Section 12 — Instruments and Controls

Receiver Instruments

IPE Engineering Practice IPE-EP-12-1-4

Document number: IPE-EP-12-1-4 · Section: 12 — Instruments and Controls

SCOPE

This Practice covers the detailed requirements for the selection of receiver instruments.

• Electronic receiver instruments shall be supplied in strict accordance with EP 12–1–4 DS, this Practice, and other referenced Refining Practices and Industry Standards.
• Where special features or improvements over the Practice are required as determined by the Owner, or Owner’s Engineer, these shall be specified on the Instrument Data Sheets and shall be adhered to by the Vendor.
• Any deviation from this Practice shall be approved by the procedure described in EP 1–1–3.
• A revision bar indicates all changes made to Revision 1.

2.0 REFERENCES

STANDARDS AND PUBLICATIONS

DEFINITIONS

• Contractor - Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
• Inspector - A Inflection Point Engineering, LLC . appointed engineer or inspector.

• Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a manufacturer by a contractor or the Owner. An indirect order is one issued to a manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.

• Owner - Inflection Point Engineering, LLC.
• Owner’s Engineer - A Inflection Point Engineering, LLC. appointed engineer.
• Purchaser - The party placing a direct purchase order. The purchaser is the Owner’s designated representative.

DESIGN AND MATERIALS

• General
• All receiver instruments shall be calibrated for use with a transmitted signal of 4 to 20 mA DC unless otherwise specified. They shall be capable of being used with ISA S50.1 2U Type (two wire) or 4 (four wire) transmitters.
• Control room type instruments designated as 4 to 20 mA input shall be used with field transmitters and shall be capable of powering 2–wire transmitters. Control room instruments designated as 1–5 V will be parallel wired across the input of another receiver.
• Unless otherwise specified on the Instrument Data Sheets, all instruments shall be miniature type suitable for panel mounting in multiple unit shelves furnished with the instruments.
• All receiver instruments shall have a high input impedance of at least 50,000 ohms at balanced or unbalanced pen scale positions. The receiver shall be suitable for parallel wiring of inputs across a common dropping resistor.
• All instrument cases shall be equivalent to general purpose NEMA Type 1 in accordance with NEMA ICS 6 unless otherwise specified on the Instrument Data Sheets. Local receiver instruments shall be suitable for the area classification as specified on the Instrument Data Sheet.
• All instruments shall be identified with a permanently attached tag bearing the device’s item tag number. Identification tag shall be located so as to be visible when the instrument is in its normally installed position.
• Design and materials not specified shall be in accordance with the manufacturer’s standards. Minimum design shall conform to National Electric Code (NEC) with applicable listing by either Underwriters Laboratories (UL) or Factory Mutual (FM).
• Unless otherwise specified by the Owner’s Engineer, the power supply for the control panel instruments shall be nominal 120 V, 60 Hz, AC.
• Scale windows shall be made of glass or clear plastic.
• All instruments shall be RFI immune. Manufacturers shall test their equipment per SAMA Standard PMC 33.1. All instruments shall be affected by no more than 1 % of span when exposed to a field strength of 10 volts per meter (Class 2) with a frequency range of 50 to 500 MHz (bands b and c). Preference will be given to those instruments which meet this criteria at field strengths of 30 volts per meter.

• Vertical Scale Indicators

Indicators shall us pointers as specified in 4.2.4 to indicate the variables specified on the Instrument Data Sheet. The pointer for the first measurement shall be red, and the pointer for the second measurement shall be green, unless otherwise specified.

• Recorders
• Recorders shall have nominal dimension of either 6 inch wide by 6 inch high or 3 inch wide by 6 inch high, unless otherwise specified.
• Recorders shall be furnished with a supply of charts and ink for 3 months operation.
• Recorders shall be furnished with electric chart drives providing a chart speed of approximately 3/4 inch per hour, unless otherwise specified on the Instrument Data Sheets.
• Recorder charts shall be displayed as follows:
• Flow: Red
• Temperature or Level: Green
• Pressure: Blue
• Two pen conflicts: Violet
• Controllers
• Controllers shall be of maximum nominal size 3 inch wide by 6 inch high, unless otherwise specified.
• Controllers shall incorporate both proportional and integral actions unless otherwise specified in 12–1–4 DS Instrument Data Sheets. Derivative action is required for all temperature and analysis controllers.
• Tuning constants shall be adjustable from the front of the control panel as follows:
• The proportional band from at least 5% to 500%
• Integral action from at least 0.02 to 100 minutes per repeats.
• Derivative action from at least 0.04 to 20 minutes.
• All controllers shall be furnished with an automatic–manual control unit for procedureless ”bumpless” transfer from automatic to manual operation and vice versa. Provision shall be included for manual adjustment of the controller output signal with the control mechanism bypassed.
• Digital controllers shall have digital readout displaying actual engineering unit. Controllers shall be furnished with an indication of controller output value in percent. Valve position (open– closed) shall be clearly identified at each end of output scale.
• When the set point is specified as an electronic input (such as cascade). the mechanism shall be designed to maintain a linear relationship between the value of the setting signal from a primary controller and the value of the set point to secondary controller. The secondary controller shall also be provided with the following switching functions.
• Manual setting of the set point from the secondary when the secondary controller is isolated from the primary controller.
• Manual adjustment of the secondary controller output signal with the control mechanism bypassed.
• Electronic setting of the set point by a primary controller.

• The secondary controller of a cascade loop shall have a remote/local/manual/auto switch.
• When specified, the controller shall be supplied with an anti–reset windup feature to prevent saturating the integral circuit when the controller is off control for long periods. The primary control of a cascade loop shall have tracking capability (external feedback) to prevent reset windup.
• Controllers that cannot be service within in the “manual” position shall be furnished with a service manual station to permit the transfer of the controller to a service manual station without interrupting the controller output signal. The service manual stations shall be furnished with necessary cable and plugs.
• Digital control program execution rate shall be minimum of 4 times per second.
• Controller output shall go to “zero” when there is a power loss. Output shall remain at zero when power returns until manually reset by the operator.
• Auxiliary Units
• Unless otherwise specified on the Instrument Data Sheets, auxiliary units, such as manual loading stations, ratio stations, auto/manual stations, and bias stations shall be of the miniature type with a maximum nominal case size of 3 inch by 6 inch high.
• All units with automatic–manual selection capability shall be furnished with an indicator for the “automatic” signal input.
• Ratio stations shall be furnished with an additional indicator scale to display the ratio setting.
• Manual loading stations shall be furnished with an indication of station output signal. An indicator shall be furnished to indicate a process variable if required by the Instrument Data Sheet.
• Instrument Mountings
• All Instruments specified for flush mounting shall be furnished with fastenings necessary for flush mounting of the devices to the instrument console.
• Surface mounted instruments shall be supplied with fastenings suitable for mounting on a vertical surface.
• When specified, instruments shall be furnished with multiple unit shelves (housing) in the quantities and unit capacities specified on the Data Sheet.
• Shelves shall be designed so that instruments may be arranged in any desired layout.
• Individual shelves shall house from one (1) to ten (10) nominal 3 inch by 6 inch instruments or a combination of 3 inch by 6 inch and 6 inch by 6 finch instruments.
• Sufficient length of cable shall be furnished to allow complete withdrawal of the instruments from the front of rack or panel without interrupting operation.
• Withdrawal of any one instrument shall not interfere with other instruments housed in the same shelf.
• All signal and AC power terminations shall be fully enclosed. No free hanging wires are permitted.

PERFORMANCE

• Accuracy
• Accuracy of recorders shall be ” 0.5% of calibrated span.
• Accuracy of measurement and set point shall be ” 0.5% of calibrated span.
• The indicating element of a recorder or indicator shall not remain stationary when a change greater than 0.1% of the specified range occurs in the input signal.
• The output signal of a controller shall show a response when a change greater than 0.1% of the specified range occurs in the signal applied to the input at a proportional band setting of 100%.
• The effective value of the set point of a controller shall not be affected by adjustment in the width of the proportional band.
• Repeatability

Repeatability shall be ” 0.1% of calibrated span.

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