SU506762A1 - Multipoint system for automatic temperature control - Google Patents

Description

one

The invention relates to a measurement technique, in particular to instruments for monitoring and measuring temperature.

The known multipoint systems for automatic temperature control mainly satisfy most requirements both in the number of controlled points and in speed.

However, there are industrial facilities (for example, gas pumping, energy units or power units), which require constant temperature control at some points with the inclusion of control equipment in the system and are protected by the unit. Turning off these units due to the false alarms of the temperature control equipment due to the malfunction of this equipment or the effect of external interference leads to large economic losses.

The known devices for temperature control do not have the protection against false alarms from the effect of industrial noise, as well as upon exit from the device itself.

To improve the reliability and reliability of the control, the proposed system introduced a counter, strobing, its device, fault signaling device, two differentiating devices and three coincidence devices, one of the inputs of the alarm unit through the fault, coincidence alarm devices, its device and A control meter is connected to the outputs of a pulse voltage source and a threshold device, and another input is connected to the output through a gate device. lnational block.

FIG. 1 shows a block diagram of the proposed system; in fig. 2-5 - graphics, as described, its principle of operation.

The system contains sensing elements 1, for example resistance thermometers, which are connected to the selector 2, the amplitude discriminator 3 and the source 4 of the pulse voltage.

The output of the diode selector is connected to a threshold device 5, to which a source of pulsed voltage is connected. The output of the threshold device 5 is connected to the executive unit 7 via the control clock 6. The output of the executive unit 7 is connected to the inputs of the strobe device 8 and the coincidence device 9. The output of the strobe device 8 is connected to another input of the unit 7; the output of the coincidence device 9 through the forming unit 10 is connected to the alarm unit 11 and the assembly of the assembly 12, to the second input of which through the differentiating device 13 an output is connected

The gate device 8, which is connected to the second input of the I block. The output of the control counter is connected to one input of the coincidence device 14, and the output of the pulse voltage source is connected to the second input through a differentiating device 15. The outputs of the coincidence devices 12 and 14, as well as the output of the amplitude discriminator 3, are connected to the inputs of the malfunction alarm device 16, the output of which is connected to the input of the block 11.

The system works as follows.

From the sensing elements 1, fed from source 4, through the selector 2, signals are fed to the threshold device 5. There is also a signal from source 4 to receive a reference voltage proportional to the set alarm level.

When any of the sensitive elements reaches a temperature higher than the equivalent value of the reference voltage, the threshold device generates a signal representing a burst of pulses that goes to the control counter 6. The number of pulses in the packet is greater than the minimum required to fill counter 6. Signal the output of the counter 6 turns on the executive unit 7, which, in turn, turns on the gate device 8. From the gate device B, a short pulse is sent to the executive block 7, the end of which the execution unit 7 is turned off.

From the second output of the strobe device 8, a pulse pulse is supplied to the input of the coincidence device 9, the duration of which is approximately equal to one and a half periods of the frequency of the source 4 of the pulse voltage, and which starts after the first output pulse of the strobe device 8 has finished. g of the executive unit 7, which posusgat on the forming unit 10 and further on the alarm 11 11, and from it to the external control circuits of the alarm system and the automatic tiki.

This is how the device works when the device is fully operational and when there is an emergency temperature at any controlled point.

The device for temperature control has a system of protection against false alarms of the alarm when exposed to external interference and the following cases of device malfunction.

In case of malfunction of the sensitive elements and lines connecting them with the control device, the amplitude of the pulses from the sensitive elements goes beyond the limits of operating values and in this case the output

amplitude discriminator 3 a signal appears that includes a fault alarm device 16. The device 16 blocks the switching on of the block 11 and generates a fault signal to the external signaling circuits.

when the threshold device 5 and the forming unit lU malfunction, which means that the threshold device or counter spontaneously turns on, at the output of counter 6 a pulse appears, the leading edge of which coincides in time with the leading edge of the pulse from the pulse voltage source 4. In this case, at the input of the coincidence device 14, two

signal from counter 6 and source 4. The signal from the output of the coincidence device 14 turns on device 4b. Further, the protection system works, as in the previous case (see Fig. 2 and 3).

The operation of the protection system against false alarms for the remaining faults is explained in FIG. 4 and 5.

When the execution unit 7 goes out of operation, when it spontaneously turns on and

is not turned off from the gating pulse, signals from the executive unit 7 and the gating device 8 are sent to the matching device, and the signal from the matching device passes through the forming unit 10 to the matching device 12, to the other input of which the signal from the gating device 8 is fed through the differentiating the device 13 (the alarm block 11 is thus blocked from being turned on by the gating device 8). The signal from the output of the joint 12 includes a fault signal device 1b. Further, the protection system works, as in the previous cases.

Claims (1)

Invention Formula A multipoint system for automatic temperature control, comprising sensitive elements, a source of pulse voltage, an amplitude discriminator, a threshold device, an execution unit, a forming unit and an alarm unit, characterized in that increase the reliability and reliability of the control, a counter, a gating device, a fault alarm device, two differentiating devices and three coincidence devices, This is one of the inputs of the alarm unit through the fault signaling, connecting devices, differentiating device and control meter connected to the outputs of the pulse voltage source and the threshold device, and the other input through the gate device connected to the output of the execution unit. And, pCZIbH / H4JLJhr I F I f I hH-f-KZJ