JPH0354923Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a carriage home position detection device that detects the home position of a carriage such as a printer or recorder and executes a predetermined interrupt process. More specifically, it relates to reducing software waste time when detecting the home position.

(Prior Art) For example, in printers and recorders that record while moving a carriage equipped with a recording head in a fixed direction, a home position sensor detects that the carriage has reached the home position, and a detection signal is sent to the printer or recorder. The system is configured to execute predetermined interrupt processing such as stopping the carriage and calculating a reference position.

FIG. 3 is a configuration explanatory diagram showing an example of such a conventional device. In FIG. 3, reference numeral 1 denotes a carriage on which a recording head is mounted, for example, and is moved along a guide shaft 2 in a fixed direction (for example, in a reciprocating direction to the right and left). A home position sensor 3 detects that the carriage 1 has reached the home position (for example, the left end), and sends a detection signal to the interrupt control circuit 4. Note that, as such a home position sensor 3, for example, a mechanical switch or an optical switch is used. A plurality of interrupt signals including a detection signal from the home position sensor 3 are applied to the interrupt control circuit 4 . This interrupt control circuit 4 is connected to a central processing unit (hereinafter referred to as CPU) via an interrupt signal line 5 and a data bus 6.
7 is connected.

In such a configuration, when an interrupt signal is applied via the interrupt signal line 5, the CPU 7 reads the cause of the interrupt from the data applied via the data bus 6, and determines the cause of the interrupt based on the detection signal of the home position sensor 3. In the case of an interrupt, the predetermined interrupt processing as described above is executed.

By the way, in such a configuration, if vibration is applied while the carriage 1 is stopped at the home position, the carriage 1 will vibrate left and right, and the detection signal of the home position sensor 3 will turn on and off in synchronization with the vibration. It may be done. In other words, unnecessary interrupt signals are continuously generated due to vibration.

Conventionally, such devices have been configured such that when unnecessary interrupt signals are added, the CPU 7 disables those interrupt signals during interrupt processing.

(Problem that the invention attempts to solve) However, with this configuration, if interrupt signals occur continuously, it will take a considerable amount of time to process the interrupts to invalidate the interrupt signals. , undesirable.

The present invention focuses on this point, and its purpose is to prevent unnecessary interrupt signals from being applied to the CPU and to disable unnecessary interrupt signals through software interrupt processing. An object of the present invention is to provide a carriage home position detection device that can reduce processing time.

(Means for Solving the Problems) The present invention that achieves the above purpose includes a home position sensor that outputs a detection signal when the carriage reaches the home position, and a home position sensor that outputs a detection signal when the carriage reaches the home position. An AND gate to which a mask signal is added to mask the transmission of the detection signal of the home position sensor for an arbitrary period of time, and an interrupt to execute a predetermined interrupt process according to the detection signal of the home position sensor sent from the AND gate. It is characterized by being configured with a processing circuit.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, and the same parts as in FIG. 3 are given the same reference numerals. In Figure 1, 8 is an AND gate,
The detection signal of the home position sensor 3 is applied to one input terminal, and the CPU
A mask signal is added from 7 to mask the output of the detection signal from the home position sensor 3 for an arbitrary period of time.

FIG. 2 is a configuration explanatory diagram showing a specific example of the configuration shown in FIG. 1. The detection signal of the home position sensor 3 is applied to the data bus 6 via the input port 9, and the mask signal is applied from the data bus 6 to the ant gate 8 via the output port 10.
Here, as the input port 9, for example, a three-state type is used, and as the output port 10, for example, a latch type is used. Note that control signals are applied to these input port 9 and output port 10 from the CPU 7, respectively.

The operation of the device configured in this way will be explained.

When the carriage 1 moves to the left end, the home position sensor 3 outputs a home position detection signal. This detection signal from the home position sensor 3 is applied to the CPU 7 via the AND gate 8 and the interrupt control circuit 4. Then, the CPU 7 uses the data bus 6 to read from the interrupt control circuit 4 that the cause of the interrupt is from the home position sensor 3 through interrupt processing, and executes the predetermined interrupt processing as described above. do. Here, when the mode does not require an interrupt signal from the home position sensor 3, such as when the carriage 1 is stopped for a long time, the output port 10 is connected to the AND gate 8.
``L'' level is added as a mass signal to .

As a result, even if vibrations are applied to the carriage 1 and the detection signals of the home position sensor 3 are turned on and off in synchronization with the vibrations, these detection signals are not sent to the interrupt control circuit 4, and the interrupt control circuit 4
It is possible to prohibit the sending of unnecessary interrupt signals from the CPU 7 to the CPU 7, and it is possible to reduce the conventional interrupt processing time required for invalidating unnecessary interrupt signals by the CPU.

Note that even in this state, the state of the output of the home position sensor 3 can be monitored at any time using the input port 9.

Further, in the above embodiment, an example was described in which the home position of a carriage equipped with a recording head is detected, but it may also be a carriage equipped with, for example, an optical reading head.

(Effects of the invention) As explained above, according to the invention, processing is performed to prevent unnecessary interrupt signals from being applied to the CPU and to disable unnecessary interrupt signals through software interrupt processing. A carriage home position detection device that can save time can be realized, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention;
FIG. 2 is a configuration explanatory diagram showing a specific configuration example of FIG. 1, and FIG. 3 is a configuration explanatory diagram showing an example of a conventional device. 1... Carriage, 2... Guide shaft, 3... Home position sensor, 4... Interrupt control circuit, 5...
Interrupt signal line, 6...Data bus, 7...Central processing unit (CPU), 8...And gate, 9...Input port, 10...Output port.

Claims (1)

[Scope of utility model registration request] A home position sensor that outputs a detection signal when the carriage reaches the home position, and an AND signal that masks the detection signal of the home position sensor and the transmission of the detection signal of the home position sensor for an arbitrary period of time. A carriage home position detection device comprising a gate and an interrupt processing circuit that executes predetermined interrupt processing according to a detection signal from a home position sensor sent from the AND gate.