While reconciling mismatches between channel properties in the wireless Reconcile I/O dialog, observe the following operational characteristics of autosensing:
HART specifications constrain the length of the Tag property to eight characters, the Description property to 16 characters, and the Long Tag property to 32 characters. If needed, space characters are used to pad property identifiers to their maximum lengths. DeltaV allows longer text strings to specify these properties in the Channel Properties dialog.
For the purpose of determining a mismatch, autosensing comparisons do not consider trailing spaces used to pad a property identifier to its maximum length. Autosensing comparisons consider only the first n number of characters, up to the maximum allowed for the device according to HART specifications.
Therefore, for example, if you specify a device tag in DeltaV as TT07_C01WEST and the Tag property reported by the device is TT07_C01, it will not be identified as a mismatch in the wireless Reconcile I/O dialog, because the first eight characters match. However, if you specify a device tag in DeltaV as TT07_C01WEST and the Tag property reported by the device is TT07, it will be identified as a mismatch in the wireless Reconcile I/O dialog.
In accordance with HART specifications, an uninitialized Tag, Description, or Long Tag channel property value for a device is filled with question marks (?), up to its maximum allowable length. DeltaV allows unspecified values in the Channel Properties dialog to contain an empty string.
If you elect to reconcile a Tag, Description, or Long Tag channel property in favor of an unspecified value from DeltaV, the device value for that property is set to a sequence of eight, 16, or 32 question marks (?), depending on its maximum allowable length according to HART specifications.
String formats from the ISO Latin-1 character set are supported for the Tag, Description, or Long Tag channel property value of a device. If the string used to specify a Tag, Description, or Long Tag channel property in DeltaV contains a character disallowed by HART specifications, you cannot reconcile this mismatch in favor of the value specified in DeltaV.