what is the difference between two wire and four wire transmitter?

Answer 1

In instrumentation, a 2-wire transmitter carries both the signal from the gauge and the power to the gauge on a single pair of wires. This may either be a 4-20 mA type arrangement, or it may be DC power and a strictly AC signal (isolated with capacitors or transformers), or the gauge may not need power (as in a piezoelectric transducer) but a pair of signal wires, only.

In a 4-wire system, the power to the gauge is on one pair of wires, while the signal is carried on the other pair of wires. Bridge-type gauges usually use a 4-wire system.

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Answer 2

2 Wire Transmitter

Answer 3

A 2 wire xmitter is powered by the mother instrument. The output signal(4-20ma) is returned on the same wires that powers it. the main purpose of this design is to reduce wiring cost, standrdisation of circuits, and above all, to kep all the transmitters at same ground potential.
A 4 wire inst. has design flexibility to utilize any power like, 230vac, 24 vdc or 110 vac. It can feed the signal to any mother instrument. Wherever the basic sensor of an instrment needs power other than 24 vdc (like chemical analyser) u have no choice but to use a 4 wire xmitter.

Answer 4

Don't know why everyone says the 4 stroke is cleaner, new modern 2 strokes actually have less emissions than most of the new 4 strokes fuel consumption depends on brand. As a buyer what you need to know is: 4 Strokes: cost more, run smoother, some are quieter, require more maintenance, last longer. 2 Strokes: Cheaper, weigh less, less maintenance, more powerful.