{"id":40415,"date":"2019-02-24T12:20:51","date_gmt":"2019-02-24T06:50:51","guid":{"rendered":"https:\/\/ye1o34zhk8.onrocket.site\/?p=40415"},"modified":"2021-03-04T16:02:43","modified_gmt":"2021-03-04T10:32:43","slug":"loop-checking","status":"publish","type":"post","link":"https:\/\/instrumentationtools.com\/loop-checking\/","title":{"rendered":"What is Loop Checking?"},"content":{"rendered":"\n

The Loop checking<\/strong> is defined as pre-Commissioning activity which is initiated after installation of instruments in the field and carry out the instrument loop checks between installed field instrument and respective control system i.e. PLC or DCS.<\/p>\n\n\n\n

What is Loop Checking?<\/h2>\n\n\n\n
\"What<\/figure><\/div>\n\n\n\n

Loop Check :<\/h2>\n\n\n\n

An operational check of the field, controller and HMI<\/a> elements of a control loop<\/a>. A Loop Check is intended to ensure the integrity of the following.<\/p>\n\n\n\n

The field sensing device is properly installed in accordance with engineering specifications.<\/p>\n\n\n\n

The field sensing device is calibrated in accordance with engineering specifications.<\/p>\n\n\n\n

The field sensing device is properly connected to it\u2019s communication path to the Distributive Control System Controller. (e.g. Current Loop, Multiple device Bus Communication Protocol, etc.)<\/p>\n\n\n\n

The field sensing device develops and transmits a proper analogous signal in response to a variable impressed upon it or a simulation command issued to it.<\/p>\n\n\n\n

The corresponding logic in the DCS Controller<\/a> is ranged accordingly for the field sensing device analog and engineering units.<\/p>\n\n\n\n

The HMI of the DCS Controller accurately displays the engineering unit response to the signal of the field sensing device.<\/p>\n\n\n\n

Alarm points are properly entered into the logic of the DCS Controller and the HMI displays and logs these appropriately as they are reached.<\/p>\n\n\n\n

Where control functionality is required, that the signal from the field sensing device is received by the control algorithm and generates the appropriate corrective output signal.<\/p>\n\n\n\n

If present, the field control device, (e.g. Control Valve, Variable Speed Control etc.), is properly installed in accordance with engineering specifications.<\/p>\n\n\n\n

The field control device is calibrated in accordance with engineering specifications.<\/p>\n\n\n\n

The field sensing device is properly connected to it\u2019s communication path to the Distributive Control System Controller. (e.g. Current Loop, Multiple device Bus Communication Protocol, etc.<\/p>\n\n\n\n

The Field control device responds appropriately to the corrective signal received from the DCS Controller and that this action is appropriate to the desire process variable.<\/p>\n\n\n\n

Where specified, the response action of the valve is correctly transmitted to the DCS Controller and displayed on the HMI.<\/p>\n\n\n\n

SUMMARY<\/h4>\n\n\n\n

The Loop Check<\/a> is intended to locate and identify deficiencies in the Field\/Controller\/HMI interface. This includes, but is not limited to, wiring and cabling issues, engineering issues and mechanical installation issues.<\/p>\n\n\n\n

It is not the focus of the Loop Check to correct any deficiencies found. Full information concerning the deficiency is captured and passed on to the appropriate parties for correction. Minor corrections can be accepted, but this should be limited in scope.<\/p>\n\n\n\n

Procedure:<\/h2>\n\n\n\n

A list of Loops is collected and identified by Tag Number.<\/p>\n\n\n\n

Loops are grouped by Location, Availability, System, Equipment or other criteria. (Note: Locational Grouping of Loops results in the most efficient execution of Loop Check.<\/p>\n\n\n\n

The field team can be routed in a logical geographical progression of one device to another adjacent device without time loss for accessing different floors, buildings, plant sections etc.<\/p>\n\n\n\n

Loop availability can prevent this. If at all possible, Loop availability should be planned to accommodate Locational Grouping)<\/p>\n\n\n\n

Each loop is assigned a separate unique folder.<\/strong><\/p>\n\n\n\n

Each Loop Folder is populated with either a comprehensive Loop Sheet, and\/or individual elements, consisting of the following<\/p>\n\n\n\n