DE3742397C1 - Network analyser for indicating, analysing, recording, storing and indicating electromagnetic faults - Google Patents

Abstract

The detection of network irregularities and, in particular, the detection and interpretation of spurious peaks is gaining in importance in all areas of electrical engineering, but especially in electronic data processing, since the problems of so-called "electromagnetic compatibility" (EMC) owing to the connected consumers (loads) of the low-voltage supply network are also becoming ever more complex owing to increasing mechanisation. Conventional network analysers operate using the principle of the RF amplifier, and are complicated and expensive. It often occurs that devices have been influenced without analysers which are connected to the network having indicated anything. According to the invention, the signals and pulses are converted into electric variables which can be processed more effectively, with the result that with the simple cost-effective device frequencies of up to more than 100 MHz can be optically displayed, detected by memories, and interpreted more effectively by connectable auxiliary devices. Technicians and service staff have a valuable test aid in determining and interpreting disturbing mechanisms on the public low-voltage supply networks. <IMAGE>

Description

Ever since the Morse age, communications technology has Method used for electrical signals and impulses is in Computer age thanks to the pulse sequence and breadth faster semiconductor penetrated into areas that it make necessary, possibly occurring interference pulses to recognize in the fast rise area and time course to then take countermeasures that are necessary thus the device, the system or the system works satisfactorily.

It is obvious that a glitch that is associated with a useful signal is confused, is able to control, Production and monitoring facilities, for example in manufacturing or security areas endanger and possibly economically cause undeniable damage.

Standards for limit values and measuring methods for radio Malfunctions of electrical devices and systems are in following DIN / VDE or IEC sheets: DIN / VDE 0875/07. 77; DIN / VDE 0871/06. 78; DIN / VDE 0160/03/86; IEC 801, part 1-5; (some drafts).

Particularly fast interference pulses that are wired or also has a harmful effect on electrical input wirelessly Directions to exercise must be grasped in order to an interpretation and an analysis of countermeasures to be able to lead. The RF amplifier technology used to apply as a means of choice. Amplifiers should be high Have sensitivity to detect glitches; there  Overdrive effects occur, so that very fast pulses are falsified with high amplitudes. Also play in conventional RF amplifier technology Capacitors play a crucial role Attenuation and misjudgment are the result of one unsatisfactory measurement. In the known measurement technology can only energetic, slow impulses in the frequency domain to c. 30 megahertz can be detected or detected.

Fast faults on electrical lines or over the Air, to which the electrostatic discharge of a Person heard, are in the ultra-short frequency range wave transmitters and even above, i.e. in the frequency range of approx. 100 megahertz. The terms are slow and fast So in high frequency technology only relatively in this Connection meant. Conventional network analyzers are So too slow to recognize the fastest events to record, etc. It has often happened that a connected device the fault was not recognized and resolved has drawn, although a plant has "crashed" so to speak. The effort required in terms of shielding in the conventional RF amplifier technology has inevitably led to very expensive and unwieldy network analysis devices, their application values often fail to meet the high purchase price justify. In particular, those on the Market analyzers available only one Response behavior for pulses of approximately 1 microsecond and cannot process fast pulse packets (burst) or count and a simultaneous network short-time Do not detect interruption.

From the magazine "etz", Vol. 106 (1985), No. 9, S. 432, 433, a network analyzer is known, which in a Power grid can be plugged in. Power failure, grid voltage fluctuations, µs pulses and high frequency  Vibrations and harmonics in the power grid detected and by means of of a printer registered.

The connection and processing of the impulses is based on the conventional RF amplifier technology, which is often the mentioned oversteer effects and limited Frequency characteristics shows. The device guarantees one correct evaluation only from approx. 1 µs.

In the "Electronics Journal" 1983, Issue 10, p. 40, a small one portable network monitor described the network fault parameters automatically registered and with time provided on a built-in printer or printed out forwards a V-24 interface to other devices.

The utility model DE-GM 67 53 441 describes a Warning device for the visual and / or acoustic display of Network disturbances. The device, its housing directly into the network plug is plugged in, only detects the failure of the network or the phase on which it is operated, but no other network interference.

The invention is based on the object Network analyzer according to the preamble of claim 1 create that is inexpensive, handy and versatile and also very fast interference signals in the frequency range Can record, evaluate and save 100 MHz.

This task is characterized by the characteristics of claim 1 solved.

With the network analyzer according to the invention can also Fast pulse packets (burst) recognized and single pulses be counted from it. It is also possible on save unobserved device events as described. The speed of the device is also affected achieved that without long falsifying measuring line (Power cord) is working. The device can with a  Antennas also provide very fast operations from the air record and save as described, etc. allow the outer dimensions just because of the Simplification even within small control cabinets or devices to take measurements.

Further advantageous training are in the Unteran sayings.

An embodiment of a network analysis device according to the invention is described in FIGS . 1 to 3. It shows

Fig. 1 is a block diagram of the input circuit,

Fig. 2 different output pulses at various disorders,

Fig. 3 shows a housing example of the network analysis device.

The conversion of the interference signals or interference pulses takes place immediately after connection to the network or to the antenna. Here, "quasi-demodulation" is carried out without Derivation of HF residues; these jumps in tension The quick comparator regulates the pulse load fed, which has a fast output for the memory, which responds immediately when the comparator is triggered. Furthermore, a signal for counting, triggering etc. formed and fed to an output whose amplitude is adjustable.

The signals provide information
Amplitude height
Degree of modulation
Modulation type
Repetition frequencies u.
Energy content.

The high-frequency signals are processed indirectly to DC voltage jumps, which can be processed without expensive shielding ver, which means that the device can be kept small in space and thus also in price. State-of-the-art switching comparators and semiconductors are used in the nanosecond range. The circuit arrangement, as described in FIG. 1, results in a basic speed of over 100 megahertz, corresponding to a time of less than approx. 10 nanoseconds, so that the response and response times are at least 3 times faster than the fastest known devices in conventional HF Amplifier technology. The known devices are also not concerned with problems which can exert an influence through the air.

The diagram of FIG. 2 shows the possibility of analytical evaluation.

In Fig. 3 an embodiment of the network analysis device is shown, which is integrated in a connector housing and thereby offers the shortest connection to the network without a power cord. This embodiment already allows the connection of an antenna ( 1 ) and the connection of additional devices via the plug ( 13 and 15 ) for evaluation, triggering, counting, etc.

The current events, such as overvoltage ( 3 ), nominal voltage ( 5 ) and undervoltage ( 6 ) as well as peaks ( 7 ) and radiation ( 8 ), are displayed directly on the front by means of LEDs. In addition to the current area, the events occurring in the measurement period, such as overvoltage ( 4 ), undervoltage ( 9 ), power failure greater than 10 milliseconds ( 10 ) as well as stored peaks ( 11 ) and radiation ( 12 ), are displayed in the memory area, so that they are already in this Execution an overview of the network conditions and the "HF contamination" in the air is possible, even without additional equipment. All alarms can be deleted with a push button ( 2 ). With a toggle switch ( 14 ) and a push button ( 16 ) the device is activated for connection to a live socket for 220 volts / 50 Hz. An adjustment of the network limit values takes place via adjustment openings ( 18 ) on the side, while the adjustment of trigger and HF receiver as well as the adjustment of trigger and receiver tips takes place via the openings ( 17 ).

Adjustment and adjustment of the limit values is possible without opening the Device possible. Due to the built-in accumulator Device capable of alarms or set memory to about 4 hours after a power failure bridge. Even a prolonged power failure remains after discharge of the accumulator with recurring mains "quasi infinite" saved until reactivated the device.

Claims (7)

1. Network analyzer for the indication, analysis, registration, storage and reporting of electromagnetic disturbances in an optical, acoustic or other way, with an input circuit which converts the electrical interference signals or interference pulses into electrically more usable quantities, characterized in that
that the input circuit contains a comparator (K) switching in the nanosecond range, one input ( 3 ) of which the signals to be analyzed are supplied via diodes which also switch in the nanosecond range and a sensitivity adjuster, the two tem input ( 2 ) of which a variable threshold voltage is supplied, and the latter Output ( 6 ) gives pulses ( Fig. 2a to 2e) to the evaluating or storing circuit parts, the duration of which corresponds approximately to the energy content of the interference signals,
and that the network analyzer is accommodated in a housing which can be plugged directly into the mains socket. 2. Network analyzer according to claim 1, characterized in that wirelessly transmitted interference signals can be detected via an antenna connection ( 1 ). 3. Network analyzer according to claim 1 or 2, characterized in that on the front of the housing optical display elements for voltage peaks ( 7 ), interference radiation ( 8 ) and Netznom- ( 5 ), Netz- over ( 3 ) and Netzunterspension ( 6 ) are provided. 4. Network analyzer according to claim 3, characterized in that in addition to these current display elements store de, optical display elements for voltage peaks ( 11 ), interference radiation ( 12 ), overvoltage ( 4 ), undervoltage ( 9 ) and power failure ( 10 ) are provided. 5. Network analyzer according to one of the preceding claims, characterized, that the network analyzer on acoustic reporting elements points. 6. Network analyzer according to one of the preceding claims, characterized in that the housing has output connections ( 13, 15 ) via which the processed interference signals other evaluation devices (counters, oscillographs) can be fed. 7. Network analyzer according to one of the preceding claims, characterized, that the network analyzer has an accumulator that this ver after a power failure for a long time ensures and maintains the stored data.