JPH10281810A - Power circuit for encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate wiring work and maintenance, by connecting a main power source to a backup power source in common, installing a main power source voltage detection circuit and a power source switching circuit, and stopping the power supply to a regular operation circuit and supplying power only to an outage operation circuit when the voltage of the main power source lowers below a fixed value. SOLUTION: A main power source/backup power source 20 in which the main power source 1 and backup power source 7 are connected in common, is connected directly to a regular operation circuit 3 and an outage time operation circuit 4 of an encoder 2 through a first diode 5. A built-in battery 6 comprising the outage operation circuit 4 and a capacitor parallel with the outage time operation circuit 4 is connected to a first diode 5. A power source switching circuit 30 comprising a transistor and a main power source voltage detection circuit 31 are connected to the regular operation circuit 3. When a voltage of the main power source 1 lowers below a fixed level or the power fails, the power source switching circuit is switched by a detection signal 31a, the operation of the regular operation circuit 3 is stopped, and only the outage time operation circuit 4 is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit for an encoder, and more particularly to a main power supply and a backup power supply commonly connected to each other.
It relates to a new improvement for reducing the number of books from two to two.

[0002]

2. Description of the Related Art Conventionally, as a power supply circuit of an encoder of this kind, a configuration shown in FIGS. 3 and 4 has been generally employed. That is, what is indicated by reference numeral 1 in FIG. 3 is a main power supply composed of a power supply of a factory or the like, and the main power supply 1 is directly connected to the normal operation circuit 3 and the power failure operation circuit 4 of the encoder 2 via the first diode 5. Connected. The first diode 5 is connected to the power failure operation circuit 4 and a built-in battery 6 composed of a capacitor arranged in parallel with each other, and to the second diode 8 connected to a backup power supply 7 composed of a battery power supply. . Therefore, when the main power supply 1 failed, only the power failure operation circuit 4 was operated by the backup power supply 7.

[0003]

The power supply circuit of the conventional encoder has the following problems because it is configured as described above. That is, as shown in FIG. 4, the number of power supply lines for the encoder 2 is the sum of the main power supply line 1a for the main power supply 1, the backup power supply line 7a for the backup power supply 7, and the ground line 10 as the ground. Since three wires are required and five or six signal wires are required, a total of about ten wires are required to mount the encoder. Therefore, the number of power lines should be as small as possible. Had become.

[0004]

A power supply circuit of an encoder according to the present invention has a normal operation circuit and a power failure operation circuit provided in the encoder for processing a rotation detection signal.
In an encoder power supply circuit that uses a main power supply and a backup power supply for driving each of the circuits,
A main power supply voltage detection circuit and a power supply switching circuit for detecting the main power supply in the normal operation circuit, while connecting the operation circuits to a main power supply / backup power supply in which the main power supply and the backup power supply are commonly connected; When the voltage of the main power supply falls below a certain level, the power supply switching circuit turns off the power supply to the normal operation circuit and supplies power only to the power failure operation circuit.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a power supply circuit of an encoder according to the present invention will be described below with reference to the drawings. The same or equivalent parts as those in the conventional example will be described with the same reference numerals. In FIG. 1, reference numeral 20 denotes a main power supply / backup power supply to which the main power supply 1 and the backup power supply 7 are connected in common. It is connected directly to the circuit 3 and the power failure operation circuit 4 via the first diode 5. The first diode 5 is connected to a built-in battery 6 composed of a capacitor connected in parallel with the power failure operation circuit 4. The normal operation circuit 3 is connected to a power supply switching circuit 30 including a transistor (or a relay may be used) and a main power supply voltage detection circuit 31. Therefore, using the circuit configuration of FIG.
Is connected to the main power supply / backup power supply 20 composed of the main power supply 1 and the battery power supply 7 as shown in FIG. 2, the number of power supply lines connected to the encoder 2 becomes the main power supply line 1a.
And the ground wire 10, which can be reduced by one compared with the conventional case.

Next, the operation will be described. In FIG. 1, when the voltage of main power supply 1 falls below a predetermined level or a power outage occurs, this voltage level is detected by main power supply voltage detection circuit 31, and power supply switching circuit 30 is switched by this detection signal 31a to perform normal operation. The operation of the circuit 3 is stopped,
Only the power failure operation circuit 4 is operated by the backup power supply 7, and the backup operation of the rotation detection signal of the encoder 2 at the time of the power failure can be performed.

[0007]

The power supply circuit of the encoder according to the present invention
With the above configuration, the following effects can be obtained. That is, since the main power supply and the backup power supply are connected in common and connected to the normal operation circuit and the power failure operation circuit, only two power supply lines are needed, and one power supply line may be required less than the conventional one. When many encoders are used, wiring work and maintenance become much easier.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply circuit of an encoder according to the present invention.

FIG. 2 is a configuration diagram showing a power connection of FIG. 1;

FIG. 3 is a circuit diagram showing a power supply circuit of a conventional encoder.

FIG. 4 is a configuration diagram showing a power connection of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main power supply 2 Encoder 3 Normal operation circuit 4 Power failure operation circuit 7 Backup power supply 20 Main power supply / Backup power supply 30 Power supply switching circuit 31 Main power supply voltage detection circuit

Claims (1)

[Claims] 1. A normal operation circuit (3) provided in an encoder (2) for processing a rotation detection signal, and a power failure operation circuit (4).
And a main power supply (1) for driving each of the circuits (3, 4).
And a main power supply / backup power supply in which the main power supply (1) and the backup power supply (7) are commonly connected in a power supply circuit of an encoder that uses the backup power supply (7).
A main power supply voltage detection circuit (31) and a power supply switching circuit (30) for connecting the respective operation circuits (3, 4) to (20) and for detecting the main power supply (1) to the normal operation circuit (3). ) Is provided, and when the voltage of the main power supply (1) becomes equal to or lower than a certain value, the power supply to the normal operation circuit (3) is turned off by the power supply switching circuit (30), and the power failure operation circuit (4) A power supply circuit for an encoder, wherein the power supply circuit is configured to supply power to only the encoder.