User key

Quote from Mangesh Shenavi

Hello all.

I am using KR300R2700 - 2F / FLR

With KRC 4 Controller

Application - Pick & Place. (Material Handling)

First i am using separate user keys for gripper open & gripper close. I am using this keys as

In SPS.

IF Is_Key_Pressed(14) THEN

Gripper Open pulse.

ENDIF

IF Is_Key_Pressed(15) THEN

Gripper Close pulse.

ENDIF

I want to open & close gripper on same (single) button.

As like, if gripper is open then it will be close & if gripper is close then it will be open.

I think, setting a flag is better option, but please suggest best way to use a single button.

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Hello;

First of all, you should have sensors that see the open and closed position of the gripper. your sample program should be like this;

$IN[1] : Your Gripper Open/Close Button/Command

$IN[2] : Gripper Opened

$IN[3] : Gripper Closed

$OUT[1] : Gripper Open, Output *

$OUT[2] : Gripper Close, Output *

IF ($IN[1]==TRUE) THEN

IF ($IN[2]==TRUE) THEN

$OUT[2]=FALSE; *

WAIT 0.1;

$OUT[1]=TRUE; *

ELSEIF ($IN[3]==TRUE) THEN

$OUT[1]=FALSE; *

WAIT 0.1;

$OUT[2]=TRUE; *

ENDIF

ENDIF

* if your valve is permanent type, not spring return PULSE can be used. Etc;

IF ($IN[1]==TRUE) THEN

IF ($IN[2]==TRUE) THEN

PULSE($OUT[1],TRUE,0.5)

ELSEIF ($IN[3]==TRUE) THEN

PULSE($OUT[2],TRUE,0.5)

ENDIF

ENDIF

Quote from Mangesh Shenavi

I want to open & close gripper on same (single) button.

You'll need some sort of memory latch to create an edge-trigger on the button.

DECL BOOL bButtonMemory

; inside the USER_INIT portion of SPS
bButtonMemory=FALSE ; init value before use

; inside the USER_PLC portion of SPS
IF IsKeyPressed(KeyNumber) AND NOT bButtonMemory THEN
  GripperOpenOutput = NOT GripperOpenOutput ; invert output
  GripperCloseOutput = NOT GripperCloseOutput ; invert output
ENDIF
bButtonMemory = IsKeyPressed(KeyNumber)

This should flip the True/False states of both outputs when the button is pressed, but not keep flipping them every SPS loop if someone hold the button down. The idea of the memory BOOL is to make the IF statement only trigger once, when someone presses the button. Then it cannot trigger again until the button is released, then pressed again.

you cannot get input activated by pressing status key. at least not directly because inputs are read-only.

you could write code that activates output... the output could be wired to input (or echoed back in a PLC for example...)... then you have input that corresponds to status key state

yes all variables need to be declared before use. where and how you declare and initialize them will have impact on life and scope of the given variable.