The error generated by the PLC scan

The error generated by the PLC scan
To decide everything in the digital era, all of the CPU clock.
Still have to go through the CPU computing, and then output the results.


A relatively simple

- | X0 | ------- (Y0) -
X0 trigger Y0 output.
General requirements, we know that it is immediately output.
If high-speed machines, in fact, has been delayed for a scan time of about (10 ~ 20ms).

The output contacts are usually the end of the scan will be output.



For example:
Machine speed of 80 m / min, 10ms difference of about 13mm.

General photoelectric sensors, sensor response time, about ns level.

PLC 誤差計算

在數位的時代，一切都是CPU的時脈來決定一切，
所以沒有所謂的立刻，還是要經過CPU的運算，再輸出結果。

再簡單不過的

-|X0|-------(Y0)-
X0觸發Y0輸出。
如果是一般的要求，就知道是立即輸出。
如果是高速的機構，其實已經DELAY了1個掃描時間約(10~20ms)。

因為輸出接點通常是在掃描結尾才會輸出。



假設：機構速度80米/分鐘，10ms已經差了13mm左右。

一般光電感應器的sensor也是有反應時間，約 ns級。


如果機台沒需求這麼高，就不要為難自已，無視這些誤差吧!!

High-power protection circuit for PLC

All transistor outputs of DVP-ES2/EX2 series PLC contain diode for back EMF protection, which is sufficient for small-power conductive load and average ON/OFF application frequency.
However, in big-power or high ON/OFF frequency environments, please connect to another suppression circuit (as shown in the figure below) to lower the noise and prevent damages on the transistor output circuit resulting from over-voltage or overheating.

The transistor outputs are all open collector; therefore, if Y0/Y1 is set to be pulse output and to ensure the transistor module works normally, the pull-up resistor has to be maintained at output current > 0.1A.
Circuit wiring for transistor output:

information sources:DELTA