High-Speed Ethernet Board with USB, P/N LNET1

LNET1 is a second generation communications board that plugs into the middle slot of a Laureate 1/8 DIN digital panel meter, counter or timer. It provides a high-speed Ethernet port to connect the host instrument to a local area network (LAN), plus a USB port for programming or data output to a PC or HMI. High data rates are a major advantage compared to Laurel's first-generation LNET communication boards. The LNET1 board is normally ordered by selecting "A" as the communication option of a configured instrument.

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. Data rates can be 10 or 100 Mbits/sec depending on the router. Using Ethernet and Modbus TCP, the LNET1 board can be polled every 2 msec. Multiple instruments, each with their own assigned IP address, can be individually addressed and polled.

A mini-USB connector is standard and can be used for meter programming or for data polling as a Modbus slave at 38400 baud independently of polling via Ethernet. To connect to the USB port of a PC, use our cable CBL07 or another readily available A-male to Mini-B USB cable.

Cached operation is a key feature of the LNET1 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 USB communications and Modbus RTU/TCP commands. These are documented in our LNET1 & LNET1-485 user manual. 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.

Communications setup uses our free Laurel Network Setup (LNS) utility. That software automatically discovers the board's Ethernet IP address assigned by the WiFi router, the COM port used for USB communications, the meter type, and the signal conditioner type. It also allows the IP address to be assigned by the user. The USB port can be used with our free Instrument Setup (IS) software to set up all operating parameters of host instrument and remote instruments on an attached RS485 bus.