For master configuration choose "Master" as type and input the addresses of the slaves in the RS485 bus as a comma separated list. The presence of a new board and the type of board are automatically sensed by the meter’s firmware or by Instrument Setup (IS) software. RS485 uses two wires and sometimes a ground connection, so we used a twin-screen cable to go between the inverter to the EM112 Series Energy Meter and then onto the Raspberry Pi with a DB9 connector connected to the RS485 Pi board. To minimise shadows over the top row of panels, we decided to mount 2 on the top row and 3 below, which will give us a theoretical maximum output of 1.6kW, which is suitable for the Solis Solar 1.5kW Mini 5G Inverter. Xwire protocol over RS485 will allow cable runs of up to 1km - with suitable cable and grounding precautions- and up to 32 devices. Henceforth, we shall consider Slave devices to be measuring instruments with serial communication, even if the cabling is similar for all Modbus devices.

Configure the extension as slave or master (as described here). Where should I go from here? I inserted a metal piece in the middle pin of the cable (the TX) and I could see garbage data showing on the screen (sometimes!). Another thing I've done is connecting the slave device to to the SENA RS485 adapter, and use the metal piece on the pins, the middle pin of the adapter, when touching the metal, makes the TX led turn on. This module is powered by the RS232 port from the connecting computer. RX led. When connecting that RS485 adapter to the PC's COM port, sending data to that port would make the RX led flash. By using two jacks, rs485 cable up to 31 L485 boards can be connected in parallel for daisy chaining using readily available CBL03 data cables with no need for a hub. Laureate RS485 boards are available in versions with dual RJ11 jacks (ordering option 2, board P/N L485) and with dual RJ485 jacks (ordering option 4, board P/N LMOD). Bus Probes can be configured and tested using our web-based test app (you will need to connect the probes to your PC or Android smartphone via our Web485 board).

If the bus is only a few meters long then the cable you use should not matter. The older RS232 standard uses single-ended signals, is more sensitive to noise, and is only rated for distances up to 50 ft (15 meters). This provides high noise immunity and allows distances up to 4,000 ft (1200 meters). The MEV RS485 Repeater allows communication between RS485 systems in otherwise impossible situations. In theatre and performance venues, RS-485 networks are used to control lighting and other systems using the DMX512 protocol. Both boards support the Modbus protocol and Laurel’s Custom ASCII protocol, as well as half-duplex or full-duplex RS485 communications. If multiple analog input meters or transmitters are digitally addressed in command mode on an RS485 line using the Modbus RTU protocol or the Custom ASCII protocol, the rate becomes about 2 readings per second. What cable should I use to connect meters with an RS485 port to the USB port of a PC?

Without termination resistors, signal reflections off the unterminated end of the cable can cause data corruption. I plugged the male-male adapter to the cable and touched the middle pin again, and I could see garbage data again. The main difference is, that pin 1 and 6 on the RJ11 socket of the MJ20-PRG module are used as power supply. The Master Brick of each stack has to be the lowermost Brick (except if you are using a Power Supply). To create a RS485 bus, stack the RS485 Extension on top of a Master Brick. You should see the Master Brick view with the identified RS485 Extension (see images below). You should now be able to see all connected stacks in the Brick Viewer. To set up communications for your meter or counter, see the Serial Communications section of its user manual. RS485 is the preferred serial communications standard for long distance industrial communications. This MJ20-PRG module clicks in the PLC and provides one RJ11 socket for serial communications with a PC. Due to loading limitations one of the best uses of a RS232 to RS422 serial converter might be in point-to-point communications, such as extending an existing RS232 line.