DE2631509B2 - Procedure for the automatic checking of meters - Google Patents

Description

The invention relates to a method for the automatic checking of meters that the Measurement of consumed electrical or other energy are used and a microcomputer as well as a Display device included and / or additional devices included in such meters, ζ. Β. Maximum works, with a microcomputer, a display device and a non-volatile memory. Of the Non-volatile memory is used to store all data that must not be lost in the event of a power failure.

The utility companies expect such energy meters to function reliably over several Decades. For such long periods of time, when using modern technologies, e.g. B. the MOS technology, in which large sound circuits customary today are predominantly carried out, e.g. No reliability values yet before. Due to the complicated structure, the number of possible causes of failure is large, with some errors occur only intermittently and / or depending on certain temperature ranges.

The invention is therefore based on the task of providing a means of testing in good time To create detection of defective electronic equipment in such meters. Becomes a non-volatile If the memory is used and the error is not in this memory, it is advantageous if the memory contained there Data are retained so that they can be evaluated despite a device failure.

This object is achieved by the invention presented in the characterizing part of claim 1.

The energy meters or parts of these meters are controlled by a microcomputer whose program is contained in a read-only memory. The read-only memory takes on a test program that is either integrated with the normal program or saved additionally. Through this test program the microcomputer itself as well as all detectable ones become at sufficient intervals Equipment of the device checked. The test program is preferably triggered by a mostly already existing time base, the z. B. with maximum counters the definition of the measurement period serves to control. If there is no time base, such meters are usually available at a network frequency Available from which a time base can be derived or it is, if no network connection is available, such. B. in heat meters, a built-in free-running oscillator is used.

If the test program detects an error, an optical or some other suitable one is initially required Switch on fault display. This fault display is either permanently switched on or it is only visible during an interrogation or reading. Depending on the type of error and the structure of the test program is over To decide what to do next: in the event of minor errors, the device can work properly in individual parts continue to function; In the event of serious errors, the computer expediently takes over the further data processing a.

To check any non-volatile semiconductor memory that may be present, e.g. B. a MNOS memory, special measures must be taken to take account of the nature of this storage tank. Such Memories only allow a limited number of write cycles and take a relatively long time before each If the write process takes a long time, an erase operation that takes, for example, one second. The saved Information from such a non-volatile semiconductor memory must always be provided at sufficient intervals be refreshed again. The use of well-known

The usual test methods for storage tanks are not possible or not practical due to the properties mentioned.

For this reason, every time the computer reads a value in the non-volatile memory has registered, this is checked again and compares it with the registered value. A However, a large part of the memory content is only very rarely or only at all when it is refreshed re-enrolled. An error that now occurs in such a rarely used part of the memory occurred would not be recognized until the next refresh cycle. This defect is Basically unrecoverable without reducing the useful life of this memory. The number of the additional read operations is, however, several orders of magnitude higher, so that it is fundamentally As long as the mains supply is available, all data stored in the non-volatile memory is possible also run in the computer's memory; this is the correspondence at shorter intervals of the two memory contents can be checked.

The main task of the non-volatile memory is to save all data in the event of a mains voltage failure Network recovery are required. For this purpose, a write operation is normally carried out when a power failure is detected carried out. Sufficient energy must be stored in the power supply section of the meter to power it to enable the computer to read out the data again after it has been registered and to check that it is correct in order to be able to trigger the error message if an error is detected before the The electronics supply voltage breaks down. Due to its nature, the fault message can only be in one non-volatile storage element are retained.

It is therefore generally registered by writing in the non-volatile memory. In the case, that the error message should also be retained in the event of a defect in this memory is an additional one Storage element, e.g. B. a bistable relay to be provided.

For the memory test in general, so-called

"Walking bit patterns" in use. Here will be

ι »all locations of a memory occupied by a test bit pattern in cyclical order. This procedure is also at the refresh of the non-volatile memory applicable, so that after a few refresh cycles every stored value has occupied every available memory location once. This procedure is particularly useful if z. B. one of the stored numerical values is mainly used for control purposes. In an electronic maximum counter z. B. those supplied by the kilowatt hour meter Consumption-proportional pulses from the microcomputer summed up and shown on the existing display device shown in the form of a kilowatt hour display. If the kilowatt hour meter has its own kilowatt hour display, so the comparison of both counter

2> would provide information about the correct function of the Maximumwerk. In the event of a power failure, the current status of the electronic kilowatt-hour counter is stored in the Inscribed non-volatile memory. If a defect occurs in just one memory location, it will be

jo with cyclical allocation of the memory locations express some time in it that the two kilowatt hour displays no longer match.

Claims (9)

Patent claims: 1. Procedure for the automatic verification of meters that measure the amount of electrical consumed or other energy and which contain a microcomputer and a display device and / or additional devices contained in such meters with a microcomputer, a display device and a non-volatile memory, characterized in that the microcomputer's read-only memory contains a test program through which sufficient, automatically or by external commands controlled intervals of the microcomputers and / or all detectable devices of the electronic meter are checked, that also upon detection of a Error this is reported and the further data processing and registration is blocked that the numerical values calculated up to the occurrence or detection of an error before the final Blocking the counter to be written into the non-volatile memory and that for Check the non-volatile memory of the computer after each write a read triggers, compares the two values and each memory location once in a recurring cycle is occupied by a character. 2. Arrangement for the method according to claim 1, characterized by such a large buffering Power supply of the electronic part of the energy meter that a safe takeover of the Data in the non-volatile memory must be guaranteed in the event of a failure of the external power supply. 3. Arrangement for the method according to claim 1 and 2, characterized in that a detected Error initiates the immediate writing of the data to be saved in the non-volatile memory. 4. Arrangement for the method according to claim 1 to 3, characterized in that a detected error is displayed optically. 5. Arrangement for the method according to claim 1 to 4, characterized in that a detected error on the existing display device is shown. 6. Arrangement for the method according to claim 1 to 5, characterized in that a detected error by flashing all digits of the existing Display device is displayed. 7. Arrangement for the method according to claim 1 to 6, characterized in that a detected error on the existing display device in Displayed in the form of a message made up of alphanumeric characters. 8. Arrangement zi. »M method according to claim 1 to 7, characterized in that after an error has been detected, the further display of values on the existing display device is prevented. 9. Arrangement for the method according to claim 1 to 8, characterized in that to check the non-volatile memory in this by the Microcomputer test words are written in, then read out and compared with the nominal value will.