Characteristics of optoelectronic discrete displacement converters with hollow and fiber light guides

D ovs .= D p +4 y ,

(21)

where: D_p – end diameter of PVA 5; y – parameter associated _with Dovs .

(22)

where: U ₀ – the angle between the axis and the angle of entry of the beam; x ₀ – the distance between the ends of the ODC and FLG.
From (22) it follows:

	(23)
	(24)

The illuminated surface of the input end of the FLG 6 is equal to

(25)

Light flux incident on the end of the OVS 6 and therefore on PI 8 is equal

(26)

where: – light intensity from AI7; ρ ₁ – reflection coefficient of the ODC surface .



Fig.8. Physical model of an optoelectronic liquid level device.

Fig.9 . Physical model of the ODC installed on the top cover and the change in the illuminated surface S _{osv (x)} .

Analysis of the graph in Fig. 10 Ф ₀ (х)/Ф ₀ (х ₀ )= f ( x ) shows that the sensitivity of the ODC has a maximum value in section I and a minimum in section II . Section III has less sensitivity than section I.

Fig.10. Dependence of F ₀ (x)/F ₀ (x ₀ ) (a) and U _out (x)/ U _out (x ₀ ) on the magnitude of the ME displacement.



a )

b )
Fig.11. Physical model of ODC with transverse movement of the ODC along the coordinate U: a ) – physical model; b ) – change in the illuminated surface S _p ( y ) .

Figure 11, a shows the physical model of the ODC with transverse movement of the ODC 4 , along the y coordinate , according to which the luminous flux Ф ₀ ( y ) begins to illuminate the reflective surface of the ODC 4 not at y=0 , but at the initial value

(27)

With further movement of the reflective surface of the float, the surface S of the float is _illuminated (y) changes in the form of a segment (Fig.11, b), the area of which changes according to the expression

(28)

where: AB is the base of the segment.
At

	(29)
	(30)

In turn, the luminous flux Ф reflected from ODC 4 _from ( y ) falls on the input end of the FLG 10 with an area that , starting from changes according to the formula

(31)

to the coordinate value

(32)

y changes according to the expression

(33)

The luminous flux when moving ODC 4 along the y coordinate incident on the radiation receiver 2 is determined by the expression

(34)

and the output voltage of the bridge circuit and the luminous flux Ф ₀ ( y ) changes according to the graph in Fig. 12.
Light flow falling on S _osv (y) will change according to the graph in Fig. 12.

Fig.12. Relative value change graph when moving the EM along the Y coordinate .

Thus, when the ODC 4 moves along the y coordinate in the section of the FLG installation corresponding to the controlled movement, an output signal is generated in the form of a pulse for monitoring and control systems.

In general, the process of converting the signal about the liquid level H₁ when approaching the maximum value H_1max, the measurement graph F₀ has the form shown in Fig. 12. Based on theoretical and experimental studies, it was found that as H_{1 approaches} H2max _, the lower and distance x = 8-10 mm F₀ increases and reaches a maximum at x = 4 mm and with a further increase to N₁ = P_1max luminous flux Ф ₀ becomes equal to zero (Ф₀ =0) due to the lack of reflection of the luminous flux by the axis of the liquid level surface (x=0 ). (Fig.12).
When the radiation receiver is connected to the bridge circuit (Fig.13, a) and the equality of the resistance of the radiation receiver R _pi to the resistances of the other arms of the bridge circuit R ₁ , R ₂ and R ₃ when reaching the maximum luminous flux F _ohms (Fig.12) the output voltage of the equilibrium bridge will be zero ( U _out = 0) . The op-amp operational amplifier (Fig.13) will not supply voltage to relay P₁ and its normally closed contact P _1-1 will close the optical OS and audio alarm circuits about reaching the maximum level P _1max . When the liquid level decreases H _{1 1max,} the reflective surface of the level will move lower, the luminous flux Ф ₀ in DPPV will decrease sharply. The bridge circuit will become unbalanced and the output voltage U_{out appears} ≠0 , which through the op-amp and relay R₁ will disconnect the OS and ES circuits, while pumps and other devices can be connected to the monitoring and control circuit.
The principle of constructing the second ODC design is similar to the first ODC design (Fig. 7). When the liquid level H=H_{1 is reached,} float 4 will be opposite the ends of the light guides 9 and 10 and the luminous flux Ф₀ will reach a maximum F_ohm , while the resistance of the radiation receiver 12 will change sharply and the bridge circuit (similar to Fig.13) will be out of balance