JPH0477039A - Communication equipment - Google Patents

Abstract

PURPOSE:To prevent malfunction by automatically detecting the connection state, inquiring a transmitter about an equipment name, reading a program corresponding to an equipment from a 2nd storage area and operating the equipment. CONSTITUTION:When a connection line 4 of a communication equipment 3 connects to an output signal line 2, an output current I of a transmitter 1 flows through a resistor 21 and a voltage across the resistor 21 is higher than a voltage of a reference power supply 22 and a comparator 23 outputs a connection detection signal. An interrupt input enters a CPU 12 by the signal and gives an inquiry command of an equipment name to the transmitter 1 at first and the equipment name sent from the transmitter 1 is received. Then a head address of a fixed part to the equipment name is set to an address designation register 13. Then the program specific to the equipment is read from an address designated by the address designation register 13 by the program memory 14 to execute the processing specific to the equipment.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to a communication device that connects to the output signal line of various transmitters such as an electromagnetic flowmeter, temperature converter, and pressure transmitter to perform data communication. .

(B) Conventional technology Conventionally, a communication device is connected to the output signal line of various transmitters, and the communication device sets and changes the operating conditions on the transmitter side, as well as monitors the data sent from the transmitter. There is.

(c) Problems to be solved by the invention If the transmitter has a different type of transmitter, such as an electromagnetic flowmeter, temperature converter, or pressure transmitter, etc., the data to be set for each transmitter may be different. Because the types of transmitters are different, it is necessary to prepare separate programs for each of the two transmitters in the communication device.

Since this type of communication device is portable and the processing content itself is relatively simple, an 8-bit CPU is usually used. However, since 8-bit CPUs usually do not have a memory space of 64, there are problems in that the number of connected models cannot be increased or that the ROM must be replaced.

Additionally, if you connect to one transmitter and start communication, and then connect it to another transmitter, the communication W device itself will
If you do not know this and continue to operate, the communication device will operate as if the previously connected transmitter is still connected, which may lead to completely incorrect operation and may cause an accident. Ta.

The present invention has been made in view of the above problems, and provides a communication device that can be connected to many transmitters even if the communication device has a small memory space and CP[J, and is less likely to malfunction when changing connections. It is intended to.

(d) Means and operation for solving the problems The communication device of the present invention can be optionally connected to the output signal line of various transmitters.
A device that communicates with a transmitter includes a first storage area that stores programs common to various types of transmitters, a second storage area that separately stores programs specific to each transmitter, and The apparatus includes a connection detection means for detecting the presence or absence of connection to an output signal, and a means for transmitting a command to inquire about the device name to the connected transmitter each time the connection detection means detects the connection, and Two different programs are read from the second storage area and operated for each transmitter depending on the device name.

In this communication device, when connected to the output signal line of the transmitter, the connection detection means automatically detects the connection state, queries the transmitter for the device name, and then outputs the ON from the second storage area. B↓ Read and operate the corresponding program. From these two points, it becomes possible to access a memory amount that exceeds the CPL○ memory space. Furthermore, even if the type of connected transmitter is changed during the process, the device name is queried at reconnection time and the program corresponding to the device name is run, so malfunctions can be prevented.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, a connection line 4 of a communication device 3 is connected to an output signal line 2 of a transmitter 1. Note that 5 is a load resistance and 6 is a power supply. An output type current of -4 to 20 mA flows through the output signal line 2.

The communication device 3 includes a connection detection unit 11. It includes a CPU 12, an address designation register 13, a program memory 14, a keyboard 15, a display section 16, and gates 17, ]8.

Output signal line 2 of transmitter 1 is connection line 4, gate 17.18
It is connected to the CPU 12 via. Connection detection unit 11
is composed of a resistor 21 through which the output type /lLr of the transmitter 1 flows, a reference voltage #22, and a comparator 23. When the connection line 4 of the communication device 3 is connected to the output signal line 2, a current flows through the resistor 21, and the voltage across the resistor 2I becomes the reference power supply 2.
2, the output of comparator 23 becomes
“The signal becomes hyper and a signal indicating that the communication device 3 is connected to the output signal line 2 is applied to the interrupt input terminal of the CPU 12.

The memory configuration of the communication device 3 is shown in FIG.

The CPU 12 includes a memory having an area for storing programs for common parts and an area for storing programs for transmitter-specific parts. The program memory 14 is
It has an area larger than the internal memory storage area of the CPU 12, and the first 8 sections are written with programs related to processing common to each model, and after that, blocks of parts specific to each device are written for each device. The first address of the device-specific part is address 1, 2, 3, etc., respectively.
is predetermined. CPU by writing the start address of the device part into the address specification register 13.

12 accesses the device-specific portion of its own memory area, the program area of the corresponding device in the program memory 14 is accessed.

For example, write address 1, which is the start address of the unique area of address specification Renosk I3, and device 1, and
When UI 2 accesses the device specific area, the contents of the device 1 specific area are read out, and when address 2, which is the start address of the device 2 specific area, is written, the contents of the device 2 specific area are read and executed. will be done.

FIG. 3 shows a connection configuration between the CPU I 2, the address designating register 3, and the program memory 14. CPU1
2 accesses the common part, the common part of the program memory 14 is sent as is to the CPU 2, but when accessing the unique part, the program memory 1
The corresponding portion on 4 is sent to the data bus of CPU 12.

In the embodiment device configured as described above, when the communication device 3 is not connected to the output signal line 2 of the transmitter 1, the current r does not flow through the resistor 21, so the comparator 23
is a "'O°" output, that is, it does not output a connection detection signal, and therefore the CPU 2 does not execute an interrupt operation.

When the connection line 4 of the communication device 3 is connected to the output signal line 2,
The output current ■ of the transmitter 1 flows through the resistor 21, so the voltage across the resistor 21 becomes higher than the voltage of the reference power supply 22, and the comparator 23 outputs the signal "1°", that is, the connection detection signal.This signal As a result, an interrupt input is input to the CPU 2, and as shown in the flowchart of FIG. Receive it (step 5T2).Then, set the start address of the unique part for the device name in the address specification register 13 (step 5T3).Next, program memory 1
4, the MAL-specific program is read from the address specified by the address designation register 13, and device-specific processing is executed (step 5T4). Note that the interrupt processing shown in FIG. 4 is executed when the connection line 4 of the communication device 3 is connected. For example, if the connection line 4 is disconnected from the output signal line 2 of the transmitter 1 and then reconnected, the device name of the transmitter is queried and the specific processing corresponding to the device name is executed again. Therefore, malfunctions due to different device names will not occur. Even if the connection line 4 is connected from one device to another type of device, the device name is always queried and the unique part reads and executes the content corresponding to the device name, so malfunctions will not occur.

(f) Effects of the Invention According to the present invention, the first storage area stores a program common to various transmitters, the second storage area separately stores a program specific to each transmitter, and the connection detection means for detecting whether or not the device is connected to the 8-power signal; and means for transmitting a command to the connected transmitter to inquire about the name of the pair'-R device each time a connection is detected based on the connection detection signal. A program that is different for each transmitter is read out from the second storage area and operated according to the device name read from the transmitter, so a large memory area can be used by a CPU with a small memory area. , it becomes possible to connect various transmitters with a single communication device without replacing the program memory. In addition, the connection to the transmitter is constantly monitored, and if the connection is disconnected and then reconnected, the device is inquired and the program is switched to the compatible model before operation is performed. There is no need to reset each time, and there is no need to worry about malfunctions when changing connections.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a communication device showing an embodiment of the present invention, FIG. 2 is a diagram showing a memory configuration of the communication device, and FIG.
The figure is a block diagram showing the connections between the communication device 1: the CPU, the program memory, and the address designation system 7. FIG. 4 is a flow diagram showing the h slipping process of the communication device. 1: Transmitter, 2. Output wire, 3: Communication device, 11: Connection detection unit, 12: CPU,
13 Niprogram memory. Patent applicant Shima Ritsu Seisakusho Co., Ltd. Agent
Patent Attorney Shigeru Nakamura

Claims (1)

[Claims] (1) In a communication device that is optionally connected to the output signal line of various transmitters and communicates with the transmitter, there is a first storage area that stores a common program for various transmitters, and a first storage area that stores a program common to each transmitter. a second storage area for separately storing programs; a connection detection means for detecting the presence or absence of connection to the output signal of the transmitter; and a device name for the connected transmitter each time the connection detection means detects a connection. By reading a different program for each transmitter from the second storage area and operating it according to the device name read from the transmitter, it is possible to connect to many types of transmitters. communication equipment.