JP2523053B2 - Rewriting method of EEPROM in industrial instrument - Google Patents

Description

The present invention relates to an EPROM rewriting method in an industrial instrument equipped with an electrically writable / erasable EEPROM.

[Prior Art] Conventionally, a program is stored in addition to the CPU in the differential pressure / pressure transmitter that detects the pressure of gas in the pipes installed in factories and sends this data to the receiving device. ROM that stores measurement data, calculation data, etc., PR that stores sensor characteristic data (characterization data), etc.
It is equipped with an EEPROM that stores configuration data composed of OM, correction data, data that specifies the mode, operating environment, etc.

When the CPU inputs a data signal such as the differential pressure from the sensor, it performs data conversion processing such as correcting the data from the sensor based on the characteristic data and configuration data of this sensor, and the converted output data Is transmitted to the receiving device. EEPROM
A program for rewriting the contents of is stored in the ROM, and in order to prevent the contents from being rewritten carelessly, the contents are rewritten by any of the following methods. That is, the first method is a method of rewriting after confirming whether or not rewriting can be performed by a communication command transmitted from an external device, and the second method is to make the switch rewritable by an external switch operation. This is a method of rewriting after detecting whether there is any. Furthermore, the third
The above method is a method of rewriting by a combination of the above two methods, and the contents of the EEPROM are rewritten by any of these three methods.

[Problems to be Solved by the Invention] The conventional differential pressure / pressure transmitter described above has an EEPROM in the ROM.
Since the program that rewrites the contents of is stored, if the CPU that reads and executes this program runs away due to external noise, etc., the configuration data stored in the EEPROM may be destroyed.
Even if the CPU is normally restarted after resetting, output data conversion processing is performed based on the destroyed data, and as a result, incorrect data is transmitted to the receiving device.

[Means for Solving the Problem] In order to solve such a problem, the rewriting method of the EEPROM in the industrial instrument of the present invention is an industrial method in which a program necessary for erasing or rewriting the contents of the EEPROM is received from an external device. Equipped with a transfer means for transferring to the RAM in the instrument and an erasing means for erasing the program stored in the RAM after the contents of the EEPROM are erased or rewritten by executing the program transferred to and stored in the RAM It is a thing.

[Operation] The program necessary for erasing or rewriting the EPROM contents is transferred to the RAM in the industrial instrument, and the EEPROM contents are erased or rewritten by executing this program.
This program is erased after this rewriting is completed.

EXAMPLES Next, the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of a system to which the EEPROM rewriting method in the industrial instrument of the present invention is applied.

In the figure, 1 is a differential pressure / pressure transmitter (industrial instrument),
2 is a portable communication device, 3 is a receiving instrument, 4 is a junction box, 5 is a 4-20 mA transmission line for data transmission between the transmitter 1 and the receiving instrument 3, and E is supplied to the transmitter 1. Power source.

That is, when the power source E is supplied, the oscillator 1 detects the pressure of gas or the like in the pipes installed in the factory with a sensor, corrects the detected data, etc., and corrects the corrected data. Is transmitted to the receiving instrument 3 via the 4-20 mA transmission line 5.

Next, FIG. 2 is a detailed block diagram of the oscillator 1. In the figure, 10 is a differential pressure sensor, 11 is a static pressure sensor,
12 is a temperature sensor, 13 is a multiplexer, 14 is an A / D converter, 15 is a CPU that executes programs stored in ROM and RAM described later, 16 is a digital I / O block, and 17 is a D / A converter. , 18 are EEPR, which will be described later, in addition to programs that perform normal processing.
ROM that stores the program that reads the data in the OM, the program that erases and writes the contents of the EEPROM to the RAM described later, and the program that erases the program transferred to the RAM, 19 is the differential pressure sensor 1
0 is a PROM that stores sensor characteristic data, 20 is a RAM that stores a program that writes and erases measurement data, calculation result data, and other data that is stored in an EEPROM described later. The correction data called correction data and the data for specifying the mode, operating environment, etc. are stored in the EEPROM, and Q is a transistor.

Then, the detection outputs of the differential pressure sensor 10, the static pressure sensor 11, the temperature sensor 12, etc. that detect the pressure, temperature, etc. of the gas in the pipes are sent to the A / D converter 14 via the multiplexer 13, where Converted to digital data. The CPU 15 inputs this digital data, corrects the digital data based on the characteristic data of various sensors in the PROM 19 and the configuration data in the EEPROM, and the D / A converter 17
To convert to an analog signal. Furthermore, this D /
The analog signal output from the A converter 17 is converted into an analog current signal of 4 to 20 mA by the transistor Q, and 4
It is transmitted to the receiving instrument 3 via the -20 mA transmission line 5.

It should be noted that the CPU 15 starts execution from the program at the head address of the ROM 18 when the power E is supplied and the reset is released prior to the above processing. Then, at this time, for example, when a command for rewriting the contents of the EEPROM from the portable communication device 2 is received and further program data following this command is received, this is stored in a predetermined area in the RAM 20.

After that, the CPU 15 reads the program stored in the RAM 20 and executes it, and as a result, stores predetermined configuration data in the EEPROM 21. In this way, after the configuration data is stored, the CPU 15 executes the program of the ROM 18 again to erase the program data stored in the predetermined area of the RAM 20, and at the same time, performs the above-mentioned processing, that is, inputs data from various sensors. The input data is subjected to a data conversion process in which a correction based on the configuration data or the like read out from the EEPROM 21 is performed, and the converted data is transmitted to the receiving instrument 3 via the 4-20 mA transmission line 5.

Next, FIG. 3 is a flow chart for explaining the operation of the EEPROM rewriting method in the industrial measuring instrument of the present invention.

As mentioned above, when power is supplied to the CPU15,
Alternatively, when the CPU 15 goes out of control and is reset and then reset is released, the CPU 15 executes the process from the start address of the program in the ROM 18. Then, in step 50, it is determined that the EEPROM rewrite command from the portable communication device 2 is received, and if this is not received and it is determined as “N”,
Other processing, that is, processing based on a predetermined processing program is executed and the processing is ended.

If the EEPROM rewrite command can be received and it is determined to be "Y" in step 50, the rewrite program data following this rewrite command is received and loaded (transferred) to the RAM 20 in step 52. And step 5
The program loaded into RAM20 is read out and executed in step 3, the data in EEPROM21 is rewritten, and this rewriting ends. In step 54, execute the program in ROM18 to R
Erase the program data loaded in AM20 and exit.

As described above, the present invention rewrites the contents of the EEPROM 21 with the program loaded on the RAM 20 and erases the loaded program after the rewriting is completed. As a result, even if the CPU 15 runs out of control due to external noise or the like, the program that rewrites the contents of the EEPROM is already deleted and does not exist in the RAM 20, so the contents of the EEPROM are not rewritten and the contents are retained.
When restarting after a runaway of 5, this retained E
Since the processing is performed based on the EPROM configuration data, accurate data can be transmitted to the receiving instrument 3.

In the present embodiment, the example in which the EEPROM 21 in which the contents of the configuration data are held when the CPU 15 runs out of control is applied to the differential pressure / pressure transmitter 1 has been described, but the present invention is not limited to this and is used on site. It can be widely applied to various thermometers and electromagnetic flow meters used.

[Effects of the Invention] As described above, the EEPROM in the industrial instrument of the present invention
The rewriting method is configured so that the program necessary for erasing or rewriting the EPROM content is transferred to the RAM in the industrial instrument, and the program is erased after the EEPROM content is erased or rewritten by the execution of this program. Therefore, even if the CPU runs away due to external noise, RAM
Since the program that rewrites the contents of the EEPROM has already been erased, there is no risk that the contents of the EEPROM will be accidentally rewritten, so the contents are retained, and as a result, the CP
When U restarts, processing is performed based on the held contents, and there is an effect that accurate data can be transmitted to the receiving device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus to which the EEPROM rewriting method in an industrial instrument of the present invention is applied, FIG. 2 is a block diagram of a system to which this method is applied, and FIG. 3 shows the operation of this apparatus. It is a flowchart explaining. 1 ... Transmitter, 2 ... Portable communication device, 3 ... Receiving instrument,
5 ... 4-20mA transmission line, 10 ... Differential pressure sensor, 11 ... Static pressure sensor, 12 ... Temperature sensor, 13 ... Multiplexer, 14
…… A / D converter, 15 …… CPU, 17 …… D / A converter, 18 …… R
OM, 19 ... PROM, 20 ... RAM, 21 ... EEPROM, Q ... transistor.

Claims (1)

(57) [Claims] 1. An electrically erasable and erasable EEPROM for storing correction data and configuration data such as data designating a mode and operating environment, and correction of detection data based on the configuration data. In the rewriting method of the EEPROM in the industrial instrument to perform, transfer means for receiving a program necessary for erasing or rewriting the contents of the EEPROM and transferring to the RAM in the industrial instrument, the stored in the RAM in the industrial instrument Rewriting of the EEPROM in the industrial measuring instrument, comprising: erasing means for erasing the program stored in the RAM in the industrial measuring instrument after the content of the EEPROM is erased or rewritten by executing the program. method.