DD223027A1 - PROTECTION DEVICE FOR THE PERMANENT SHUTDOWN OF CONTROL AND CONTROL SYSTEMS FOR UNUSUAL OPERATING EXPENSES - Google Patents

Abstract

The invention relates to a protective circuit arrangement, which causes a permanent shutdown desselbigen in undesirable Betriebszustaenden in any control and / or control system (4) for a variety of processes. According to the invention, this is achieved by a circuit combination of: a switching element (1), preferably a transistor (2) with a negative temperature characteristic, preferably thermistor and a fuse insert, preferably a fine fuse. The signal is output by a signal from the safety or monitoring system 1), so that in conjunction with the downstream resistor (2) an electrical interruption of the power supply of the control and / or regulating system (4) by means of a fuse link is achieved.

Description

Title: Protection device for permanent shutdown of SS = SSB control and regulating systems in case of undesired operating conditions

Field of use:

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The invention is used in electronic control and / or regulating systems in which a elekt ro mechanical or electronic switching element is controlled in an undesirable operation by an electrical or electronic security or monitoring system «

It is meaningless for the invention which types of physical state variables (process parameters) are to be saved or monitored or whether they are analog or digital quantities.

Possible applications include z, B, the limitation of temperature, pressure, humidity, level and flow velocity in heating, refrigeration, air conditioning, ventilation, storage and conveyor systems in industry and agriculture ·

Characteristic of the known technical solutions «. * -

It is known that in order to limit physical state variables (process parameters) which must be kept within certain limits in a control and / or regulating system, there are a plurality of measuring, safety and monitoring devices which are capable of safety shutdowns make. Such MeQ, safety and monitoring devices include, for example, thermal hazard detectors, contact thermometers, bi-metal switches, contact pressure gauges, fluid level switches or electronic limit switches, which, in conjunction with their control and / or control unit, are designed to detect undesired operation, B. · B. Exceeding the limit value, can trigger or even prevent an automatic restart. .

In the majority of all safety or monitoring devices, after the occurrence of an undesired operating state, avoidance of the automatic restarting is required for safety reasons. Furthermore, even a simple activation of the control and / or regulating device, without elimination of the cause, is inadmissible for the undesired operating state.

Known technical solutions are:

- Circuit-related interruptions by electromechanical switching elements (for example, lifting a latch);

- Over-temperature release with bi-metal;

- temperature-dependent Auslötsicherungen; electronic limit switches etc

Object of the invention:

The object of the invention is to provide a protective device which, regardless of the type of physical state variable (process parameter) to be controlled or changed in a control and / or regulating system after occurrence of an undesired operating case, preferably limit value transmission lines and in cooperation with a safety and or monitoring device performs an electrical line interruption until the cause of the unwanted operating event. Furthermore, the electrical interruption, which is to effect the protection of the control and / or regulating system as well as the limitation of a physical state variable (process parameter), to initiate delayed in time.

Preferably, the protective device for constantly changing physical state variables (process parameters) is to be interpreted, where appropriate, the protective device may also take over an electrical overload protection of the control and / or regulating system in addition to its actual puncture.

Essence of the Invention: H

The essence of the invention is that in a control and / or regulating system (4), regardless of the nature of the state variable (process parameter) (6) to be controlled or changed, after occurrence of an undesired operating state, for example exceeding the limit, by technical Failure of the control or regulation and in conjunction with a safety or monitoring device (5) to eliminate the causes of undesirable operating condition an electrical line break is made according to the invention this is the fact that when signaling an undesirable operating condition by a safety or monitoring system (5) Switching element (1), preferably transistor, is controlled so that its contact resistance is as small as possible and thus, due to the simultaneous use of the operating voltage (U _ß ) of the control and / or regulating system, an electrical current flow (Js) About the switching element ( 1) and a NaOHgesohalteten resistor with negative temperature characteristic (2), for example, thermistor flows.

The self-heating of the resistor (2) caused by the current flow (Js) reduces its resistance value and thus also the resistance of the circuit of the protective device, which leads to an increase of the current flow (Js). Furthermore, by a the control and / or regulating system (4) and the safety or monitoring system (5) upstream of fusible insert (3), preferably electrical fine-fuse, melted, whereby an interruption of the power supply of the control and / or regulating system ( 4) and the Be *. limit of a physical state variable (process parameter) (6) is reached.

The invention is based on the security requirement that the occurring in autonomous controls and regulations unwanted operating conditions, which were usually caused by faults, errors or failures in the control and / or regulating system, must lead to a permanent shutdown of the entire system, so that a restart again only

is possible with an aid.

Due to the inertia of the resistance change of the resistor (2), the protection device , with short-term response of the switching element due to disturbances, which are not caused by the control and / or control system, delayed in time effective »Thus, it is possible by the Safety device upstream safety or monitoring system (5) to make an immediate shutdown in certain situations, but only after a determinable by the parameters of the resistor (2) delay time becomes permanent and safe ·

FIG. 1 shows the operating principle of the invention. The following advantages are achieved:

- avoidance of additional switching elements for switching off in case of undesired operating states;

- No assembly times when using the protective device required;

- low material expenditure;

- no restrictions on application for various undesired operating states and physical state variables (process parameters);

- avoidance of unwanted permanent protection reactions in case of short-term disturbances;

- ensuring lasting safe protection;

- Integration of control and / or regulating device, safety or monitoring device and protective device on a printed circuit board is possible;

- Determination of the Abschaltwertes the state size (process parameters) by upstream safety and / or monitoring system.

Protective device for permanent shutdown in case of undesired operating conditions

Claims (6)

C- Inquiry:, O. Protection device, characterized in that in unwanted operating states, a shutdown of the control and / or regulating system without subsequent reconnection by a fuse link (3) preferably fine ·. ' insurance. 1 / protective device according to claim 0, characterized in that a fuse link (3), preferably a fuse, is triggered by an increased current flow (Js) as a result of the self-heating of a resistor having a negative temperature characteristic (2), 2. Protection device according to claim 1, characterized in that the protective reaction by a Sicherheite- or monitoring system (5) controlled switching element (1), preferably transistor, is initiated. 3. Protection device according to claim 1, characterized in that after triggering of the safety or monitoring device (5) a different time delay of the permanent shutdown of the control and / or regulating system (4) can be achieved. 4. Protection device according to claim characterized in that at short-term release of the safety or monitoring device, as a result of disturbances that are not caused by the control and / or control system, no protective reaction is initiated. 5. Protection device according to claim 0, characterized in that a fuse link (3) guarantees both the protection of the control and / or control system in unwanted BetriebszustHnden as well as electrical overload. 6. Protection device according to claim O to 4, characterized in that react at control and / or control processes of different physical state variables (process parameters) auf.unerwünschte operating conditions can. hiiSPZU 1 somersault drawings