JP2001306115A - Input/output units for programmable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a programmable controller preventing operation errors in input/output unit when power is started. SOLUTION: Programmable controller is composed of output unit 7a-7d outputting electric signals by connecting to outer device, control unit 2 controlling the input/output unit upon commands from CPU unit, insulation circuit unit 8 exchanging signals by insulating control unit 2 and output unit 7a-7d, and power unit 9 generating and supplying driving power Va1, Va2 which drives insulation circuit unit 8 and output unit 7a-7d by outer power Vb. When outer power Vb is started, driving power Va1 is supplied to insulation circuit unit 8. After the insulation unit is started, driving power Va2 is supplied to output unit 7a-7d by power unit 9. By supplying driving power Va2 to output unit 7a-7d before insulation unit 8 is started, operation errors in the output units can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output unit used for a programmable controller including a CPU unit and a power supply unit to input and output electric signals to and from external devices.

[0002]

2. Description of the Related Art FIG. 8 shows an example of the configuration of a conventional input / output unit. The input / output unit is connected to an external device to input or output an electric signal. Therefore, hereinafter referred to as “output unit”) 7a to 7d,
A control unit 2 for controlling the output units 7a to 7d in accordance with a command from a CPU unit (not shown) mounted on a motherboard together with an input / output unit and a power supply unit, and a power supply unit (not shown) via a motherboard Power supply unit 3 for generating an operation power supply Vcc for the control unit 2 by receiving power supply from the control unit 2 and an insulation circuit for insulating the control unit 2 and the output units 7a to 7d and exchanging signals between them. (Photocoupler) 5. In the output units 7a to 7d,
The collector of the phototransistor PT of the photocoupler 5 is connected to an external power supply V1.
It functions as a drive power source for a to 7b. The emitter of the phototransistor PT is directly connected to the base of the output transistor Tr, and the bias resistor R
10 is connected to the emitter of the transistor Tr. The emitters of the output transistors Tr of the output units 7a to 7d are commonly connected, and the common terminal and the output terminals 6a to 6d provided at the collectors of the output transistors Tr are connected to an external device.

Here, as a photocoupler used for the insulating circuit section 5, a non-power-supply type photocoupler that does not require a power supply is usually used in the case of a normal output (or input / output) of about several tens of kHz. For high-speed output (or input / output) of several hundred kHz or more, a so-called high-speed photo IC coupler (hereinafter, referred to as “high-speed photo coupler”) is used.

FIG. 9 shows an example of the configuration of an input / output unit using a high-speed photocoupler in the insulating circuit section 8.

When a high-speed photocoupler is used for the insulation circuit section 8, a drive power supply (about 5 V) is required for the high-speed photocoupler, and when the operation power supply Vcc of the control section 2 is supplied to the insulation circuit section 8 as a drive power supply. The control unit 2 side and the output units 7a to
Since the meaning of insulating the 7d side by the insulating circuit section 8 is lost, a power supply section 20 for generating and supplying a driving power supply Va for driving the insulating circuit section 8 from the external power supply Vb is provided on the output sections 7a to 7d side. ing.

In many of the high-speed photocouplers, the emitter of the phototransistor 8a is connected to the ground pole of the power input terminal of the high-speed photocoupler. It is necessary to

Therefore, the output terminal of the power supply unit 20 is connected to the power input terminal of the high-speed photocoupler shown in FIG. 10, and a pull-up resistor Rp is connected to the base of the output transistor Tr connected to the collector of the phototransistor 8a. Connected via As a result, the driving power Va from the power supply unit 20 is applied to the driving voltage of the insulating circuit unit 8 and the output unit 7a.
To 7d.

[0008]

However, as described above, when the drive power supply for the insulating circuit section 8 and the drive power supply for the output sections 7a to 7d are connected to the same power supply system, the external power supply Vb is turned on. When the drive power Va is supplied from the power supply unit 20 by the power supply unit, the output transistor Tr operates before the insulation circuit unit 8 is activated, and a wrong signal is output from the output units 7a to 7d. .

The high-speed photocoupler is activated when the voltage value of the driving power supply is generally about 4.5 V or more, and the output transistor T
Some of the transistors used for r operate when the voltage value of the driving power supply becomes about 0.6 V or more.

For example, when the external power supply Vb is turned on, the power supply voltage Va of the power supply section 20 starts increasing from time t1, as shown in FIG. 11C, and at time t2, the operating voltage value Vtr of the output transistor Tr. (For example, about 0.6V),
If the starting voltage value Vpc (for example, about 4.5 V) of the high-speed photocoupler is reached at time t3, the distance between the collector and the emitter of the phototransistor 8a of the high-speed photocoupler is
As shown in FIG. 11B, the impedance is high during a time T1 from time t1 to time t3. However, while the high-speed photocoupler has high impedance, the power supply voltage of the drive power supply Va is applied to the base of the output transistor Tr via the pull-up resistor Rp. From time t2 when voltage value Vtr is reached, phototransistor 8a
Until time t3 when the collector-emitter is turned on to activate the high-speed photocoupler, the output transistor Tr is turned on, and an erroneous signal is output from the output units 7a to 7b.

An object of the present invention is to provide an input / output unit of a programmable controller in which a malfunction of an input / output unit during startup is prevented.

[0012]

In order to achieve the above object, the present invention is directed to a programmable controller comprising a CPU unit and a power supply unit for inputting and outputting electric signals to and from external devices. An input / output unit connected to an external device for inputting or outputting an electric signal, a control unit for controlling the input / output unit according to a command from the CPU unit, a control unit, and an input / output unit. A power supply unit, comprising: an insulation circuit unit that insulates the unit from each other and transmits and receives signals between the two units; and a power supply unit that creates and supplies a drive power supply that drives the insulation circuit unit and the input / output unit from an external power supply. Is
When external power is turned on, drive power is supplied to the input / output section after the drive power is supplied to the insulation circuit section and the insulation circuit section is started.After the insulation circuit section is started, input / output from the power supply section is performed. By supplying the drive power to the unit, it is possible to prevent the drive power from being supplied to the input / output unit before the start of the insulation circuit unit, thereby preventing the input / output unit from malfunctioning.

According to a second aspect of the present invention, in the first aspect of the present invention, the power supply section includes a power supply creating section for creating a drive power supply for the insulation circuit section and the input / output section from an external power supply; And a power supply separation unit that supplies the power to the input / output unit separately. The drive power supply separated by the power supply separation unit is supplied to the insulation circuit unit, and after the insulation circuit unit is started, the input / output unit is started. By supplying the drive power to the input / output unit, it is possible to prevent the drive power from being supplied to the input / output unit before the insulation circuit unit is started, thereby preventing the input / output unit from malfunctioning.

According to a third aspect of the present invention, in the second aspect of the present invention, the power supply separating section detects that the voltage value of the drive power supplied to the insulating circuit section has reached the starting voltage value of the insulating circuit section. It is equipped with a voltage detector that outputs a detection signal, and starts supplying drive power to the input / output unit according to the output of the detection signal.After the voltage detector detects the activation of the insulation circuit unit, the power supply is separated. By starting the supply of the drive power from the unit to the input / output unit, it is possible to prevent the drive power from being supplied to the input / output unit before the insulation circuit unit is started, thereby preventing the input / output unit from malfunctioning.

According to a fourth aspect of the present invention, in the third aspect of the invention, the voltage detector determines that the voltage value of the driving power supply supplied to the insulating circuit section has reached the starting voltage value of the insulating circuit section. 4. The method according to claim 3, wherein the detection is performed from the output voltage of
The same effect as that of the invention is achieved.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the power supply separating section includes a voltage dividing circuit for dividing an external power supply voltage supplied to the power generating section, and the voltage detector is provided in the insulating circuit section. It is characterized by detecting from the output voltage of the voltage dividing circuit that the voltage value of the supplied driving power supply has reached the starting voltage value of the insulating circuit section, and the voltage detector detects that the insulating circuit section has started up by the power supply. By detecting the external power supply voltage that is not easily affected by the load connected to the separation unit from the divided voltage, the power supply separation unit can stably supply the drive power while avoiding the effect of the connected load. it can.

According to a sixth aspect of the present invention, in any one of the first to sixth aspects of the present invention, the insulating circuit section includes a photocoupler whose driving power is supplied to a power input terminal of the phototransistor. A transistor to which drive power is supplied to a base connected to the collector of the phototransistor is provided, and the same operation as the invention of any one of claims 1 to 6 is achieved.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects, the voltage detector is a reset IC that changes the output when the input voltage value reaches a predetermined value. When the input voltage value of the reset IC reaches a predetermined value, the insulation circuit section is started up, and the supply of drive power from the power supply separation section to the input / output section in accordance with the output of the reset IC is started. A drive power is supplied to the input / output unit before the start of the unit, so that malfunction of the input / output unit can be prevented.

[0019]

(Embodiment 1) FIG. 1 shows a schematic circuit block diagram of Embodiment 1 of the present invention. Basically Figure 9
And an input / output unit connected to an external device to input or output an electric signal (only the output configuration is illustrated in the illustrated example. ) And output units 7a to 7d having a microcomputer as a main component and responding to an instruction from a CPU unit.
d, an operation power supply unit 3 that receives power supply from a power supply unit (not shown) via a motherboard to create an operation power supply Vcc for the control unit 2, and a high-speed photo IC coupler (hereinafter, referred to as a high-speed photo IC coupler). A high-speed photocoupler), which insulates the control unit 2 from the output units 7a to 7d and transmits and receives signals between them;
b, a power supply unit 9 for generating and supplying drive power supplies Va1 and Va2 for driving the insulating circuit unit 8 and the output units 7a to 7d. Here, in order to simplify the description, the control unit 2
The input side of the operation power supply section 3 and the input side of the insulation circuit section 8 are called a control section block 1, and the output sections 7 a to 7 d, the power supply section 9, and the insulation circuit section 8
Is called an output block 4.

FIG. 2 shows an example of a specific circuit configuration of the power supply section 9 in the present embodiment. Hereinafter, the basic configuration of the power supply section 9 will be described with reference to FIG.

The power supply section 9 is provided with a drive power supply V common to the insulating circuit section 8 and the output sections 7a to 7d from the external power supply Vb.
a, and a drive power supply V
a is the drive power source Va1 of the insulating circuit unit 8 and the output units 7a to 7a.
Power supply separation unit 9 that separately supplies and supplies 7d drive power Va2
b.

The power supply generator 9a is, for example, a DC-DC converter which receives an external power supply Vb having a DC voltage value of about 24V and generates a drive power supply Va having a DC voltage value of about 5V.

The power supply separation unit 9b is connected to the output terminal of the power supply generation unit 9a, and outputs an H level detection signal from the output terminal when the input voltage reaches the detection voltage value V10, for example, a voltage detector such as a reset IC. 10, a PNP transistor Q1 having an emitter connected to the high-potential output terminal of the power generation unit 9a, an emitter connected to the low-potential output terminal of the power generation unit 9a, and a base connected to the output of the voltage detector 10. An NPN-type transistor Q2 connected to the terminal, a resistor R1 connected between the base and the emitter of the transistor Q1, a resistor R2 connected between the base of the transistor Q1 and the collector of the transistor Q2, and a voltage detector 10 And a resistor R3 connected between the output terminal of the power supply generator 9a and the collector of the transistor Q1 and the resistor of the transistor Q2. Capacitor C connected between the jitter
1, and the low-potential-side output terminal of the power generation unit 9a is grounded. The high-potential-side input terminal of the power supply separation unit 9b
The power supply input terminal of the phototransistor 8a shown in FIG. 3 is connected, and the collector of the transistor Q1 of the power supply separation unit 9b is connected to the base of the output transistor Tr shown in FIG. 3 via a pull-up resistor Rp.

When the external power supply Vb is turned on, the power supply section 9 generates a drive power supply Va in the power supply generation section 9a, and connects the insulation circuit section 8 from the high potential side input terminal of the power supply separation section 9b.
Of the driving power supply Va1 is started. Then, the output voltage Va of the power generation unit 9a is input to the voltage detector 10 of the power supply separation unit 9b, and the output voltage Va is detected by the detection voltage value V
When the voltage reaches 10, the voltage detector 10 outputs an H-level detection signal. The power supply separation unit 9b turns on the transistor Q2, which is turned on by the detection signal, and turns on the transistor Q1, whose L level signal is input to the base.
A driving power supply Va2 is supplied from the collector of the transistor Q1 to the output units 7a to 7d.

Here, the detected voltage value V1 of the voltage detector 10
0 is set to be larger than the starting voltage value Vpc of the insulating circuit section 8 (for example, the detection voltage value V10 is about 4.7 V, and the starting voltage value Vpc is about 4.5 V). As a result, the voltage detector 10 determines that the value of the output voltage Va of the power supply creation unit 9a is equal to the voltage value of the drive power supply Va1 supplied to the insulation circuit unit 8, so that the output voltage Va of the power supply creation unit 9a 8 detects that the voltage value of the drive power supply Va1 supplied to the drive circuit 8 has reached the start-up voltage value Vpc of the insulation circuit section 8, and the power supply separation section 9a outputs the output sections 7a to 7a after the start-up circuit section 8 is started up. 7
d to supply drive power Va2.

For example, when the external power supply Vb is turned on and the output voltage Va of the power supply creation unit 9a is changed as shown in FIG.
At time t1, the voltage starts rising, reaches an operating voltage value Vtr (for example, about 0.6 V) of the output transistor Tr at time t2, and at time t3, a starting voltage value Vpc of the high-speed photocoupler.
(For example, about 4.5 V), the drive voltage Va1 of the power supply voltage equal to the output voltage Va
Is supplied, the impedance between the collector and the emitter of the phototransistor of the high-speed photocoupler is high impedance during the time T1 from time t1 to time t3, as shown in FIG. 4B. Here, if the detection voltage value V10 of the voltage detector 10 is set to be higher than the starting voltage value Vpc of the insulating circuit unit 8, the voltage detector 10 changes the output voltage Va of the power generation unit 9a to the detection voltage value V10. Since the detection signal is not output until the output voltage Va reaches the detection voltage value V10, as shown in FIG. 4C, the power supply separation unit 9b supplies the drive power to the output units 7a to 7d from time t1 to time t3 when the output voltage Va reaches the detection voltage value V10. The supply of Va2 is stopped. As a result, FIG.
As shown in (a), the output transistor Tr is turned on at time t.
During the time T2 from 1 to t4, the device is forcibly turned off. After time t4, the forced off state is released, and the phototransistor 8a has already been turned on and the insulating circuit section 8 has been activated.
r does not malfunction and is kept off unless a control signal from the control unit 2 of the control unit block 1 is output.

As described above, the power supply unit 9 of the present embodiment supplies the drive power Va2 to the output units 7a to 7d after the insulation circuit unit 8 is activated, so that the output unit 9 is activated before the insulation circuit unit 8 is activated. It is possible to prevent the output power units 7a to 7d from malfunctioning when the drive power supply Va2 is supplied to the output units 7a to 7d. (Embodiment 2) By the way, in Embodiment 1, the voltage detector 10
Is about 4.7 V, for example, and the rated value of the output voltage of the power generation unit 9 a is about 5 V, for example.
When the difference between the detected voltage value V10 and the rated value of the power supply creation unit 9a is small, if the load to which the drive power supply Va2 is supplied is large, the supply of the drive power supply Va2 from the power supply separation unit 9b becomes unstable. There is.

For example, as shown in FIG.
When the output voltage Va of the power supply creation unit 9a reaches the detection voltage value V10 of the voltage detector 10, the drive power supply Va2 is supplied from the power supply separation unit 9b, and the output units 7a to 7d as shown in FIG. Is supplied with a drive power supply Va2. However, when the load to which the drive power supply Va2 is supplied is large, the value of the output voltage Va of the power supply creation unit 9a decreases and becomes lower than the detection voltage value V10, and the power supply separation unit 9b stops the supply of the drive power supply Va2. As described above, when the load to which the drive power Va2 is supplied is large, the power separation unit 9b causes the power generation unit 9a
Of the driving power supply V
It becomes unstable when a2 is supplied or stopped.

Therefore, in order to stabilize the supply of the driving power Va2 from the power separating unit 9b, the power separating unit 9a according to the present embodiment uses the power of the external power Vb supplied to the power generating unit 9a as shown in FIG. Voltage dividing circuit 11 for dividing voltage Vin
The voltage detector 10 is configured so that the voltage value of the driving power supply Va1 supplied to the insulating circuit unit 8 is equal to the starting voltage value V
It has been detected from the output voltage of the voltage dividing circuit 11 that it has reached pc.

The voltage dividing circuit 11 comprises a series circuit of resistors R4 and R5.
Is connected to the input terminal of

The resistance values of the resistors R4 and R5 are such that the rated value of the output voltage of the voltage dividing circuit 11 becomes sufficiently larger than the detected voltage value V10 of the voltage detector 10 and the external power supply V
b is input and the output voltage of the voltage dividing circuit 11 becomes the detected voltage value V
When the value reaches 10, the voltage value of the drive power supply Va1 of the insulating circuit section 8 is set to be larger than the starting voltage value Vpc of the insulating circuit section 8 and the insulating circuit section 8 is activated.

For example, as shown in FIG.
When the external power supply Vb is turned on to 0, the power supply voltage Vin gradually increases, and the power supply voltage Vin becomes, for example, a voltage value Vi of about 3 V.
At time t1 when the time reaches n2, as shown in FIG. 7D, the output voltage Va of the power generation unit 9a starts to increase. At time t3 when the output voltage Va reaches the starting voltage value Vpc of the insulating circuit section 8, the high-speed photocoupler is turned on as shown in FIG. The power supply voltage Vin is the output voltage from the voltage dividing circuit 11 and the detected voltage value V1 of the voltage detector 10 is
When the voltage value Vin reaches zero, for example, about 12 V (time t4), as shown in FIG.
b starts supply of the drive power supply Va2 to the output units 7a to 7d. Then, when the driving power supply Va2 is supplied to the output units 7a to 7d, the forced off state of the output transistor Tr is released as shown in FIG.

As described above, in the present embodiment, the insulating circuit section 8
Is detected from the output voltage Va of the power generation unit 9a during an unstable period from the voltage value Vpc shown in FIG. 7D to the rated value Vout (for example, about 5 V). By detecting the external power supply voltage Vin that is hardly affected by the load connected to the power supply separation unit 9b from the voltage divided by the voltage division circuit 11, the power supply separation unit 9b
The supply of the drive power Va2 from the power supply can be stabilized while avoiding the influence of the load connected to the power supply separation unit 9b.

Also, since the rated value of the external power supply voltage Vin is sufficiently larger than the detected voltage value V10 of the voltage detector 10,
The output of the voltage dividing circuit 11 obtained by dividing the external power supply voltage Vin can be set higher than the detection voltage value V10. Thus, when the output voltage of the voltage dividing circuit 11 reaches a value close to the rated value, even if the output voltage of the voltage dividing circuit 11 fluctuates, it is possible to make it difficult to become smaller than the detected voltage value V10. The supply of the driving power supply Va2 can be further stabilized.

[0035]

According to the first aspect of the present invention, there is provided an input / output unit used for a programmable controller including a CPU unit and a power supply unit to input and output an electric signal to and from an external device. An input / output unit that is connected to input or output an electric signal, a control unit that controls the input / output unit in accordance with a command from the CPU unit, and insulates the control unit and the input / output unit from each other. It has an insulation circuit section for transmitting and receiving signals, and a power supply section for creating and supplying a drive power supply for driving the insulation circuit section and the input / output section from an external power supply. The power supply section is driven by the insulation circuit section when the external power supply is turned on. The drive power is supplied to the input / output section after the power is supplied and the insulation circuit section is started, so the drive power is supplied from the power supply section to the input / output section after the insulation circuit section is started, so that the insulation circuit section is supplied. Input / output before starting There is an effect that output unit driving power is supplied can be prevented from malfunctioning.

According to a second aspect of the present invention, the power supply section includes a power supply creating section for creating a drive power supply for the insulation circuit section and the input / output section from an external power supply, and separating the created drive power supply into an insulation circuit section and an input / output section. Power supply separation unit that supplies the drive power to the input / output unit after the drive power separated by the power supply separation unit is supplied to the insulation circuit unit and the insulation circuit unit starts. There is an effect that it is possible to prevent the input / output unit from malfunctioning due to the supply of drive power to the input / output unit before the activation of the circuit unit.

According to a third aspect of the present invention, the power supply separating section detects that the voltage value of the driving power supply supplied to the insulating circuit section has reached the starting voltage value of the insulating circuit section and outputs a detection signal. Supply of drive power to the input / output unit in response to the output of the detection signal.After the voltage detector detects the activation of the insulation circuit unit, the supply of drive power to the input / output unit from the power supply separation unit Is started, the drive power is supplied to the input / output unit before the start of the insulation circuit unit, and the input / output unit can be prevented from malfunctioning.

According to a fourth aspect of the present invention, the voltage detector detects that the voltage value of the drive power supply supplied to the insulation circuit section has reached the starting voltage value of the insulation circuit section from the output voltage of the power supply creation section. Thus, the same effect as the third aspect of the invention can be obtained.

According to a fifth aspect of the present invention, the power supply separating section includes a voltage dividing circuit for dividing an external power supply voltage supplied to the power supply creating section, and the voltage detector includes a voltage of the driving power supply supplied to the insulating circuit section. The voltage detector detects from the output voltage of the voltage dividing circuit that the value has reached the starting voltage value of the insulation circuit section.Therefore, the voltage detector determines that the insulation circuit section has started up by the effect of the load connected to the power supply separation section. By detecting the external power supply voltage which is hard to receive from the divided voltage, the power supply separation unit has an effect that the drive power supply can be stably supplied while avoiding the influence of the connected load.

According to a sixth aspect of the present invention, the insulating circuit section comprises a photocoupler in which drive power is supplied to a power input terminal of the phototransistor, and the input / output section has a drive power supply connected to a base connected to the collector of the phototransistor. Is provided, so that the same effect as in any one of the first to sixth aspects of the invention can be obtained.

According to a seventh aspect of the present invention, the voltage detector is a reset IC that changes its output when the input voltage value reaches a predetermined value. The drive of the drive power is supplied to the input / output unit before the start of the insulation circuit unit by starting the insulation circuit unit and starting to supply the drive power from the power supply separation unit to the input / output unit according to the output of the reset IC. There is an effect that a malfunction of the input / output unit can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic circuit block diagram illustrating a first embodiment.

FIG. 2 is a schematic circuit diagram of a power supply unit according to the embodiment.

FIG. 3 is a schematic circuit diagram of an output unit according to the first embodiment;

FIG. 4 is an operation explanatory diagram of the above.

FIG. 5 is an operation explanatory diagram of the first embodiment for showing a comparison with the second embodiment.

FIG. 6 is a schematic circuit diagram illustrating a power supply unit according to a second embodiment.

FIG. 7 is an operation explanatory diagram of the above.

FIG. 8 is a schematic circuit block diagram showing a conventional example.

FIG. 9 is another schematic circuit block diagram of the above.

FIG. 10 is a schematic circuit diagram showing an output unit of the above.

FIG. 11 is an operation explanatory diagram of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control part block 2 Control part 3 Operating power supply part 4 Output part block 7a-7d Output part 8 Insulation circuit part 9 Power supply part Va1, Va2 Drive voltage

Claims (7)

[Claims] An input / output unit used for a programmable controller including a CPU unit and a power supply unit to input / output an electric signal to / from an external device, and is connected to the external device to input the electric signal. Or, an output input / output unit, a control unit that controls the input / output unit according to a command from the CPU unit, and an insulating circuit that insulates the control unit from the input / output unit and transmits and receives signals between the two. And a power supply unit for creating and supplying a drive power supply for driving the insulation circuit unit and the input / output unit from an external power supply. The power supply unit supplies drive power to the insulation circuit unit when the external power supply is turned on. An input / output unit of a programmable controller, which supplies drive power to the input / output unit after the unit is started. 2. A power supply section, comprising: a power supply creating section for creating a drive power supply for an insulation circuit section and an input / output section from an external power supply; and a power supply for supplying the created drive power separately to the insulation circuit section and the input / output section The input / output unit of a programmable controller according to claim 1, further comprising a separation unit. 3. The power supply separation unit includes a voltage detector that detects that a voltage value of a drive power supply supplied to the insulation circuit unit has reached a start-up voltage value of the insulation circuit unit and outputs a detection signal. 3. The input / output unit of a programmable controller according to claim 2, wherein the supply of drive power to the input / output unit is started according to the output of the signal. 4. The voltage detector according to claim 1, wherein a voltage value of a driving power supply supplied to the insulation circuit unit reaches a start voltage value of the insulation circuit unit from an output voltage of the power generation unit. Item 3. An input / output unit of the programmable controller according to Item 3. 5. The power supply separating unit includes a voltage dividing circuit that divides an external power supply voltage supplied to a power supply creating unit, and the voltage detector includes a voltage detector that detects a voltage value of a driving power supply supplied to the insulating circuit unit. 4. The input / output unit of a programmable controller according to claim 3, wherein the detection that the start voltage value has been reached is detected from the output voltage of the voltage dividing circuit. 6. The insulated circuit section includes a photocoupler in which drive power is supplied to a power input terminal of a phototransistor, and the input / output section includes a transistor in which drive power is supplied to a base connected to a collector of the phototransistor. The input / output unit of a programmable controller according to any one of claims 1 to 5, further comprising: 7. The input / output of a programmable controller according to claim 3, wherein the voltage detector is a reset IC that changes its output when an input voltage value reaches a predetermined value. unit.