The Rs485 Cable Chronicles > 자유게시판

When a single RS485 meter or counter is connected to a PC via a cable CBL06, set the PC to 9600 baud. See page 7 of the Laurel digital panel meter manual, page 7 of the Laurel counter manual, page 8 of the Laurel scale meter manual, or page 8 of the Custom ASCII protocol manual. A single analog input meter or transmitter can stream readings to a PC at up to 60 readings per second and the Custom ASCII protocol set to continuous (or streaming) model. RS485 is simpler because it uses only two wire (or a single pair) to carry out the data in bidirectional manner, using RS232, we need 3 wires at minimum to carry the data bidirectionally. Laureate meter and LT series transmitters support the Modbus RTU protocol and Laurel’s simpler ASCII character based Custom ASCII protocol. Use Laurel’s 6-wire data cables CBL03-1 (1 ft) and CBL03-7 (7 ft) to interconnect meters if these lengths fit your application. The data COM port on the base of the Solis inverter uses a small round 4-pin plug with a screw thread to hold it in place when connected. The solution is provided by the Laureate DIN rail mounted breakout board, which provides two RJ11 jacks with six screw clamp terminals all wired in parallel.

The two jacks are for RS485 cable in and RS485 cable out. These cables allow the dual RJ11 jacks of the RS485 option board of Laureate meters (digital interface ordering option 2) to be daisy chained and to be addressed digitally with no need for a hub. RS485 is in its design a different interface from RS232. 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). You can easily connect more devices by splitting the cable at one connector and adding another cable to it. This cable provides a USB type A connector for the PC end and an RJ11 connector for the meter end. 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. 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.

Two wire telephone cables will not function because in that case the ground signal levels on both sides will be floating. In this case it is possible to connect the main inlet and outlet terminal directly to the terminals of an instrument without creating a branch. The model R485i opto-isolated repeater solves these problems by creating a second network electrically isolated from the first. Test options include: audio, video, ping, TDR, PoE, IP network connections, and LAN (local area network) cable connections. The cable shield must be earthed only in one point. If we want to connect a PC with an Unitronics PLC, for example for programming or debugging reasons, we need a connection cable which is on one side fitted with a female DB9 connector, and on the other side with an RJ11 jack. Not more than one breakout board is required per RS485 line. The existence of an RS485 port on the socket makes it even a little bit more difficult. 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. Using the Solis Data Logging Stick, which uses WiFi to communicate, we were able to set up the inverter to send data to the remote soliscloud service, but we could not find any way to get capture data apart from scraping the basic status page built into the WiFi adapter which only gave watts being produced and daily output.

Our plans to upgrade our solar PV system this year are slowly progressing with installing a new Solis 1.5kW inverter and an EM112 Series Energy Meter, which have RS485 output and communicate using Modbus protocol. The RS485 system used for Modbus communication provides a main cable (Bus or backbone), to which all the devices have to be connected with branches (also known as stubs) that are as short as possible. Figure 1 shows an example of a correct Bus connection. The diagram below shows a basic RS485 cable for use with the RJ11 socket on Unitronics PLCs. It shouldn’t however be a surprise that the pin assignment on the RJ11 socket on Unitronics PLCs is different from the two systems mentioned above. The RJ11 socket in the Unitronics PLCs provides six signal pins. These pins have to be connected to handshaking outputs at the PC side on the RS232 port.