JP3062989B2 - Coil drive control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil drive control device and, more particularly, to a device for controlling the drive of an actuator drive coil incorporated in an actuator detachable from a device body.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional coil drive control device. In FIG. 3, one end of a coil 32 built in an actuator 31 is connected to a PNP through a connector 33.
Connected to the collector of transistor 34. PNP
The emitter of the transistor 34 is connected to the plus terminal of the power supply 35, and the minus terminal of the power supply 35 is connected to the other end of the coil 32 via the connector 33. In addition, power supply 3
5 is connected to the ground line 36
Called. The base of the PNP transistor 34 is connected to the output terminal of the drive circuit 37, and the drive circuit 3
The input terminal 7 is connected to the output terminal of the control unit 38.

[0003] In the coil drive control device having the above-described configuration, the actuator 31 to be driven is, in many cases, arranged away from the device main body 39 surrounded by a broken line in the figure.
A connector 33 for relay is provided on the wiring leading to the wiring, and division is performed for each functional block. The actuator 31 may or may not be required depending on the specifications of each device. Whether or not the actuator 31 is mounted is determined according to the necessity of the user and the selling price of the device.
At the time of mounting, the coil 32 is mounted on the device body 39 on the circuit.
Connected to. Furthermore, in that case, the mechanism including the actuator 31 may be a so-called optional device that can be easily attached and detached later.

Next, the operation of the circuit shown in FIG. 3 will be described.
First, when it becomes necessary to operate the actuator 31, the control unit 38 gives an operation command to the drive circuit 37. The drive circuit 37 receiving this operation command sets the P
By passing a base current through the NP transistor 34, the transistor 34 is turned on. When the PNP transistor 34 is turned on, a driving current flows from the power supply 35 to the coil 32 through the transistor 34, whereby the actuator 31 performs a desired operation.

[0005]

However, in the conventional coil drive control device having the above-described configuration, when the coil 32 is on the side where the coil 32 is added as an option, the control unit 38 connects the coil 32 to the device main body 39. There is a problem in that it is not possible to determine whether the operation is performed when the actuator 31 is added or the operation when the actuator 31 is not added. Therefore, in order to be able to recognize that the coil 32 is connected, as shown in FIG. 4, one terminal is added to the connector 33, and the optional device side of the additional terminal 41 is connected to the ground line 36. On the other hand, a configuration may be adopted in which the device body side is connected to the control unit 38 via the signal line 42 and the signal line 42 is connected to the logic power supply via the pull-up resistor 43.

According to this, when the actuator 31 which is an optional device is connected, the additional terminal 4 is connected.
1 is connected to the ground line 36, the signal line 42 is at the Lo level, and when the actuator 31 is not connected, the terminal of the connector 33 is open and the signal line 42 is pulled. Since the signal line 42 is connected to the logic power supply via the up resistor 43, the signal line 42 becomes Hi level. Therefore, the control unit 38 can recognize whether or not the actuator 31 is connected to the apparatus main body 39 by reading the level change of the signal line 42. However,
When this configuration is employed, the number of poles of the connector 33 increases, and wiring is added. Therefore, there is a new problem that the cost increases due to an increase in parts cost and man-hour.

As another method, the presence or absence of connection of the actuator 31 is manually set using a dip switch, or the operation of the actuator 31 specified by an operation from an operation panel of the apparatus or a command from a higher-level apparatus or the like. The information on the presence or absence of connection of the actuator 31 is stored in a nonvolatile memory provided inside the apparatus, and the control unit 38 refers to the setting of a dip switch or the contents of the nonvolatile memory as necessary. Is also conceivable. However, in the case of these methods, the addition of a new dip switch or a non-volatile memory leads to an increase in cost, and the operator determines whether or not the actuator 31 is connected and the set information. Because of the operation,
There is a problem that it is not possible to prove later whether the obtained information is true or not, and if set incorrectly, a malfunction will occur, possibly leading to destruction.

The present invention has been made in view of the above problems, and has as its object to provide a coil drive control device capable of reliably recognizing the presence or absence of an actuator connection with a minimum increase in cost. Is to provide.

[0009]

SUMMARY OF THE INVENTION A coil drive control device according to the present invention is a drive control device for an actuator drive coil built in an actuator detachable from a device main body. A closed loop including an actuator driving coil is formed, and a detection circuit for detecting that the coil is connected based on a current flowing through the closed loop is provided.

[0010]

In the above-described coil drive control device, when the actuator is mounted, the detection circuit forms a closed loop including the actuator drive coil. Here, when the actuator driving coil is not driven, a drive signal is not supplied to the coil, and a current flows in a closed loop. Therefore, the detection circuit detects that the actuator driving coil is connected based on the current. I do. When the actuator is not mounted, a closed loop including the actuator driving coil is not formed.
The detection circuit can detect that the actuator driving coil is not connected.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment of the present invention. In FIG. 1, one end of a coil 12 built in an actuator 11 is connected to a P
It is connected to the collector of the NP transistor 14. P
The emitter of the NP transistor 14 is connected to the positive terminal of the power supply 15, and the negative terminal of the power supply 15 is connected to the connector 13.
To the other end of the coil 12. Note that a connection line to the negative terminal of the power supply 15 is hereinafter referred to as a ground line 16. The base of the PNP transistor 14 is connected to the output terminal of the drive circuit 17, and the input terminal of the drive circuit 17 is connected to the output terminal of the control unit 18. The control unit 18 includes a CPU, a microprocessor, and the like.

On the other hand, the collector of the PNP transistor 14 is connected to the cathode of a diode 19, and the anode of the diode 19 is connected to one end of a resistor 20. The other end of the resistor 20 is connected to the base of the PNP transistor 21, and the emitter of the transistor 21 is connected to the positive terminal of the logic power supply 22. Although the wiring of the logic power supply 22 is not shown, the logic power supply 22 also serves as a power supply for logic circuits such as the drive circuit 17 and the control unit 18. The collector of the PNP transistor 21 is connected to one end of the resistor 23 and to the control unit 18 via the signal line 24. The other end of the resistor 23 is connected to the ground line 16. This diode 1
9, a resistor 20, a PNP transistor 21 and a resistor 23 constitute a coil detection circuit 25 for detecting whether or not the coil 12 is connected.

Next, the circuit operation of the above configuration will be described. First, when it becomes necessary to operate the actuator 11, the control unit 18 issues an operation command to the drive circuit 17. Upon receiving this operation command, the drive circuit 17
The transistor 14 is turned on by supplying a base current to the transistor 14. PNP transistor 1
4 is turned on, the power supply 1
A drive current flows from 5 to the coil 12, whereby the actuator 11 performs a desired operation.

Next, the operation of the coil detection circuit 25 will be described. When the actuator 11 is not operated, that is, when the PNP transistor 14 is off, the operation differs depending on whether or not the coil 12 is connected. First, when the coil 12 is connected, the logic power supply 22
From the emitter-base of the PNP transistor 21, the resistor 20, the diode 19, the coil 12, and the ground line 16.
A closed loop is formed which returns to the logic power supply 22 through
The base current of the PNP transistor 21 flows through this closed loop, and as a result, the transistor 21 turns on. Then, a current flows through the resistor 23, and the point A becomes Hi level.
On the other hand, when the coil 12 is not connected, the closed loop is not formed, and the base current does not flow through the PNP transistor 21, so that the PNP transistor 21 is turned off. Then, the point A is pulled down to the ground level by the resistor 23 and becomes the Lo level.

In the coil detection circuit 25 having the above-described configuration, the base current of the PNP transistor 21 always flows through the coil 12 when the coil 12 is connected. Therefore, if the base current is large, the coil 12 may malfunction. However, considering the case where the control unit 18 is configured by a CPU, a microprocessor, and the like, most of the IC manufacturing process is a CM process.
Since it is the OS, the current I _IL flowing out of the input terminal of the control unit 18 when the Lo level is input from the coil detection circuit 25 is very small. As a result, the resistance value of the resistor 23 can be set large, so that the collector current of the PNP transistor 21 can be extremely small. Therefore, the collector current is increased by the DC current amplification factor h of the PNP transistor 21.
_The base current obtained by dividing by _fe is even smaller,
Since it can be set to a level that can be ignored compared to the current that needs to flow through the coil 12 to operate the actuator 11, the base current
Does not malfunction and there is no practical problem.

Next, the circuit operation of the coil detection circuit 25 when the actuator 11 is operated will be described. In this case, since the PNP transistor 14 is on, the PNP voltage is supplied from the power supply voltage V15 of the power supply 15 to the point B.
A voltage _obtained by subtracting the on-state voltage V _CESAT at the time of saturation of the transistor 14 appears. Generally, the power supply voltage V15 for the actuator
Is the power supply voltage V of the logic power supply 22 represented by + 5V
At this time, the base current of the PNP transistor 21 does not flow, so that the PNP transistor 21 is turned off. As a result, the point A becomes Lo level regardless of the presence or absence of the coil 12. Note that the diode 19 in FIG.
Is provided to prevent the PNP transistor 21 from being destroyed when the power supply voltage V15 of the power supply 15 is higher than the voltage of the logic power supply 22, and is deleted when there is no possibility of destruction, It is possible to short circuit.

The control unit 18 monitors the level of the signal line 24 to thereby control the actuator 11 having the coil 12 built therein.
The presence or absence of the connection is determined. The processing procedure of the control unit 18 at that time will be described with reference to the flowchart of FIG. In the following description, the operation of the device that is not directly related to the present invention is a normal process, and the description is omitted.

First, the controller 18 controls the actuator 11
It is determined whether or not is being driven (step S1).
1). If not, the level at point A is read (step S12), and it is checked whether the read level is at the Hi level (step S13). At this time, if it is at the Hi level, the actuator presence flag is set (step S14), and then the process proceeds to a normal process (step S15). If it is determined in step S11 that the actuator 11 is being driven, or if the read level is low in step S13.
If it is determined that the level is the o level, the process directly proceeds to the normal processing (step S15). In this normal process, the control unit 18 recognizes the presence or absence of the connection of the actuator 11 based on whether or not the actuator presence flag is set, and executes a process according to the presence or absence of the connection.

[0019]

As described above, according to the present invention,
In a drive control device for an actuator driving coil built in an actuator that is detachable with respect to the device main body, a detection circuit that forms a closed loop including the actuator driving coil when the actuator is mounted is provided,
With the configuration that detects the connection of the coil based on the current flowing through the closed loop, the presence or absence of the connection of the coil can be reliably detected with a simple circuit configuration, thereby minimizing costs. As a result, the intended purpose can be achieved, and reliable control according to the required specifications for the device can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing procedure of a control unit.

FIG. 3 is a circuit diagram showing a conventional example.

FIG. 4 is a circuit diagram showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Actuator 12 Actuator drive coil 13 Connector 14, 21 PNP transistor 17 Drive circuit 18 Control part 22 Logic power supply 25 Coil detection circuit

Claims (1)

(57) [Claims] 1. A drive control device for an actuator drive coil built in an actuator that is detachable from an apparatus main body, wherein the drive control device forms a closed loop including the actuator drive coil when the actuator is mounted. A coil drive control device comprising a detection circuit for detecting that a coil is connected based on a current flowing through a closed loop.