Chapter 3 Easy Programming Makes Better Project
Issue Time:2017-06-17


SETP_Ⅴ、Programming Optimization——Reducing the PLC operation load

Scan period of PLC plays a crucial role in programming operation, which makes sense in the application that requires higher respond. It is a common sense that the more steps of PLC programming needs, the longer time for scan period, as a result that optimization is needed.

The below program could be removed when performing device: basic date operation, manual operation, upload and download of recipe.

Take an example of E-cam program. The program owns 2099 steps but only 242 steps are performed, the scan period is 0.2ms-0.5ms.

图片2

图片3-3-3

How to optimize: parameter of M8002 should be programmed in subroutine as power-up initializing because it is only performed once.

图片4-4-4

P0 Initialize

图片5-5-5

Screen 5 and screen 6 are mechanical and process parameters, they will not change when the device is running automatically.

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The screen register is D90. In other words, when in the fifth screen, the device is not running automatically, PLC will perform the operation of process parameters(electronic cam table).

图片9-9-9

When in the sixth screen, the device is not running automatically, PLC will perform the operation of mechanical parameters.

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图片11-11Before optimization, the scan period of PLC reaches 1.3ms~1.9ms because of large date of CAN table. But it will reduce to 0.3ms~0.5ms after optimization, which surely can decrease the operation load and improve the stability of equipment.


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