JP2002163009A - Controller for input and output of contact point - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome problems that overload protection for a wire and the like outside a controller is not taken into account in a contact controller such as a sequencer, that a current is not detected in a controller side although the current of an allowance limit value or more flows sometimes in an external common line when all the output contact points are turned on, and that overload protection is not provided for the outside of the controller though a fuse is provided in the common line inside the controller. SOLUTION: A means is provided in the controller to input and store an actual load value in the every contact point, and conditions where the common line is brought into overloaded. When the contact points are on/off-controlled by the controller, the presence of the overload is judged in parallel based on the conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact input / output control device for controlling the input / output of a contact, such as a sequencer, which can protect an internal circuit and its peripheral circuits from overload.

[0002]

2. Description of the Related Art A conventional device for controlling the input / output of contacts, such as a sequencer, has a CPU 2 inside a sequencer main body 1 as shown in FIG. Data for sequence control is taken in, an external input is taken in via the input / output circuit 4 in accordance with the data, and an external actuator is driven by operating an output contact.
Here, the ladder data in the ladder data setting unit 3 is generally a rewritable memory element, and data for sequence control is written by a programming tool such as a personal computer and is mounted in the sequencer main body 1.

[0003] Sequencer body 1 and external solenoid 8a
As shown in the circuit diagram of FIG. 5, when the transistor output contact 6a of the output circuit 5 of the sequencer body 1 is turned on, a current flows through the signal line 7a, and the solenoid 8a is turned on. The current passing through the solenoid 8a returns to the power supply 10 through the common line 9.

[0004]

SUMMARY OF THE INVENTION Solenoids 8a to 8d
5 is controlled by the sequencer main body 1. In the circuit as shown in FIG. 5, signal lines 7a to 7d connecting the sequencer main body 1 and the solenoids 8a to 8d have the same size including the common line for convenience in wiring. Often done. In this case, even if the allowable current value of the electric wire has a margin with respect to the load current of each solenoid, a current exceeding the allowable value may flow through the common wire 9 when a plurality of solenoids are turned on at the same time.

However, only data for sequence control is programmed in the ladder data.
U2 cannot stop the sequence control at the time of overload and cannot protect the external circuit of the sequencer body 1 or the internal circuit of the sequencer body 1 from overload. Some sequencer bodies 1 have a fuse in the common line. However, in general, this fuse is intended to protect the internal circuit of the sequencer body 1 and has a common line 9 and a connector outside the sequencer body 1. In the case where the current capacity is small, the protection function against the outside is not performed at all. Further, the fuse has a fixed capacity, and is not suitable for flexibly performing optimal overload protection for the intended use, such as when the overload condition differs between the electric wire and the connector. Furthermore, replacement work when the fuse is blown is troublesome.

SUMMARY OF THE INVENTION The present invention has been made under the circumstances described above, and an object of the present invention is to provide a contact input / output capable of overload protection that is optimal for use, including an internal circuit and an external circuit of a control device. It is to provide a control device.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a contact input / output device having a common line load monitoring means, and in particular, it is possible to set an actual load value for each contact connected to a common line. The present invention is achieved by a contact input / output control device characterized by comprising means and means for setting an overload condition using the set value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The connection circuit between the sequencer body and the solenoid external to the sequencer is the same as in the conventional example, and will be described with reference to FIG.

FIG. 1 shows a configuration of a contact input / output control device according to an embodiment of the present invention. As shown, the control device includes a CPU 2A, a ladder data setting section 3A, an input / output It has a circuit 4A, an overload protection setting unit 11, an output storage unit 12, and an alarm output circuit 13. Here, the overload protection data in the overload protection data installation unit 11 is data of conditions for overload protection and is accessible from the CPU 2A. However, like the ladder data, it is programmed by a programming tool such as a personal computer. It is mounted in the sequencer body 1A. Although the ladder data setting unit 3A and the overload protection data setting unit 11 are shown as separate blocks in FIG. 1, it is of course possible to write data in the same element.

Next, a method of setting overload protection data will be described. FIG. 2 shows an example of a setting screen when programming overload protection data. FIG. 2 (a) is an explanatory diagram of an actual load setting, and FIG. 2 (b) is an explanatory diagram of an overload condition setting table. ing.

In FIG. 2A, the actual load is set for each contact connected to the common line, and in FIG. 2B, the condition for overloading the common line 9 is set. Figure 2 here
The output 1 in (a) corresponds to the solenoid 8a in FIG. 5, and its actual load current value Ia is set. FIG. 2
Output 2, output 3, and output 4 of (a) are solenoids 8b, 8
c and 8d corresponding to actual load currents, respectively.
Ic and Id are set. In general, the overload condition is defined by the sum of current values flowing per unit time.
In (b), a unit time and a load current value are set. In the example of FIG. 2, when the overload condition is set, the load current value is set to I1 under condition 1.
And the unit time is set to T1. This corresponds to the time T1 and the load current value I1 between the present and the time T1 before.
The setting is such that if a load current equal to or more than the product flows, it is regarded as an overload.

FIG. 3 shows an example of an operation time chart of the sequencer main body 1A. In the figure, the upper part of the waveform shows the solenoids 8a to 8d turned on, and the lower part shows the solenoids 8a to 8d.
8d is off. Here, the output 1 from the time T1 before to the present, that is, the total sum of the load current of the solenoid 8a is the product of ta and Ia. Similarly, the load of the solenoid 8b of the output 2 is the product of tb and Ib, the load of the solenoid 8c of the output 3 is the product of (tc1 + tc2) and Ic, and the output 4
Is the product of td and Id. Accordingly, the sum of the load currents flowing through the common line from the time before the time T1 until the present time is ta · Ia + tb · Ib + (tc1 + t
c2) · Ic + td · Id. If T1 · I1 <t
a · Ia + tb · Ib + (tc1 + tc2) · Ic + t
If d · Id, the common line will be overloaded.

In FIG. 1, a CPU 2A fetches data for sequence control from ladder data 3A, controls external input / output according to the data, and at the same time outputs 1, output 2, output 3, output 4, The on / off time of is stored. While controlling the contact, the CPU 2A constantly sums the total load current flowing through the common line from T1 hours before to the present based on the overload protection data of the overload protection data setting unit 11 and the data of the output storage unit 12. It is calculated and compared with the allowable value T1 · I1. If the sum of the load currents exceeds the allowable value, the CPU 2A sets the alarm output circuit 13
To generate an alarm to the outside, or stop the control after the alarm is generated to perform overload protection.

The condition set in the overload condition setting explanatory diagram shown in FIG. 2B need not be limited to one.
Multiple condition settings are possible. For example, it is also possible to set two conditions, that is, a condition for protecting the wire from overloading and a condition for protecting the connector, and stop the control when one of them is overloaded.

Further, it is naturally possible to set such that it stops within one minute under a load twice the rated capacity like a general fuse.

The condition for overload is not limited to the sum of products, but the condition of overload can be set using a general function or the like. It is also possible to reflect on the condition of overload.

[0017]

As described above, according to the present invention, it is possible to set the actual load value of each contact connected to the common line by incorporating the load monitoring of the common line, and to use the set value to set the actual load value. It is possible to set conditions for overload,
The overload protection optimal for the intended use, including the internal circuit and the external circuit of the contact input / output control device, can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a contact input / output device according to an embodiment of the present invention.

FIG. 2A shows a setting screen at the time of overload protection data programming. FIG. 2A is an explanatory diagram of actual load setting, and FIG.
(B) is an explanatory diagram of overload protection condition setting.

FIG. 3 is an operation time chart of the sequencer body according to the present invention.

FIG. 4 is a diagram showing a configuration of a conventional contact input / output device.

FIG. 5 is a connection circuit diagram of a sequencer main body and an external solenoid in the contact input / output device.

[Explanation of symbols]

 1, 1A Sequencer main body 2, 2A CPU 3, 3A Ladder data setting section 4, 4A I / O circuit 5 Output circuit 6a, 6b, 6c, 6d Transistor output contact 7a, 7b, 7c, 7d Signal line 8a, 8b, 8c, 8d solenoid 9 common wire 10 power supply

Claims (2)

[Claims] 1. A contact input / output control device for controlling the input / output of a contact, comprising a load monitoring means for a common line. 2. The load monitoring means for the common line includes means for setting an actual load value for each contact connected to the common line, and means for setting an overload condition using the set value. The contact input / output control device according to claim 1, comprising: