway to an RS485 bus with with up to 31 Laureate meters or LT series transmitters. High data rates are a major advantage compared to Laurel's first-generation communication boards, which include the legacy LNET485 board.
Ethernet operation complies with IEEE 802.3 and utilizes an industry-standard RJ45 jack for a 10/100 Base-T connection to a local area network (LAN) or directly to a PC or HMI. Multiple instruments, each with their own assigned IP address, can be individually addressed using the Modbus TCP protocol. Internet WAN connectivity is supported so that instruments can be set up and read over the Internet. Data rates can be 10 or 100 Mbits/sec depending on the router. Using Ethernet, cache of the LNET1485 board can be polled via Modbus TCP every 2 msec.
An RJ11 connector is standard for RS485 and can be used for meter programming, for data polling as a Modbus slave at up to 115200 baud, or for operation as a Modbus master at 19200 baud to an RS485 bus with up to 31 addressable Laureate meters or LT series transmitters. Meters on the RS485 bus can be daisy chained using our CBL03 data cables. LT transmitters can be added using our BKBD breakout board.
Use of cache memory is a key feature of the LNET1485 board. It allows the host meter to be polled at the maximum rate allowed by the meter's main board, and in turn to be polled asynchronously at a much faster rate using external Ethernet or RS485 communications with Modbus RTU/TCP commands. These are documented in our user manual for Gen 2 Laureate communication boards. Updated analog readings can be retrieved every 17 or 20 msec, depending on the meter's 60 Hz or 50 Hz AC line noise rejection setting. Cashed counter readings can be retrieved every 10 msec.
Setup of Ethernet and RS485 communications uses our free Laurel Network Setup (LNS) utility running on a PC. That software automatically discovers the board's IP address assigned by the network router, the COM port used for RS485 communications, the meter type, and the signal conditioner type. Our CBL06 RS485-to-USB adapter cable and CBL08 RS485 splitter cable are required to connect the board's RJ11 port simultaneously to the USB port of a PC an to the external RS485 bus. The board's RS485 port can then be used to be used to set up the host instrument and instruments on the RS485 bus using Laurel's free Instrument Setup (IS) software in lieu of front panel programming.
Basic Ethernet Operation
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Ethernet-to-RS485 Gateway Operation
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| Ethernet Operation | |
|---|---|
| Ethernet standard | IEEE 802.3 |
| Ethernet connector | RJ45 jack |
| Ethernet cable | 10/100 Base-T |
| Data rate | 10 or 100 Mbits/sec |
| Communications protocol | Modbus TCP (same commands as Modbus RTU) |
| Min read interval from cache | 2 msec |
| RS485 Operation as Slave to a PC Master | |
| RS485 connector | RJ11 |
| RS485 cables | CBL06 cable to PC USB port |
| Data rate | 9600, 19200, 38400, 1152000 baud |
| Communications protocol | Modbus RTU (same commands as Modbus TCP) |
| Min read interval from cache | 5 msec |
| COM port | Discovered by Laurel Network Setup (NS) utility |
| Ethernet-to-RS485 Gateway Operation as a Master to an RS485 Bus | |
| Connector to Ethernet | RJ45 |
| Connector to RS485 bus | RJ11 |
| Cables to meter | CBL06 cable to PC USB port plus CBL08 RS485 splitter cable to RS485 bus |
| Cables for RS485 bus | CBL03 non-reversing data cables for daisy chaining |
| Data rate on RS485 bus | 19200 baud |
| Communications protocol | Modbus RTU (same commands as Modbus TCP) |
| Time to service DPMs | 17 msec or 20 msec (filtering set for 60 Hz or 50 Hz) x number of meters on RS485 bus |
| Time to service counters | 11 msec x number of counters on RS485 bus |
| Provision to add transmitters | BKBD breakout board |
| Cache Memory | |
| Data written into cache | Display value or set of 6 values (user selectable) |
| 6 values for analog in DPMs | Alarm status, display value, peak, valley, display value, display value |
| 6 values for scale meters | Alarm status, display value, peak, net weight, gross weight, display value |
| 6 values for counters | Alarm status, item 1 (display value), peak, valley, item 2, item 3 |
| Write interval for 1 value | 16.666 msec or 20.000 msec (filtering set for 60 Hz or 50 Hz noise rejection) |
| Write interval for 6 values | 100 msec or 120 msec (filtering set for 60 Hz or 50 Hz noise rejection) |
| Read inteval from cache | Set by externa Modbus Master, 2 msec min for Ethernet, 10 msec min for USB |
| Measurement Update Intervals | |
| Analog input meter | 18 msec or 21 msec (filtering set for 60 Hz or 50 Hz noise rejection) |
| Totalized pulse readings | Signal period or programmable gate time from 10 msec to 199.99 sec |
| Frequency/rate readings | Gate time + 30 msec + 1-2 signal periods |
| Communication Protocols | |
| Data I/O via Ethernet | Modbus TCP/IP (same command set as Modbus RTU) |
| Meter polling via RS485 | Modbus RTU |
| Meter programming | Front panel keypad or Instrument Setup (IS) software |
| Mechanical | |
| Board dimensions | 79 x 39 mm |
| Mounting location | Middle slot of Laureate Series 2 panel meter or counter |
| Environmental | |
| Operating temperature | -40°C to 85°C |
| Relative humidity | 95% from 0°C to 85°C, non-condensing |
| Electrical Protection | |
| 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 1000-4-4 |
| Short circuit protection | Continuous |
