Custom UDT mapper with string

[patopat]

Hi, Could you provide a short example about how to write a string from the following Custom UDT ? I use a CompactLogix controller 5370 and string is defined as LEN - DINT, DATA - SINT[82].

    public class CustomTagPlcPlcMapper : PlcMapperBase<CustomTagPlc>, IPlcMapper<CustomTagPlc>
    {
        public override int? ElementSize => 4 + 86;

        public override CustomTagPlc Decode(Tag tag, int offset)
        {
            var DINT0 = tag.GetInt32(offset + 0);
            var STRING0 = tag.GetString(offset + 4);

            var customTag = new CustomTagPlc
            {
                Id= DINT0,
                Datetime = STRING0
            };

            return customTag;
        }

        public override void Encode(Tag tag, int offset, CustomTagPlc value)
        {
            tag.SetInt32(offset + 0, value.Id);
            tag.SetString(offset + 4, value.Datetime);
        }
    }

    public class CustomTagPlc
    {
        public int Id { get; set; }
        public string Datetime { get; set; }
    }

Regards, Pat

[timyhac]

The code before change might be useful: https://github.com/libplctag/libplctag.NET/commit/fc7c18b374a60590896180346e62d1906cfd070b#diff-73f7e73fbc97c01ccd0cadbd895bab88133cd4a602da23a91fa449d223af81b6L67.

Be careful that you're using the right encodings - it looks like we previously assumed ASCII encoding but make sure its appropriate to your application.

When developing the UDT martialling logic it can be useful to use the GetBuffer() method to access the entire buffer, and inspect it using a hexdump tool. I normally use hexed.it.

If you're looking to use the string configuration properties it might be possible to set them in the Encode/Decode functions.

[patopat]

@timyhac ,

Yes, very useful thank you.

[timyhac]

Thanks!