JPS622685Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mutual monitoring device for microcomputers in which, when a plurality of microcomputers are used, each microcomputer monitors abnormalities in the microcomputers to be monitored.

Conventionally, when a device using a microcomputer is constructed and the device is operated using the microcomputer, abnormalities may suddenly occur in the microcomputer for various reasons, causing the microcomputer to malfunction. Therefore,
In order to prevent such malfunctions, a reset circuit has been provided that detects the abnormality when it occurs in the microcomputer, returns the microcomputer to its initial state, and restarts the microcomputer. In such a case, it was necessary to separately provide an external circuit for resetting the microcomputer. Furthermore, there are cases where two microcomputers are used to diagnose abnormalities in the other microcomputer, but in this case, the diagnostic signal from the microcomputer is input to the interrupt terminal of the other microcomputer. , interrupts the other party's microcomputer, counts the interrupt interval using a timer, etc., determines that an abnormality has occurred when the interrupt interval deviates from a preset value, and interrupts the other party's microcomputer. Therefore, an interrupt terminal was used to input a reset signal to the microcomputer that was to be reset, that is, the microcomputer that had malfunctioned.

The present invention was devised in consideration of the above points, and its purpose is to provide a highly reliable mutual monitoring device for microcomputers to prevent malfunctions of microcomputers, without using interrupts, and with an extremely simple configuration. Our goal is to provide the following.

Hereinafter, an embodiment based on the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block circuit diagram of an embodiment of a mutual monitoring device for microcomputers according to the present invention. In order to simplify the explanation of the present invention, the following embodiments will be described using two microcomputers.

In FIG. 1, 10 is a first microcomputer, and this microcomputer 10 has normal output ports 11 and 13, and a normal input port 12.
It also has a reset terminal 14. 20 is a second microcomputer, and this microcomputer 20 also has normal output ports 21, 2.
3. A conventional input port 22 and reset terminal 24 are provided. 25 is an alarm circuit. Now, when the microcomputer 20 monitors an abnormality in the microcomputer 10, the output port 11 of the microcomputer 10 sends a diagnostic signal, for example, a pulse example that repeats high and low levels at a constant cycle, to the microcomputer 2.
0 input port 22. When an abnormality occurs in the microcomputer 10 and the diagnostic signal of the above-mentioned pulse train with a constant period loses the regularity of repeating high level or low level and is disturbed, the microcomputer 20 detects this disturbance and
Microcomputer 1 from its output port 23
Microcomputer 1 is connected to reset terminal 14 of
It outputs a reset signal of 0 and also outputs an alarm signal for issuing an alarm to the alarm circuit 25. Alternatively, when the microcomputer 10 monitors the abnormality of the microcomputer 20,
The above-mentioned diagnostic signal is input from the output port 21 of the microcomputer 20 to the input port 12 of the microcomputer 10 at regular intervals.
When an abnormality occurs in the microcomputer 20, the microcomputer 10 detects a disturbance in the regular diagnostic signal and outputs a reset signal for the microcomputer 20 from its output port 13 to the reset terminal 24 of the microcomputer 20. The alarm signal is output to the alarm circuit 25 in the same manner as described above.

The operation of the above configuration will be described below.
Here, a case will be described in which the microcomputer 20 monitors an abnormality in the microcomputer 10. Currently, microcomputers 10, 20
is in operation, the time for one loop of the program of the microcomputer 10 is set as _T1 , and the diagnostic signal outputted from the output port 11 of the microcomputer 10 is a repeating pulse train signal of high level and low level for each loop. This is period 2
This pulse train signal with a period of 2T ₁ , that is, the diagnostic signal _, is sent to the microcomputer 2.
0 input port 22. The microcomputer 20 takes in this diagnostic signal every loop time _T1 of the program of the microcomputer 10. At this time, if the microcomputer 10 operates normally and a diagnostic signal is inputted to the input port 22 of the microcomputer 20 at regular intervals of _2T1 , the microcomputer 2
The regularly fixed periodic diagnostic signal taken in as 0 becomes a repeating signal of high level and low level output from the output port 11. In this case, the comparison data set in advance in the microcomputer 20 and the diagnostic signal taken into the microcomputer 20 match, and a reset signal for resetting the microcomputer 10 and an alarm circuit are output from the output port 23 of the microcomputer 20. The microcomputer 10 continues to operate normally without outputting an alarm signal for activation.

Next, if the program or software of the microcomputer 10 goes out of control and does not run a normal program, that is, does not execute a predetermined routine, the microcomputer 10
The diagnostic signal output from the output port 11 is no longer a regular repeating pulse train signal of high level and low level, and an abnormality occurs in the period _2T1 . Therefore, this diagnostic signal taken in by the microcomputer 20 is different from the diagnostic signal that the microcomputer 10 outputs when it is normal.
The microcomputer 20 compares preset comparison data with this diagnostic signal at the time of occurrence of an abnormality to detect the occurrence of an abnormality. When the repetitive pulse train signal that is input to the microcomputer 20 continues to be at a high level 10 times in a row or a low level 10 times in a row, the microcomputer 20 determines that an abnormality has occurred in the microcomputer 10 and detects the occurrence of an abnormality in the microcomputer 10. When the microcomputer 20 detects this, the microcomputer 20 outputs a reset signal from its output port 23 to the reset terminal 14 of the microcomputer 10 to reset the microcomputer 10, and outputs an alarm signal from the output port 23 to the alarm circuit 25 to reset the alarm circuit. For example, L, E, and D (not shown) are activated to issue an alarm. Note that the above-described determination of the occurrence of an abnormality in the pulse train signal can be determined arbitrarily. Further, when the microcomputer 10 monitors the microcomputer 20, it can be done in the same manner as in the embodiment described above. In this case, one loop time of the diagnostic signal is shown as T ₂ in FIG. Furthermore, in the embodiment described above, 2
However, when three or more microcomputers are used, multiple microcomputers other than the microcomputer to be monitored may cooperate with each other to monitor the microcomputer to be monitored. By monitoring, a highly reliable mutual monitoring device for microcomputers can be obtained.

As explained above, the present invention provides a mutual monitoring device for a plurality of microcomputers to prevent malfunctions of the microcomputers by using the normal output ports, input ports, and reset terminals of the microcomputers. be able to. In particular, when there are three or more microcomputers, the reliability of mutual monitoring for malfunctions and the like increases accordingly.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of a mutual monitoring device for microcomputers according to the present invention. 10,20...microcomputer, 11,
13, 21, 23...output port, 12, 22...
...Input port, 14, 24...Reset terminal, 2
5...Alarm circuit.

Claims (1)

[Scope of utility model registration request] In a device using a plurality of microcomputers, when each microcomputer is processing a program at a predetermined cycle, each microcomputer should monitor a fixed binary repeated diagnostic pulse train that is emitted at a fixed cycle. and each microcomputer to be monitored receives the diagnostic pulse train and determines whether an abnormality has occurred in the computer to be monitored by repeating a certain binary value of the diagnostic pulse train. and a reset signal output means for outputting a reset signal for resetting the computer to be monitored when it is determined that an abnormality has occurred, and an alarm for inputting the reset signal as an alarm signal for issuing an alarm. A mutual monitoring device for microcomputers, characterized by comprising a circuit.