With this boards, a CBL03 lines with RJ11 connectors can branch out to support an RS485 line consisting of three discrete wires. If you change boards, also change the model number on the meter label. Using a repeater, the main cable is divided into different segments, each of which can be up to 700 m in length and connect 32 devices (this number includes the repeaters). The maximum number of repeaters that should be serially connected is 3. A higher number introduces excessive delays in the communication system. The maximum number of devices that can be connected to a main cable is 32, including the Master. The diagram below shows a basic RS485 cable for use with the RJ11 socket on Unitronics PLCs. With the RS485 Pi connected to the energy meter, we could read the data but not from the inverter. Is there an easy way to log data to a PC from multiple instruments on an RS485 bus? We tried several RS485 Pi hats, but all had the same issue.

After several frustrating days of trying different combinations of RS485 hats, different wiring connections, with and without termination resistors and ordering a USB RS485 adapter which would also fail to connect, we tried to install the Data logging WiFi adapter. A Modbus RS485 connects a Master device to one or more Slave devices. This adaptor connects to the Xwire port on any SPLat controller and converts it to an RS485 interface. Wire up the RS485 stacks and set the termination switch on the first and last RS485 Extension in the bus to "on", as shown below. If you want to use a stack with RS485 Extension in your existing Modbus network, you have to match the values with the other bus participants. To configure a RS485 Extension you first have to choose the baud rate, parity and stop bits. Following being scammed by the Zero Home Bills solar panel supplier, we placed an order with another supplier whose website showed that they had the panels we required in stock, but after a few days, they contacted me to say they did not have them, and the website hadn't been updated for a long time. Then use front panel programming to set the baud rate, protocol, digital address, half or full duplex, and other available parameters.

In all other cases, half duplex and full duplex will work equally well. A meter will a thermocouple input and set for Modbus RTU needs to set to full duplex even if the wiring and the receiving unit are for half duplex. The Master Brick of each stack has to be the lowermost Brick (except if you are using a Power Supply). If you want to change something in your bus, e.g. add new Bricks or Bricklets, you have to power down the stack you would like to change, change it and repower it. If you restart the RS485 Slave, only the Bricks/Bricklets that are connected to this stack will send the initial enumeration message again. If you restart the RS485 Master, every Brick/Bricklet of the RS485 network will send the initial enumeration message again. Therefore for RS485 communications no crossover cable is used. We also highly recommend using paired twisted cable for connecting most converters. RX led. When connecting that RS485 adapter to the PC's COM port, sending data to that port would make the RX led flash.

Removing the WiFi adapter and connecting directly to the inverter's COM port resulted in no data again so we knew that there was something on the WiFi adapter enabling the data from the inverter. What cable should I use to connect meters with an RS485 port to the USB port of a PC? 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!). You should now be able to see all connected stacks in the Brick Viewer. I plugged the male-male adapter to the cable and touched the middle pin again, and I could see garbage data again. Otherwise a full 6 wire cable must be used. This distance does not include the branches (which must nevertheless be short). The branches must be no longer than 1200 m! This provides high noise immunity and allows distances up to 4,000 ft (1200 meters). The RS485 interface allows the creation of multi-point networks. Sometimes it is necessary to transmit over longer distances, or to run networks with spurs off the main cable run. For RS232 a crossover cable is used where pin 1 is connected with pin 6 at the other connector, pin 2 with pin 5, etc. This interconnects the transmit and receive signals of both PLCs, and also the handshaking signals DTR and DSR.