JPH09212787A - Intelligent transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the production processes and to reduce the manufacturing cost by providing a data collecting mode where sensor outputs are continuously sampled in addition to a normal mode. SOLUTION: MPU 3 is operated by the data collecting mode program of ROM 4 in a data collecting mode. In the data collecting mode, the outputs of the sensor 1 are normally continuously measured by a prescribed sequence by changing the gain of the amplifier of an input circuit. Digital communication by an exclusive command is enabled. In this case, the program for realizing the operation mode of the normal mode/data collecting mode is stored in ROM 4. An operation mode flag indicating the operation mode of a transmitter is stored in a prescribed address of EEPROM 5 as previously fixed data in order to select and use the program. Then, MPU 3 refers to the operation mode flag to start the normal mode program or the data collecting mode program in a processing at the time of resetting.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD This invention relates to intelligent transmitters.

[0002]

2. Description of the Related Art Conventionally, an intelligent transmitter has only the normal mode as a transmitter for converting a process variable into an analog current signal of 4 to 20 mA and transmitting it. Thus, for example, in the state where the correction data has not been written to the electrically erasable programmable read-only memory, the transmitter cannot operate normally because there is no correction data necessary to operate in the normal mode. There wasn't.

This is particularly the case in the transmitter manufacturing process, in which only the hardware and operating program are present, ie, the correction data is electrically erasable and the programmable read-only memory in which the assembly of the hardware is completed. The state that is not written in indicates that the transmitter is in an abnormal operation. In the production process, the process of changing the temperature and the input pressure conditions and measuring the input / output characteristics of the sensor including the characteristics of the input circuit is called the temperature characteristic measuring step. The correction data is created by the production computer using the learning data measured in this step. Conventionally, in the temperature characteristic measurement process, a jig for temperature characteristic measurement was attached to the sensor and the input circuit, and an interface for data collection was required between the production computer and the production computer. Further, in the temperature characteristic confirmation step after the temperature characteristic measurement step, the temperature and applied pressure of the normally operating transmitter are changed by referring to the correction data written in the electrically erasable programmable read-only memory, Check the input / output characteristics of the transmitter. In this process, it was necessary to attach a temperature characteristic checking jig for normal operation as a transmitter to the sensor and the input circuit and measure the output current.

[0004]

In the above-mentioned prior art, since the transmitter normally operates only after the correction data is written in the electrically erasable programmable read-only memory, the temperature characteristic measuring step is performed before the temperature characteristic measuring step. There is a problem that it is difficult to confirm the operation of the hardware. Further, in the production process, it is necessary to write correction data and replace the jig between the temperature characteristic measurement process and the temperature characteristic confirmation process, and automation from the temperature characteristic measurement process to the temperature characteristic confirmation process is difficult. There was a problem. In addition, if some or all of the correction data of the transmitter operating at the customer is lost due to an accident of the transmitter, the transmitter will operate abnormally and it will be difficult to investigate the cause of the abnormality. There was a point.

It is an object of the present invention to facilitate verification of transmitter hardware operation in the transmitter manufacturing process, with no correction data written to the electrically erasable programmable read-only memory. Especially. Then, it is intended to automate the process from the temperature characteristic measuring step to the temperature characteristic confirming step. Further, by recording the history of the production process, it is possible to investigate the cause of the abnormality in the production stage when an abnormality occurs and to shorten the countermeasure time.

Another object of the present invention is to easily check the operation of the hardware online by using the data collection mode when the customer's operation becomes abnormal and investigate the cause of the abnormality. It is to shorten the countermeasure time.

[0007]

In order to achieve the above object, the present invention stores a program for two operation modes, a normal mode and a data acquisition mode, in a read-only memory and makes it electrically erasable programmable. A flag for selecting and using the program is provided in the read-only memory as data of a predetermined address.

In order to achieve another object, according to the present invention, the operation mode of the transmitter is changed, and the processing necessary for confirming the operation of the transmitter hardware is performed by the program of the data collection mode. The situation is digitally controlled by the host control system, handheld communication device, or
A dedicated communication command is provided to enable monitoring with a production computer.

In the intelligent transmitter according to the present invention, the data acquisition mode and the normal mode are referred to by referring to the flags of the electrically erasable programmable read-only memory at the time of power-on or software reset operation of the microprocessor. By selecting and starting a program, it is possible to operate in either the data collection mode or the normal mode. Here, as a method of selecting a program, there are a method of making two completely different programs and a method of partially changing the processing method with the same basic processing.

The dedicated communication command is a command that can be used only in the data collection mode, except for the command for changing the mode from the normal mode to the data collection mode. The dedicated communication command is created by the same protocol as the digital communication in the normal mode and can be used in the same hardware environment as the digital communication in the normal mode. Therefore, by incorporating a program that sends / receives a dedicated communication command into the host control system, handheld communication device, or production computer, the data indicating the operation status of the hardware can be read from the transmitter operating in the data collection mode. , And data setting for confirming the operation of the hardware becomes possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of an intelligent transmitter according to an embodiment of the present invention.

One or a plurality of sensors 1 is an input circuit 2
Connected to. MPU (microprocessor) 3, RO
An M (read only memory) 4, an electrically erasable programmable read only memory (hereinafter, EEPROM) 5, a random access memory (hereinafter, RAM) 6 are connected to each other by a data bus and an address bus. Also, MPU
3, the input circuit 2, the analog communication circuit 7, the digital communication circuit 8, the external zero adjustment switch 9, the digital indicator 10 is M
It is connected by a serial communication port of PU3 or an input / output control line. The analog communication circuit 7 is a two-wire transmission line 1
Connected to 1. The digital communication circuit 8 is connected to the two-wire transmission line 11 in parallel with the analog communication circuit 7.

Next, the operation of each section for each operation mode will be described. Normal mode indicates normal operation as a transmitter. In the normal mode, the MPU 3 operates according to the normal mode program stored in the ROM 4. The output of the sensor 1 which changes according to the input process variable is input through the input circuit 2 to M
The process data input to the sensor 1 is calculated by using the correction data stored in the EEPROM 5 and taken into the PU 3. MPU3 EE the calculated process variable
Processing is performed based on the output conditions such as range and damping set in PROM5, and output to the analog communication circuit 7. The analog communication circuit 7 converts the output data of the MPU 3 into analog data, converts it into a DC current signal of 4 to 20 mA, and outputs it to the two-wire transmission line 11. Thereby, the process variable is obtained as a current signal of 4 to 20 mA. The digital communication circuit 8 serves as an interface for performing digital communication with a communication device such as a host control system connected to the two-wire transmission line 11, a handheld communication device, or a production computer. The digital communication circuit 8 demodulates the signal obtained from the communication device via the two-wire transmission line 11 and sends it to the MPU 3, and also modulates the serial data sent by the MPU 3 and outputs it to the two-wire transmission line 11. To do. MPU
3 is an EEPROM 5, in response to a setting change command or data write / read command obtained via the digital communication circuit 8.
Data writing / reading to / from the RAM 6 and data reading from the ROM 4 are performed. This enables digital communication between the transmitter and the communication device connected to the two-wire transmission line 11, and enables the communication device to read output conditions, parameter settings, and process variable calculation values. The digital indicator 10 displays data according to the calculated value of the process variable. The display method can be changed from the communication device by digital communication. The external zero adjustment switch 9 is composed of two reed switches for up / down operation which are operated by a magnet. Normally, both are in the off state, and when one is turned on, the output current is increased / decreased.

In the data collection mode, the MPU 3 is a ROM
It operates with the data collection mode program of No. 4. In the data acquisition mode, the output of the sensor 1 is constantly measured in a predetermined sequence by changing the gain of the amplifier of the input circuit. The processing time for one sequence requires about 1.4 seconds. As the measurement data, the past 12 times of a series of sequences are stored in the RAM 6, and the data is updated in the oldest order. The analog communication circuit 7 outputs data of about 4.5 mA as an initial value. The analog communication circuit 7 outputs the output current to the two-wire type transmission line 11 to about 4.5.
Maintain at mA. The digital communication circuit 8 enables digital communication between the transmitter and the communication device connected to the two-wire transmission line 11 as in the normal mode. The digital indicator 10 displays the A / D converted value of the measurement data. The display change cycle is
It takes about 1.4 seconds to process one sequence. The measurement data to be displayed is the first measurement data in the sequence. The display data is for the up / down of the external zero adjustment switch 9.
Can be changed with the down switch.

In the data collection mode, digital communication by a dedicated command is possible. The measurement data is past 12 by digital communication using the sensor data collection command.
You can read batches at once. The output current value can be changed by digital communication using a constant current setting command. The changed output current value returns to the initial value of about 4.5 mA after the elapse of a predetermined fixed period. The correction data calculated by the production computer can be written to the EEPROM 5 by digital communication using the correction data write command. Further, the correction data written in the EEPROM 5 can be read by digital communication using the correction data read command. Furthermore, all the correction data written in the EEPROM5 can be cleared to off by digital communication using the correction data deletion command. The operation mode can be changed by digital communication using a data collection mode setting command and a normal mode setting command.

A program for realizing the two operation modes of the normal mode / data collection mode, which is a feature of the present invention, is stored in the ROM 4. Further, in order to select and use a program, an operation mode flag indicating an operation mode of the transmitter is stored as predetermined data at a predetermined address of the EEPROM 5. As shown in FIG. 2, the MPU 3 starts the program in the normal mode or the program in the data collection mode by referring to the operation mode flag in the process at the time of reset. For the operation mode flag, OFF is entered in the normal mode, and OFF (or data other than OFF) is entered in the data collection mode. These data are written using the normal mode setting command and the data collection mode setting command. Set by digital communication. Furthermore, even if the normal data is set, fixed data is provided near the end of the correction data to prevent abnormal operation of the normal mode when the correction data is not stored in the EEPROM5. If not set, the data collection mode is selected even if the operation mode flag is the normal mode.

Next, an embodiment will be shown in which the production process is automated by changing the operation mode in the production process. FIG. 3 shows a flow of a temperature compensation process that creates the characteristics of the transmitter. The temperature compensation step is a temperature characteristic measurement step of measuring the input / output characteristics of the sensor 1 and the input circuit 2 by changing the temperature and applied pressure, and a correction data calculation for calculating correction data using the learning data collected in the temperature characteristic step. EE of process and correction data of transmitter
It can be divided into a correction data writing process to confirm writing / reading to the PROM5, and a temperature characteristic confirmation process to confirm the input / output characteristics of the transmitter by changing the temperature and applied pressure. Conventionally, a jig corresponding to the interface for setting the gain of the A / D converter and the amplifier of the input circuit is required for the temperature characteristic measurement step, and the temperature characteristic confirmation step requires the MPU3, ROM4, EEPROM5 for operating as a transmitter. , RAM
6, a jig including the analog communication circuit 7 was required.
In addition, in the correction data writing process,
It was necessary to write correction data using a writer. As a result, in FIG. 3, the temperature characteristic measuring step, the correction data writing step, and the temperature characteristic confirming step cannot be automated because manual operations such as jig replacement and correction data writing by the ROM writer occur during the process. .

Here, by using the function of the data collection mode according to the present invention, it is possible to automate the process from the temperature characteristic measuring step to the temperature characteristic confirming step. By operating the transmitter in the assembled state, that is, the transmitter having the configuration shown in FIG. 1 in the data collection mode, the measurement data can be collected by the sensor data collection command in the temperature characteristic measurement process. After calculating the correction data in the correction data calculation step, the correction data can be written in the EEPROM 5 using the correction data write command in the correction data writing step. Further, by using the correction data read command, it can be confirmed whether the written correction data has been written correctly. Next, in the temperature characteristic confirmation step, the temperature characteristic of the transmitter can be confirmed after setting the normal mode using the normal mode setting command. As described above, from the temperature characteristic measuring step to the temperature characteristic confirming step, the hardware of the transmitter in the assembled state can be used to proceed without human labor, and automation can be performed.

FIG. 4 shows a block diagram of the temperature compensation equipment for realizing the automation of the temperature compensation process. The temperature compensating equipment includes the production computer 12 and the communication interface 1.
3, a pressure generator 14 and a constant temperature bath 15. The production computer 12 controls the temperature and applied pressure of the transmitter by the thermostatic chamber 15 and the pressure generator 14, and
Digital communication with the transmitter 16 via the communication interface 13 and measurement of the output current of the transmitter are performed. The communication interface 13 is an interface for digital communication between the production computer 12 and the transmitter 16, and at the same time, supplies power to the transmitter 16 and measures the output current of the transmitter. The temperature compensating equipment with this configuration enables automation of the temperature compensating process.

The sensor 1 and the two-wire type transmission line 11 shown in FIG.
The configuration except for is equivalent to the electric circuit portion, and it is necessary to confirm the operation of the electric circuit portion after the assembly is completed. Here, instead of the sensor 1, a dummy sensor whose output is known in advance is connected and operated in the data collection mode, whereby the operation of each block in FIG. 1 can be confirmed. Conventionally, the correction data
Since abnormal operation occurs when it is not written in EEPROM5, it is necessary to write dummy correction data to check the operation, and it took time to check the operation.

Further, the correction data write command can be used to write the production control data in the process of production into the EEPROM 5 of the transmitter operating in the data collection mode. The production control data is symbolized in advance and written in EEPROM5 at each stage of production. As a result, the production information for each transmitter can be read out from the EEPROM 5 as needed and investigated.

As described above, according to this embodiment, it is possible to automate the production process and reduce the number of production jigs.
It has the effect of reducing manufacturing costs and work defects.

Another embodiment will be described. If an abnormality occurs in the transmitter while the transmitter is actually used in the customer's plant, etc., set the transmitter in the data collection mode and check the operation of each block to determine the cause of the abnormality. It becomes easy to find out. Particularly, in the case of an abnormality such as a change in the correction data, the correction data read command allows the communication device connected to the two-wire transmission line 11 to check the correction data with the transmitter still installed. In addition, when the correction data actually changes, the two-wire transmission line 1 can be sent with the correction data write command while the transmitter is still installed.
The correction data can be written from the communication device connected to 1.

As described above, according to the present embodiment, there is an effect of investigating the cause and shortening the countermeasure time when a failure occurs in the transmitter.

[0025]

According to the present invention, in addition to the normal mode in which the transmitter operates normally, a data collection mode for continuously sampling the sensor output is provided. It is possible to automate and reduce the number of production jigs, which has the effect of reducing manufacturing costs and work defects.

In addition, when a failure occurs in the transmitter being used at the customer's plant, etc., the operation of each block of the transmitter can be confirmed in the installed state by using the data collection mode. It has the effect of shortening the investigation and countermeasure time.

[Brief description of drawings]

FIG. 1 is a block diagram of a two-wire transmitter.

FIG. 2 is a flowchart of a reset operation.

FIG. 3 is a flowchart of a temperature compensation process.

FIG. 4 is a block diagram of temperature compensation equipment.

[Explanation of symbols]

1 ... Sensor, 2 ... Input circuit, 3 ... Microprocessor,
4 ... ROM, 5 ... EEPROM, 6 ... RAM, 7 ... Analog communication circuit, 8 ... Digital communication circuit, 9 ... External zero-adjustment switch, 10 ... Digital indicator, 11 ... Two-wire transmission line, 16
… Intelligent transmitter.

Front page continuation (72) Nobuaki Seta Inventor Nobuaki Seta 832 Nagakubo, Horiguchi, Hitachinaka City, Ibaraki 2 Inside Hitachi Measurement Engineering Co., Ltd. (72) Teruo Kobayashi 882, Ichige, Hitachinaka City, Ibaraki Hitachi, Ltd. Within the business unit (72) Inventor Norito Okabe 882 Ichige, Ita, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Measuring Instruments Business Unit

Claims (8)

[Claims] 1. A sensor for converting a process variable into an analog signal, an input circuit for amplifying the analog signal of the sensor and converting it into digital data, and a signal processing means for processing the digital data to convert it into an analog signal. An analog communication circuit for converting the output digital data of the signal processing means into an analog signal and transmitting the analog signal as a change in the direct current of the transmission line; and an analog communication circuit provided alongside the analog communication circuit by the signal processing means via the transmission line. A digital communication circuit for transmitting and receiving digital signals, and a digital indicator for displaying the output digital data and the operating state of the transmitter are provided, the signal processing means is a microprocessor, and each is connected to the microprocessor by a bus. 1
In an intelligent transmitter including one or more read-only memories, electrically erasable programmable read-only memory and random access memory, sensors, inputs stored in the electrically erasable programmable read-only memory Circuit, analog communication circuit corrective calculation based on the correction data and output the process variable, and when the correction data is not set, the sensor output is continuously sampled according to a predetermined sequence. An intelligent transmitter having two operation modes of a data acquisition mode to be performed. 2. The two operation modes according to claim 1, wherein the two operation modes are stored in a read-only memory with reference to data at a predetermined address in the electrically erasable programmable read-only memory. Intelligent transmitter that selects and uses programs for normal mode and data acquisition mode. 3. The intelligent transmitter according to claim 2, wherein data of a preset address in the electrically erasable programmable read-only memory is changed by digital communication. 4. The intelligent transmitter according to claim 2, wherein, in the data collection mode, the collected A / D converted data of the sensor output is transferred by digital communication to a communication device connected to a two-wire transmission line. 5. The program according to claim 4, wherein correction data calculated by a production computer using the A / D conversion data of the collected sensor in the data collection mode is electrically erasable by digital communication. An intelligent transmitter capable of writing to a read-only memory and reading the written correction data by digital communication. 6. The intelligent transmission according to claim 2, wherein in the data collection mode, a preset constant direct current is output to the two-wire transmission line, and the output current value can be changed by digital communication. vessel. 7. The intelligent transmitter according to claim 2, wherein in the data collection mode, the A / D conversion data of the sensor output collected is displayed on the digital indicator. 8. The method according to claim 2, wherein in the data collection mode, production process data is written to the electrically erasable programmable read-only memory based on an instruction by digital communication, and the written data is digital. Intelligent transmitter that can be read by communication.