2 posts in this topic

Hello Everyone,

First time user, I am having a hard time understanding the code for programming the FX2N-4DA. Using their manuals that came with product. I wrote the examble into the plc and it was okay. I want to understand what I am doing, and why I use them. My question is there a manual with broken down examples?

Thank You 

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The only manuals I know of are the Mitsubishi manuals.  Based on your question and the device you mentioned, I will guess that you are asking about the TO and FROM instructions.  If that is the case, I will do my best to explain it.  It has been a while and I am doing this mostly from memory.  The info below is generic and not specific to the FX2N-4DA.  I do not have  a manual for that handy. 

Analog cards and other special function modules need to be set up then read from across the backplane of the PLC.  This is not an automatic function and is accomplished by using TO and FROM.  Whenever we want to send something to the card, we use TO and whenever we want to read from it, we need to use FROM.  The instructions work this way:

          TO or FROM  [module number] [head address number] [data to read or write] [number of words or devices to read/write]

Module number:  In plain English, if you have a special modules in your rack, they start with 0 and number all the way to 7 in the FX platform.  The first one is 0, the next to the right is 1, then 2, etc.  This number can be a decimal constant (k) or hexadecimal constant (h)

Head address number:  This is the register in the module that you are reading from or writing to.  This number can be a decimal constant (k) or hexadecimal constant (h)

Data to read or write:  This is the info you are sending to or reading from the head address number in the module.  This can be a constant (h or k) or it can be a memory location in the PLC (i.e. D100)

Number of words or devices to read/write:  This is a constant (h or k) that tells the controller how many items to read or write.


Hopefully I got this right and didn't confuse you more.

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