A recorder thus records electrical and non-electrical quantities as a function of time. His record may be written or printed, and later on, can be printed examined and analyzed to obtain a better understanding and control of the processes. Currents and voltages can be recorded directly while the non electrical quantities are recorded indirectly by first converting them to equivalent currents or voltages with the help of sensors or transducers.
The ever increasing emphasis on automation continuously recording instruments is finding many applications in industry. One of the important considerations in an instrumentation system is the method by which the data acquired is recorded. The recording method should be consistent with the type of system. If we are dealing with a wholly analog system, then analog recording techniques While on the other hand, if the system has a digital output, digital recording devices are used.
Thus there are two types of recording device: (a) Analog recorders (b) Digital recorders They are broadly classified into two categories (1) Graphic recorders (2) Scholarship recorder (3) magnetic tape recorder Graphic recorders generally are devices which display and store a pen and ink record f the history history of some physical event Basic elements of a recorder include a chart the deplaning and storing the recorded information , a stylus moving in a proper relationship to the paper and suitable meaner of interconnection to couple the stylus to the source of information.
This are classified into two categories (I) Strip chart recorder (it) X-Y recorders (I) A long roll of graph paper moving vertically A system for driving the paper at some selected speed . A speed selector switch is generally provided (iii) A stylish for making marks on the moving graph paper . He stylus moves horizontally in proportional to the quantity being recorded (iv) A stylus driving system which moves the stylus in a nearly exact replica or analog of the quantity being recorded. Galvan type recorder (ii) Null type recorder