Processing solids, liquids and gases at different pressure / temperature / flow / chemical quality is essential in industry related to petroleum or petroleum product.
The process variables (pressure, temperature, flow etc.) are monitored in order to achieve optimum output production to specified quality.
Instrumentation is the interface with actual physical values of process variables and a presented readable data for operator.
COMMON DISPLAYS:
- Indication
All process parameters such as flow press, temperature level etc is made available on a visual mode – a screen or indicator.
- Recording
The engineering values of all parameters are constantly recorded on a hardware copy for trend analysis.
- Control
The desired value is remembered by instrument so that the system tries to maintain the manipulated variable with in the required desired value or set point.
- Warning
If any process parameter is turning to overshoot a limit on either side beyond the desired value, an audible and visual alarm as an early warning to prevent any process upset. Alarm annunciation with accept reset and first up flashing functions are available.
- Shut Downs
The safety of plant people and environment is ensured by shutting down the plant when operating parameters exceed the most unexpected set points and cannot be resumed to normalcy within a safe time.
Instrumentation is a network of many devices in the field and control center from where process is being operated.
Networking includes hard wiring, radio wave linking, and similar communication systems.
Devises are electronic / mechanical components designed for measurement and control. Any of these can fail to cause the function it does to stop.
The normal production process is then interrupted.
These interruptions due to failures are generally called Operational Problems” (instrumentation)
COMMONLY OCCURRING INSTRUMENT PROBLEMS
I. Display
1. Not responding
- Failed – Gone Max/Min
- Erratic
II. Trend
1. Not responding
- Failed
- Erratic
III. Control
- Lost control
- Hunting
- Slow response
IV. Warning
- Failed
- False
V. Shut Down
- Failed
- False
