CoDeSys note 2: set coil and reset coil

Set coil

It can be understood as a self-locking coil , Imagine that the front contact is a key switch , When this switch is pressed , The coil is set to ture, Or it can be understood as 1, Coil pull , The contact state corresponding to the coil is reversed .

Then the front contact can no longer control it , How can I reset it ？

Reset coil

And the logic of the set coil is opposite , It can be understood here , Imagine there is a key switch in front （ characteristic ： When not pressed, the physical electrical circuit is connected , The line will disconnect when you press it ）, In the beginning , The whole line is connected , This coil （ Reset coil ） There is electricity , its The logic is 1, No output . If you press the switch at this time , The line is disconnected , Coil power loss , its Logic becomes 0, Have output . If you release the switch again at this time , The line is connected again , The coil is energized again , Logic changes again by 1, No output .

 

I understand it ：

1、 When the external normally closed button is not pressed ,i0.5 This normally closed contact is not triggered , This contact is conductive , Not connected here means that the contact is normal , There's no flip , It doesn't mean that the circuit is not connected , In this context, it means this , At this time, the rear reset coil is charged . This is the time ,q0.1 The coil is closed , Its value is 1, But it has no output .

2、 When the external normally closed button is pressed ,i0.5 Connect , The connection here refers to the change of the contact from normally closed contact to normally open contact , A flip has occurred , In fact, the physical circuit is cut off , The back coil loses power .

For this reset coil , After power loss, the state changes to 0, This is when the output begins , Output is 0, Its important function has worked ： Change the upper set coil into 0（ The setting coil has changed to 1 了 ） from 1 become 0 It's called reset , So it resets the setting coil . And the setting coil becomes 0 after , It will no longer output .

3、 This is the time , The external normally closed button is released , Not connected , In fact, there is electricity on the circuit of the reset coil , The reset coil remains disconnected in the previous step （ Non closing state ）.

Be careful , The reset coil at this time is completely different from the ordinary coil , At this time, the coil is energized , however , Its coil is not engaged （1）, Its coil is disconnected （0）. If it is an ordinary coil , When it is powered on, it immediately pulls in （1）, Disconnect immediately after power loss （0）.

The final effect ,q0.1 The final state is the output of the reset coil 0 Controls the , And the output of the set coil 1 invalid .

To sum up ：

Reset coil and set coil are not ordinary coils , It's important here , Don't simply think that their law is also the law of ordinary coils , Even if their power is turned into 1, Power loss turns into 0, Logic is 0 and 1.

Ordinary coil Output immediately after power on 1, Output as soon as power is lost 0, If the front call changes, it will change immediately

Set coil Output immediately after power on 1, After that, no matter whether there is electricity in front , Its output is 1

Reset coil Output immediately after power loss 0, At this time, you can clear the setting coil 0, After that, whether there is a click in front or not , Its output is 0, Until the setting coil turns it into 1

In fact, it can also be directly separated from physical devices , Understand directly with program software , Imagine as a register , Setting is to change this variable into data 1, Reset is to change this variable into data 0

Whether the coil has output ？

The output is 0 still 1？

These two questions are easy to confuse people , My understanding is as follows

They are all coils , Each has its own state of attraction and disconnection , Pull in as 1, Disconnect as 0, But they don't have to output their own state , But once they meet certain conditions, they start to output , that ：

When the setting coil has output , The output is 1

When the reset coil has output , The output is 0

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