MECHAN-TRONICS VARIABLES

Mechanical instruments provides an accurate and economical means of measuring the status of nearly all process system. The instrument that measure all critical performance of process system are essential for all predictive and plant improvement programs. The information derived from process are used in-conjunction with vibration monitor,parameter infrared, interrogator to monitor predictive maintenance instrument, and other devices.  Mechantronics provide means for maintenance experts to liaise effectively  in any technical challenge and the method to enhance appropriate troubleshooting. and optimize the process. And the instrumentation aspect is divided into two variables i)Monitoring and Control..
 Process Monitoring: Mechanical instrument are mostly used to measure, record and trend variation in process parameters, such as pressure, low or temperature. In most cases the instrument convert mechanical displacement or movement of its sensor into corresponding proportional movement of a pen or gauge. These instrument generally transfer actual value of the measured parameter by means of a linkage mechanism,to a graph or displacement that is a part of the unit.
Process Control: The principle of the instruments are identical to those for the purposes of monitoring.In this instance, the instrument will translate the actual mechanical displacement into a proportional output, either pneumatic or electrical, that is used by the system control logic to adjust the process parameters.
Most process variable could be measured with mechanical instruments and may include the following:i. flow, ii. pressure iii. temperature iv.level and v. positions.The limitation are few, e.g pressure in micron range , temperature above 537.8 oC, and analysis of fluids.New designs and  materials for actuating element provides acceptable accuracy and sensitivity that are suitable for most applications These factors in addition to ruggedness include low cost and ease of maintenance,have resulted in an increasing use of mechanical instrument.for both monitoring and control of process system.In the industry they are classified by case size,type of recorders or indicators and form of charts or scales,In addition to the record or indication for the process variable instrumentation could provide automatic control integration of flow and adjustable alarm or signals for abnormal operating conditions.
Recording Instrument:A relatively small number of recorders are used to record only the value of the process variable,  A large number of flow with the total amount indicated by a mechanism.The majority of the measuring instrument are used for automatic control application.For this applications, 254 (mm) to 308.4 (mm) charts are the most desirable because of greater accuracy in reading and positioning the set point and a better opportunity of observing process trends .  Ink of different colors could be used and by using eccentric scale which follow the time line of the chart,and a pointer on the pen arm. It is possible to have a combined recording and indicating instrument. The use of  printer has been in used , for  so long that, they are recently available with literally thousands of calibration,including those for a single variable and others having multiple segment for two or more variable. The standard hour chart speed is the 24 hours revolution but many other speed and the require mechanism are available. The drive mechanism may be electric, hand worn spring drive or pneumatic operated.