# Create string HMI tags

String tags refer to ASCII strings or a series of characters or whole words.

When creating string HMI tags:

- You cannot define an alarm for a string tag.
- The initial value for a string tag must be less than or equal to its length.
- You must append the modifier "Lx" to the address, where x specifies the number of 16-bit words to read or write, instead of the number of bytes. Do not add any space between the address and the appended length modifier. If you import a legacy application, you will need to modify the addresses of any string tags unless they already use the string (ST) data type. For example, string displays, string input objects, and the alarm message connections may require the modification.
- In the Tags editor, in the Length text box, type a number (1-82) to specify the length of the string tag in bytes. The length must be a multiple of the size of the programmable controller data element you are addressing. For example, if you reference two-byte data elements in an integer section, the string tag length must be a multiple of two. If you reference one-byte data elements in an ASCII section, the string tag length must be a multiple of one.

  Tip: | String HMI string tags that use the Integer (N) and Binary (B) data types cannot be written to or read. Each graphic display can contain up to 1000 references to expressions or tags. When setting up a string tag that will read from a Logix 5000 processor, in the Tag Browser, select the element ending in .len. When the address appears in the Tags editor, delete .len from the address. If you are using ControlLogix® string tags with a non-zero index to the string array, the length you specify for the tag must consider the index value. In other words, when the array index "x" is greater than 0, the length of the string to be displayed will be 82 - x. If you do not make this correction, wire-framed values will be shown. In the first example string below, the index is 0, and the length of the string to be shown is specified as "sc82". In the second example string, the index is 9 and the length of the string to be displayed is adjusted accordingly: "sc(82-9)" `{[Control_Logix]ST1[10].DATA[0],sc82}` `{[Control_Logix]ST1[10].DATA[9],sc73}`

## See also

Create HMI tags

About data sources

Log tag data