Four Strange Facts About Rs485 Cable

Rs485 is low impedance balanced , so twisting the pair helps with noise immunity as well as reducing the attenuation effect of higher baud rates due to the parallel capacitance of the wires in the cable jacket over the long lengths. The device ships with an Ethernet RS-485 communication interface as well as a RS-485 to USB cable, which is said to be able to communicate with a PC using proprietary Windows based software (and driver, I think). Category 5 (Cat 5, Cat 5e, and Cat 6) cables are the most common Ethernet cables in use today. Most computers conform to IBM PC AT-compatible RS232 interfaces which use 9-pin D-Type connectors, rs485 cable consequently the PDQ Board brings out its serial ports to two female 9-pin D-Type connectors on the Docking Panel. These 9-pin standard DB-9 serial connectors are located on the back of the Docking Panel. RS485Init() configures PORTJ to ensure that bits 0 and 1 are outputs, and disables both RS485 transmitters, leaving the Serial1 and Serial2 RS485 channels in receive mode. Each of the two channels on the UART Wildcard can be configured for RS232, RS422, or RS485.

The UART Wildcard provides two simultaneous communications links, each configurable as RS232, RS485 or RS422. For this reason, frame-level cyclic redundancy checks are much more widely used for validating data from serial links, network connections and storage media. After looking at all your links, I do not believe there is an actual Ethernet interface at all. Is it necessary to do the ethernet cable splicing as indicated in the above link, or should I simply be able to use the provided USB cable? The default serial routines used to download programs to the operating system assume that full duplex communications are available, so you cannot use the RS485 protocol to program the controller. The twin consists of two conductors that are twisted together. The shielding may be braided (be formed by a mesh of thin conducting wires) or be a foil (consisting of a sheet of metal wound around the conductors): the two types are equivalent.

These distances I'm talking about are greater than 100 meters. Single master systems (many other communications schemes are available) offer a straight forward and simple means of avoiding "data collisions" in a typical 2-wire, half-duplex, multi-drop system. It controls the serial-to-parallel and parallel-to-serial conversion and performs all of the timing functions necessary for asynchronous serial communications. Also, several non-serial interrupts can stack up; if they have higher priority than the serial interrupts, they will be serviced before the Serial2 interrupt routine, and again a serial input or output bit may be lost. To make sure that your USB to RS-485 cable & the device RS-485 port are working, have you tried using them with a Windows PC and the manufacturer's s/w? But You stated you are going to install this at a commercial setting, so it always better to use the worst case environment situations, and use shielded cable. 3106A is what I typically use to wire balanced audio.

Now there was certain instances I used STP wire for rs485 because I had a lot of devices connected in a long run chain (DMX512 lighting fixtures). It seems if there is a lot of RFI in the installation, shielded twisted cable can be justified. After the slave transmission is complete, the slave puts itself back into receive mode so that the master can transmit additional commands. A single master can broadcast commands to all the slaves, and can direct commands to an individual slave using its unique address. Simply using the provided USB converter cable is not working for me right now with the Pi. But I notice that he describes using a (different) RS-485 to USB converter and splicing from the Ethernet cable to the converter, rather than using the converter cable that ships with the charge controller. Note that this Hackster project does something similar with splicing an ethernet cable to a UART breakout module.