RS485 Interface Board for Micron MM50 Series Electronics 1/8 DIN Instruments

Key Features

• Includes dual RJ11 connectors for daisy chaining of meters without a hub.
• Allows up to 31 meters to be addressed using the Micron ASCII protocol.
• Allows up to 247 meters to be addressed using the Modbus protocol.
• Selectable full-duplex or half-duplex operation.
• Suitable for all 1/8 DIN Micron DPMs, counters, timers & remote displays.
• Selectable baud rates to 19,200.
• Isolated from meter and power grounds.
• Ideal for use with Micron's Ethernet-to-RS485 converter and USB-to-RS485 converter boards.

Description

The Micron RS485 interface board allows multiple Micron meters, counters, timers and remote displays to be connected to the same RS485 line. Dual RJ11 jacks allow multiple devices to be daisy-chained using readily available 6-wire data cables or patch cords with RJ11 plugs (P/N CBL03). Also, in the absence of a computer, a single Micron meter with an RS485 board can drive multiple Micron 6-digit remote displays.

Ideal complements to the RS485 interface board are Micron's Ethernet-to-RS485 converter board, which connects a meter network to an Ethernet LAN, and the USB-to-RS485 converter board, which connects a meter network to a host PC via a standard USB cable. Both converter boards provide an RJ11 interface to an RS485 network, which can consist of multiple Micron meters that are easily daisy-chained via readily available 6-wire data cables.

Operation can be configured for full-duplex or half-duplex operation using jumpers on the RS485 board. Transmission distances up to one mile are possible. In case of long line lengths, a jumper can be plugged in the RS485 board at the end of the line to insert a 120-ohm termination resistor to minimize signal reflections.

Three serial protocols are user-selectable: Modbus RTU, Modbus ASCII, and Micron ASCII. For more information, please see our Modbus Protocol Serial Communications Manual and our Serial Communications Manual.

• The Modbus protocol is an international standard and allows Microns to share the same RS485 data lines with non-Micron devices. It supports up to 247 digital addresses. Use of more than 31 Micron RS485 Modbus boards requires repeaters for impedance reasons.
• The Micron ASCII protocol is the simplest and is recommended if the only devices on the RS485 data line are Micron meters. It supports up to 31 digital addresses.

The Micron RS485 interface board is similar to the RS485 interface board, except that it features dual RJ45 connectors instead of RJ11 connectors. While use of RJ45 connectors is recommended in the Modbus standard, RJ11 connectors are also popular, and both of our RS485 boards support the Modbus communications equally.

The Micron RS485 interface board provides two 6-pin RJ11 jacks, whose pins are wired in parallel. This allows multiple Microns to be daisy-chained using readily available 6-wire data cables with no need for an RS485 hub. The resulting RS485 network can be connected to a LAN via Micron's Ethernet-to-RS485 converters, or to a host PC via Micron's USB-to-RS458 converter.

The signal levels of the Micron RS485 board 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.