As simple as it may seem, instrumentation documentation is not always implemented into the scope of a project. At the beginning of every project, big or small, instrumentation documentation should always be included as a deliverable. An instrument data sheet is a detailed document that contains process data, operating conditions and instrument specific data. Not only is a data sheet important because of the data it holds but it also provides a paper trail and proves someone did their due diligence in selecting the correct instrument.
An instrument index is a document containing a list of devices withing a facility. The instrument index will contain a tag number for all physical instruments as well as "soft tags". The instrument index can include not only off skid instruments but all on skid instruments as well. An instrument index shall be created at the beginning of project and considered as a live document which should be kept updated even though the plant has been constructed and operated. The instrument index shall be revised if there is any plant or system modification which impact to additional, removal, or resetting of an instrument. Specifically, the instrument index must include but is not limited to: Facility LSD, Instrument Tag, Instrument Identifier, Instrument Type, Service Description, Equipment or Line Number, PID Number, Manufacturer, Model, IO Type, Signal Type, Power Supply, IO Address, Operating Range, Calibration Range, Setpoint, Alarms and Shutdowns.
A facility I/O Worksheet is another document used when sizing an RTU, PLC or DCS. This document will help organize and categorize the devices found in each area or building. Electrical and Instrument devices will be categorized as either Discrete Input, Discrete Output, Analog Input, Analog Output or Communication. For an older installation, the plant documentation may only exist as a series of paper documents. Today the documentation created for a new or upgraded facility is produced electronically using manual entry spreadsheets or automated design tools and software.
Almost all facilities from the past and new state of the art facilities still use pneumatic instruments for various control loops. A correctly sized instrument air compressor unit will greatly improve reliablity and operation of pneumatic instruments. An instrument air compressor sizing spreadsheet is a useful tool used to quantify the estimated air consumption of a facilities pneumatic devices. This allows for properly sized compressors, filters, wet/dry air receivers and driers.
Nagy Instrumentation & Controls Inc. can provide all necessary documentation and templates.