JPH0216120B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of diagnosing an origin detection circuit of a pulse motor, and more particularly to a method of diagnosing an origin detection range of the circuit.

2. Description of the Related Art Recently, with the spread of various information processing devices, various printers have been developed and put into practical use. Serial printers using a type wheel are used especially when high printing quality is required.

In this serial printer, a pulse motor is used as the drive source for the type wheel. When the type selection is completed, the pulse motor is locked to stop the desired type just before the hammer, and the hammer is driven to print. ing.

When controlling a pulse motor used in such a state in an open loop, it is necessary to determine the origin position of the pulse motor when the power is turned on. This is because the desired type is selected based on the origin of the pulse motor.

There is a method of using a sensor to determine this origin position. For example, when a four-phase pulse motor is alternately excited in two phases, the stopping position of the motor shaft is determined depending on the excitation of each of the AB, BC, CD, and DA phases. Since the state exists periodically on the circumference of one rotation of the motor shaft, a sensor is installed that sends the origin detection signal only in a certain area on the circumference, and the area detected by the sensor is, for example,
This method uses the AB phase as the origin.

In this method, it is necessary that the area on the circumference detected by the sensor is always detected stably.

[Conventional technology]

FIG. 2 shows an example of an origin detection circuit for a pulse motor.

1 is a pulse motor, 2 is a motor shaft, 3 is a disc attached to the motor shaft 2, 4 is a magnet, and 5 is a Hall element. The magnet 4 and the Hall element 5 constitute a sensor.

When the pulse motor 1 is driven and the motor shaft 2 rotates, the disc 3 rotates as shown by the arrow, for example. The Hall element 5 sends a signal to the terminal A when the magnet 4 approaches, and stops sending the signal when the magnet 4 moves away.

Figure 3 is a diagram explaining the quality of the circuit in Figure 2.
AB phase, BC phase, CD phase and
It is a diagram in which the DA phase is developed on a straight line.

The range shown here, that is, the origin in the figure
When the magnet 4 of the disc 3 is in the range from the CD phase to the DA phase, AB phase, BC phase and CD phase, centering on the AB phase, the signal of the Hall element 5 is sent to the terminal A in Fig. 2. The case is good. This is because there is a sufficient margin in the range from the AB phase at the origin to the adjacent AB phase. And other than the range shown here,
All of them are bad from a margin standpoint.

For example, the range indicated by is too wide and the sensor detects the adjacent AB phase as the origin, and the range indicated by is too narrow and the AB phase at the origin cannot be detected due to temperature and changes over time. There is a danger;
The range shown by is biased and has the disadvantage of .

[Problem that the invention seeks to solve]

As shown in Figure 3 above, the detection range of the sensor is:
It is desirable to have sufficient margin against temperature and aging changes. However, in the past, there was no way to detect this margin, and the AB phase at the origin could not be detected.
There is a problem in that the state of the sensor is not known until the origin position is detected incorrectly.

[Means for solving the problem] The above problem is solved by setting a specific point of the motor shaft that stops when a lock current is supplied to a specific excitation phase as the origin, and using this origin as the drive system control reference. In diagnosing an origin detection circuit that detects the rotation angle of the motor shaft in order to determine the specific location of a polyphase pulse motor that means for sequentially switching excitation phases to rotate the motor shaft one step at a time; means for measuring a range up to a stop point at which the detection signal changes on both sides of a stop point due to the specific excitation phase; means for comparing the detected range with a predetermined origin detection range;
The problem is solved by a method for diagnosing a pulse motor origin detection circuit according to the present invention, which is configured to diagnose whether or not the origin detection range is normal.

[Effect]

In other words, the origin detection circuit diagnostic program is activated by a signal instructed by the operator at any time, the pulse motor is stopped at a specific excitation phase within the area detected by the sensor, and excitation current is sequentially supplied from the excitation phase adjacent to the specific excitation phase. By rotating the motor shaft one step at a time, memorizing the range where the sensor's detection signal stops, and comparing it with a predetermined range, changes in the detection range due to changes in the sensor over time, temperature changes, etc. It detects and examines the margin.

〔Example〕

FIG. 1a is a block diagram of a circuit showing one embodiment of the present invention, and FIG. 1b is a diagram illustrating a method of margin testing of a sensor.

The processor 6 reads various programs stored in the ROM 7 and operates.

Print data is sent from the host device via the interface control circuit 9. The processor 6 once writes this print data into the RAM 8, reads it out, extracts a print code from the print data, and sends it to the type selection control circuit 12. The type selection control circuit 12 controls the type selection pulse motor 13 to rotate the type wheel in order to select a desired type based on this print code.

When the selection of type is completed, the processor 6 controls the hammer magnet drive circuit 14 to energize the hammer magnet 15 and drive the hammer to strike the type provided on the type wheel to print. At the same time, the space control circuit 10 is controlled to control the space motor 1.
1 to perform a spacing motion so that the selected type on the type wheel is positioned at the printing position.

When the processor 6 extracts a line feed instruction from the print data read from the RAM 8, it controls the line feed control circuit 16 to drive the line feed motor 17 to perform a paper feed operation.

Processor 6 is an operator panel (not shown)
When a sensor margin test command is received from the upper switch SW via input port 18, the ROM
The origin detection circuit diagnostic program is read from 7 and a sensor margin test is performed as shown in FIG. 1b.

The processor 6 controls the type selection control circuit 12 to drive a type selection pulse motor (hereinafter abbreviated as motor).
13 is rotated, and the origin detection area is detected by a signal input from the Hall element 5 of the sensor shown in FIG. 2 via the terminal A and the input port 18. When this region is detected, the processor 6 supplies a lock current to the AB phase to stop the motor 13 at the origin position shown in FIG.

Next, the processor 6 monitors the signal from the Hall element 5 and rotates the motor 13 one step at a time by sequentially switching the excitation phase until the output from the Hall element 5 changes from BC phase to CD phase to DA phase. let For example, if the output of the Hall element 5 changes from "H" to "L" in the DA phase shown in the figure, this position, that is, the DA phase, is stored in the RAM 8, and the excitation phase is switched in the opposite direction to the above, and the output is changed from "H" to "L". When the output of the Hall element 5 changes from "H" to "L" in the BC phase shown in FIG. to stop at the origin AB phase.

Therefore, the number of steps from the AB phase to the DA phase and the number of steps from the AB phase to the BC phase are stored in the RAM 8.

By the above operation, it is possible to know how many steps the sensor's detection range is secured on both sides of the origin. After that, processor 6 uses ROM7
By comparing the setting range stored in the RAM 8 with the actual measurement range stored in the RAM 8, the margin of the origin positioning operation can be self-diagnosed.

〔Effect of the invention〕

As explained above, in the present invention, the margin can be confirmed during the origin positioning operation, so it is possible to prevent malfunctions.
The reliability of the device can be improved.

[Brief explanation of drawings]

Fig. 1a is a block diagram of a circuit showing an embodiment of the present invention, b is a diagram explaining a sensor margin test method, Fig. 2 is a diagram showing an example of a pulse motor origin detection circuit, Fig. 3 2 is a diagram illustrating the quality of the circuit shown in FIG. 2. FIG. In the figure, 1 is a pulse motor, 2 is a motor shaft, 3 is a disk, 4 is a magnet, 5 is a Hall element, 6 is a processor, 7 is a ROM, 8 is a RAM, 9 is an interface control circuit, and 10 is a space control circuit,
11 is a space motor, 12 is a type selection control circuit, 13 is a type selection pulse motor, 14 is a hammer magnet drive circuit, 15 is a hammer magnet,
16 is a line feed control circuit, 17 is a line feed motor, and 18 is an input port.

Claims (1)

[Scope of Claims] 1. The above-mentioned polyphase pulse motor which uses a specific position of the motor shaft that stops when a lock current is supplied to a specific excitation phase as the origin, and uses this origin as a control reference for the drive system. In diagnosing the origin detection circuit that detects the rotation angle of the motor shaft in order to determine a specific location, each adjacent excitation phase is sequentially switched and excited from the specific excitation phase until the detection signal of the origin detection circuit changes. means for rotating the motor shaft one step at a time; means for measuring the range up to the stop point where the detection signal changes on both sides of the stop point due to the specific excitation phase; and a predetermined origin for the measured range. A method for diagnosing an origin detection circuit for a pulse motor, comprising: means for comparing with a detection range, and configured to diagnose whether or not the origin detection range of the origin detection circuit is normal.