4 posts in this topic

Hai, I am doing program for Mitsubishi FX3U Series PLC i don't know some options in that can any one help me to sort out this.

1) I assigned the Address Y040 for one output, suppose during the machine running this output is in ON condition, if the plc power went Off and On again, the output should be in the same previous state. can we do this? How? 

2) If i switch OFF the PLC power and Switch ON again i want to switch ON one Input Contact, only for the first time. What is that one scan ON input Address?

Please reply fast if you know..

Edited by KCRP

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Stop making multiple posts asking the same question.  Wait for an answer.  Or get blocked from posting.

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Hello KCRP,

If you exchange your output Y040 for a retentive Marker (auxilery relay) you can use this marker in the next row to activate the output Y040. (see simple example below)

For example, in the FX1 and FX2 series the retentive auxilery relay range starts from M384 and higher to keep the state after power fail. To have a complete overview of the range check the manual from you FX3u PLC. I've attached a part of te manual so you can see the M range, Timer range and counter range that is retentive and saves the value in the EEPROM of the PLC.

Keep in mind that motors can start automatically without any warning if Y040 starts a motor. It can be a very dangerous situation!! I use this construction very often and always put a timer that acivates a sounder for 5 seconds to warn the operator that the machine will start up after the timer has expired and they can take their hands out of the machine in time or press the emergency stop before the output of the motor is activated.


|--| |----(M384)

  X0 (your start condtions for Y040)

|--| |--(Y040)

M384 (retentive M)

You can also use a SET M384/RST M384

Best regards,

Theo V.


Mitsu FX3u_Retentive M-T-C.JPG

Edited by Theo V

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Thank you..so much sir for your valuable reply. This website is very useful. i like it. i am just a beginner for this PLC field please help me if i ask some questions.Thanks.

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