Limit alphanumeric characters for a field? Custom Expression?

[martino1]

I want to limit characters for different fields.  I tried doing a combination of text and alphanumeric string validations, but it wouldn't validate correctly when testing the form if I added spaces between words, so now I am trying to do it with a custom expression, but that isn't working either.  I saw something similiar to the syntax below on another post, but it isn't working for me.  The format below is what I am using.  What am I doing wrong? Also, do I need to add 'signer1', 'signer2', or 'anyone' to validate the signer or does that take care of itself by who I assign the field to in the options box? Lastly, do I need to change the syntax below for text string vs alphanumeric string?

{{fieldname_es_:string(maxlen=30)}}

[martino1 · Accepted solution]

So this was a simple solution.  I am providing a screenshot for anyone who has this question.

 

[Shield Nation27900928rp7p]

Is the dollar sign required?  If I just want a character max is that the text needed to make this work?  Does anyone know how to have a character minimum and maximum to ensure the number of digits collected is correct?  for example, routing numbers must be 9 digits.