PLC | RS485 Mode: ASCII vs RTU

RS485 communication, there are two different formats to choose from.
In addition to different formats, you know that also affect those who do!?

ASCII format:
Start code +7-8 bit data + parity + end code
data = ASCII code (0-127)

RTU format:
Start code +8 bit data + parity + end code
data = 16 hexadecimal code (0-9, a-f)


Points of difference:
1.ASCII can express the words, RTU not.
2.RUT one can send two numbers, ASCII can only send one.
3. Check for errors in different ways.
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In PLC communications with external devices, the
There will only be numbers, there will be no the text communication,
RTU can speed up the selected so the speed of the handshake.

PLC|RS485模式選擇: ASCII vs RTU

RS485通訊中，有兩個不同的格式可以選擇。

除了格式不同，你知道還影響到那些嗎!?

ASCII 格式：

開頭碼+7-8bit data+同位元+結束碼

data=ASCII code(0-127)

RTU格式：

開頭碼+8bit data+同位元+結束碼

data=16進制碼(0-9,a-f)

差異點：

1.ASCII 可以表達文字，RTU不行。

2.RUT一次可以發送兩個數字，ASCII只能發送一個。

3.檢查錯誤方式不同。

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以PLC跟外部裝置通訊來說，

只會有數字，不會有文字的溝通，

所以選RTU可以加快交握的速度。

PLC | RS485 to use HMI communication is the best choice

In the last article written, because the relationship between the PLC scan time,
Makes the communication time <scan time,
A lot of time wasted on the PLC scan time.

The HMI is to use the firmware to handle the communication, to avoid the problem out of the PLC scan time.

If you use the HMI to do RS485, another relative problem will occur.
1 HMI communication with the PLC's different way of writing.
2.PLC, HMI & control of both sides of the program, follow-up would be more trouble Debug.
3 HMI will usually far away from the other components, interference issues to consider.