ENw.d[Ee] (Exponential Editing:  Engineering form)

  On input, EN performs the same as F format.

  On output, EN transfers the value of the corresponding I/O list
  element, rounded to "d" decimal digits and right-justified to an
  external field "w" characters long.  The real value is output in
  engineering notation, where the decimal exponent is divisible by 3
  and the absolute value of the significand is greater than or equal
  to 1 and less than 1000 (unless the output value is zero).

  "d" specifies the size of the fraction and "e" specifies the size
  of the exponent.  If the value does not fill the field, leading
  spaces are inserted; if the value is too large for the field, the
  entire field is filled with asterisks.

  The term "w" must be large enough to include all of the following:
  a minus sign (when necessary) or a plus sign (if SP editing is in
  effect), one to three digits, zero, a decimal point, "d" digits,
  and an exponent.

  Therefore, to accommodate all possible components of the standard
  form, the term "w" must be greater than or equal to "d"+9.

  The exponent field width ("e") is optional; if omitted, the default
  is value is 2.  If "e" is specified, the "w" should be greater than
  or equal to "d"+"e"+5.