[foxboro] Locking / Disabling equipment

We're wrestling with the best way to lockout equipment operated by the DCS.
Our policy states that the technician doing the work must ultimately be in
sole control of the locking "device".  The obvious (and advertised) method
to prevent operation of a DCS-controlled device is via the block DISABLE
parameter.  However, anyone with access to SELECT (or any other way to get
block default display) also has access to the DISABLE parameter.  Our past
practice has been to physically lock a motor starter, disconnect a valve
air supply, remove a valve acruator, etc, rather than rely on the DCS for a
secure lockout.

I'd like to know how other users manage lock/tag/try for DCS-controlled
equipment.

Brad Wilson
ExxonMobil Chemical Co
Edison Synthetics Plant
732-321-6115
732-321-6177 fax
Brad.S.Wilson@xxxxxxxxxxxxxx

 
 
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