Typical Guideline for a Control System Doc

1. Typical Control System Design Document/Guideline :
1.0 Measurement and Control Devices Design :
1.1 Instrument List
The Instrument List tabulates instrument numbers, description, service and P&ID numbers in
addition to other information on individual devices that might be required for a given project.
1.2 Instrument Specifications
Specifications for commonly used instrumentation are prepared in standard ISA data sheet
format and contain information from P&ID's, vendor catalogs, calculations, and piping
drawings. Special instrumentation such as analyzer systems may require a complete
specification document.
1.3 Local Enclosures
Panels or racks mounted near the process equipment which contain field devices such as
transducers, solenoids, and I/P or P/I converters. They are normally NEMA 4 design with
many devices pre-wired to industrial terminal strips.
1.4 Local Control Panels
Operator interface panels with controllers, pushbutton and indication needed for process local
startup or local control of a specific operation.
1.5 Instrument Air Piping
These drawings indicate the general location of all instrumentation that require field piping,
air connections, or pneumatic signals. They are made to scale so that a reasonable estimate of
material quantities can be made for construction and they are a scope document for
subcontract work.
1.6 Construction Specifications
Specifications that describe the work required to install instrumentation by field contractor.
Typical specifications include calibration and commissioning, installation work scope,
instrument wiring, and control pnael fabrication.
1.7 Instrument Systems Wiring Diagrams
Drawings produced to provide connection information for complicated systems such as
analyzers, halon, L.E.L., and chromatograms.
1.8 Instrument Installation Details
The Instrument Installation Detail shows the piping arrangement for the mounting and
connection of field instrumentation items. These drawings contain a complete Bill of Material
for piping requirements and a reference to the instrument tag numbers.

2. 1.9 Purchase Requisitions
All work necessary to complete purchasing on instrumentation including requisition
preparation, bid tabs, and purchasing assistance.
2.0 Control Systems Hardware Design :
2.1 Systems Specification
Formal Document generated to obtain competitive bids on process control systems, both DCS
and PLC based. The specification should include scope of control systems, I/O requirements,
system architecture sketch, functionality requirements, performance criteria, and vendor
responsibilities.
2.2 System Equipment List
Supplement to the specification to detail deliverables from the selected vendor. In some
projects with a pre-selected vendory, only the equipment list is prepared.
2.3 Cabinet Arrangements
Arrangement of I/O and controllers in the DCS system cabinets, or PLC cabinets/panels. Can
be formal drawings or sketches given to the selected vendor who prepares the formal
drawings and documentation.
2.4 Console/Panel Arrangement
Design of control room console based on standard offering from vendor, or custom consoles
required for integrating operator interface equipment from various vendors. Usually a desk
type arrangement without a vertical section, however, large control room panels are also
included in this group.
2.5 Power Distribution
Design of the power feed to the control system and to each cabinet or controller requiring
power. Includes distribution panel and details for connection to the individual devices.
2.6 Grounding
Design of a system grounding system to comply with the vendors requirements and the NEC.
Includes ground connection to cabinets, consoles, and cabling to the gorund bus.
2.7 Control Room Arrangement
Details the location of all control equipment in a control room. Can be a formal drawing or
included as part of an architectural drawing.
2.8 Loop Drawings

3. Drawings detailing all components of a single control loop including all information
necessary to understand, test, and operate the loop. Loops can include both analog and digital
components.
2.9 I/O Schematics
Drawings that functionally detail electrical connections to control components used in digital
control such as process switches, limit switches and solenoids. These are normally directly
connected to I/O modules.
2.10 Motor Control Schematics
Drawings that functionally detail electrical connections to motors that are controlled from the
process control system through I/O modules.
2.11 Transducer/Interface Panels
Control room mounted panels that contain components required to interface field devices with
the control system. They can contain signal conditioning or isolating equipment suchas relays.
3.0 Control System Wiring Installation Design:
3.1 Wiring Block Diagram
Identifies all the main components in a control system such as panels, computers PLC's,
operator consoles, etc... These drawings show the general interconnection between
components and the wiring strategy to be used.
3.2 Field Device Connection Details
Details specifying conduit and fitting requirements and standard hook-up of instrumentation
and control devices.
3.3 Field Terminal Panels
Panels used as a central termination for multiple device cables from the main control room
location. Individual device wiring is run from these panels normally in conduit to the field
mounted device.
3.4 Conduit and Cable Schedules
Schedule or listing of cables defining the connection location at each end, conduit number,
type of cable, and wiring in the cable.
3.5 Control Device Location and Conduit Plans
Plan drawings of the process area that indicate the location of all control devices and diagrams
the conduit connection and routing to the devices from the control panels and terminal panels.

4. 3.6 Cable Tray Layout
Overall arrangement of control and instrument tray systems detailing the routing of tray
between field panels and the main control area. Required on projects with extensive cable
systems.
3.7 Wireway Layout
Overall arrangement of control and instrument wireway systems detailing routing of wireway.
Drawings can also include device locations.
3.8 Electrical Construction Specification
Specifications that describe the work required to wire the instrumentation by a field
contractor. Typical specifications include a work scope, wiring material description, and
testing requirements.
3.9 Electrical Material Specifications
Specifications of all material required for the electrical installation of the instrumentation. A
material takeoff of all material so that quantities can be established and ordered for
construction.
3.10 Control Room Wiring Layout
Conduit, tray, or computer floor layout for wiring to control equipment. Can be a separate
drawing or part of an area control plan drawing.
4.0 Process Control Design :
4.1 P&ID Input
The instrumentation representation on P&ID's must include proper loop representation,
tagging, and measurement and control device symbols.
4.2 Continuous Control Loops
Design of the control shceme for all continuous control loops is often completed on the P&ID
diagram. It can also be accomplished using SAMA control symbols for control algorithms.
Control loops must be completely defined prior to devoping DCS configuration software.
4.3 Discrete Logic Design
Discrete logic can be described in a structured narrative of process operation or on a diagram
using symbols for logic gates. A detailed design of logic must be completed before
programming can be complted on PLC projects.

5. 4.4 Operator Interface
Design of CRT based operator interface using process graphics, alarm screens, control
faceplates, trends, and text screens. The interface design is prepared in conjunction with
control logic to define how the operator interacts with the process to accomplish desired
control functions.
4.5 Process Control Operational Description
The operational description defines how the control system functions and the operator
interface for various modes of process operation. It is derived from the logic and operator
interface design.
4.6 I/O Definition
Definition of the I/O tagging, service description, location, range values and alarm limits. The
I/O definition forms the primary database for configuration of the control system.
4.7 PLC Software and Documentation
PLC code using a software development package with complete documentation capabilities.
The software is based on the logic and control loop design. Also includes operator interface
code for CRT displays.
4.8 DCS Software and Documentation
Generation of DCS configuration by utilizing vendor forms or development system. Normally
consists of an I/O point database and software connection of vaious control function blocks.
Also includes operator interface code for CRT displays. These are usually graphics and
faceplates supplied as part of the DCS system.
4.9 System Software/Hardware Testing
Simulation of the process operation to test the software functions. Testing is done at the
vendors fabrication location and can consist of test sofwtware or simple hardware I/O
switches and analog inputs. Also includes testing of system hardware components.
5.0 On Site Services :
5.1 Installation Supervision
Monitoring of the instrumentation contractor for installation, wiring, and testing of all I/O
devices and system components.
5.2 System Commissioning
Initial operation of the system from power up, to testing of I/O into the system for proper
operation. On completion of this task the system is ready for process start-up.

6. 5.3 Start-Up Assistance
Field verification of system software and standby operation during process start-up to make
on-line control system modification during the intial period of process operation.

7. 5.3 Start-Up Assistance
Field verification of system software and standby operation during process start-up to make
on-line control system modification during the intial period of process operation.