ameyzingg

Looking for better way to copy array into individual tags

6 posts in this topic

I am copying some data from a vendor PLC through MSG instruction into my PLC through CIP data table read. Is there a better way to break down this array of data into individual real tags through an instruction (something similar to WORD_to_BIT instruction in Modicon). I was looking at FAL instruction but its not exactly doing what I am looking for. Any help is greatly appreciated.

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If you're working with Logix5000 Platform then you can do something like the following:

In your PLC you currently have Vendor_Real_Array[0] through Vendor_Real_Array[100].

You can create a tag of type Alias called TempAmbientReal which is an alias of Vendor_Array_Real[0].  Then create an alias with a meaningful name for each of the 100 reals.

Before you say that sounds like a lit of work, don't forget once you've made the first couple you can export tags to excel.  add the rest and re-import.

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I just tried it and its working great, thank you! I want to branch out from this to one more question. How does the messaging works for UDTs in vendor PLC? 

For e.g. in a usual MSG instruction Vendor_Real_Array[0] is copied to Plant_Real_Array[0]

Where would Vendor_Real_Array[0].Volts will be copied to, if I don't have the same UDT in my PLC?

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OK now you're starting to mix references and confuse me.  

A MSG with a source of Vendor_UDT_Array in Vendor_PLC would need an identical UDT array in the Plant PLC to not error.

Are you moving an Array of UDT or an Array of Reals?

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Sorry for the confusion. I am moving both actually, with multiple MSG instructions. I am comfortable with array of reals since I have done those before. I am just not sure about UDTs.

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OK that's what I was thinking, but was wanting confirmation.  So let's assume you have a simple UDT for Vendor_UDT Type defined as Follows:

Vendor_UDT.Used is a Bool

Vendor_UDT.Value is a REAL

Vendor_UDT.Name is a STRING

Vendor_UDT_Array is an Array of type Vendor_UDT and a count of 16 for example.

You'll need a UDT Type in your PLC defined to match the Vendor_UDT type and you'll need an array that matches or exceeds the size of the Vendor_UDT_Array.

You'll right your message just like the REAL one only source and destination will be element [0] of the UDTArray.

You'll then be able to alias to each sub-element of the array just like you aliased to Real Array elements.

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