An instrumentation list contains the final information about the tag, the purpose of the instrument, the type, the range and any other important information discussed on site. It should be simple and has to be kept actualized at all times.
FIGURE : P&ID for flasher level control
The content of the instrumentation list have an instrument index list with all the associated documentation, such as loop drawing number, datasheets, installation details and P&ID.
The other parts of the instrumentation list should describe the role of the device, tag number, specification and details of the model type and number.
The information developed and maintained for process control could reside in a computer and in a more flexible form called an instrument database. The instrument list and the instrument index are simply subsets of the instrument information available in the database.
Since most instrument signals are fed to a computer system, the instrument list and the inputs and outputs list (I/O list) may be combined into a single database to reduce data-entry overlap.
An example of an instrumentation list using the flasher level control example is shown in Table 1.
TABLE 1: Instrumentation list for a flasher level control
A general rule of thumb is that if something has to be purchased, mounted, wired or tubed, then it should appear in the instrument list.