485 communication issues

The theoretical distance is 1200 meters. How much data do you want to transmit? That’s about it; it’s more than enough for your needs!

If high real-time performance is required, 485 is not recommended, regardless of the number of measurement points.

①When writing programs for digital inputs/outputs (referring to low-level PLCs and other programmable devices), it is best to store them within one byte; this way, when the upper-level DCS reads them, it can retrieve 8 values at once through a single communication process. It can save communication resources. ②Do not pursue zero latency to an extreme extent, as the DCS controller has to perform other tasks in addition to monitoring this lower-level PLC. Think about it – is it worth investing most of your effort in communication tasks? Moreover, the basic loop scanning time when connected to your DCS is only 1 or 2 seconds. There is no need to require corresponding latency-free operation for the lower-level device. ③Distance is related to the transmission baud rate. There is no clear and direct relationship with the size of the data transmitted. Then I’ll provide you with a basic calculation formula: you can give it a try. But it's better to have a margin. Assume that the communication frequency is 9600 bps, meaning the communication rate is 9600 bits per second, which is equivalent to 9.6 bits per mS. A character generally contains 11 bit informations (start bit, stop bit, 7 or 8 data bits, parity bit). The time required to send or receive a character is approximately 1.145 mS. Source: http://www.ad.siemens.com.cn/club/bbs/post.aspx?a_id=1342411&b_id=64&s_id=83&num=18#anch

How talented Haiyou is. I’ve learned something. What communication method should be used for zero latency? Communications are not allowed to be integrated into the interlocking system… Both real-time performance and error rates are unreliable; don’t even think about it.

How much data can actually be transmitted? Experts, please calculate it