JPH08221108A - Remote i/o system of plc - Google Patents

Abstract

PURPOSE: To easily set the filter constant of an input filter without the replacement of a unit or direct setting at a remote slave station unit. CONSTITUTION: The filter constant transmission part 15a of a remote master station unit(RM) 15 generates a filter constant setting frame and outputs it to the remote slave station unit(RT) 24 through a communication control part 15b. The remote slave station unit 24 receives the frame by a communication control part 24c and passes it to a filter constant data latch part 24a3. The filter constant data latch part 24a3 sends a select signal SEL out to a clock selector 24a2 on the basis of the frame. The clock selector 24a2 selects one clock signal CLK out of clock signals CLK1-CLK4 of different frequency on the basis of the select signal SEL and sends it out to a digital filter 24a1 to set the filter constant of the digital filter 24a1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PLC remote I / O system comprising a remote master station unit equipped with a CPU unit and a remote slave station unit connected to the remote master station unit via a communication cable. .

[0002]

2. Description of the Related Art In a factory or the like, a plurality of distributed devices are combined into one PLC (programmable controller).
In order to control by PL, a PL consisting of a remote master station unit equipped with a CPU unit and a remote slave station unit connected to the remote master station unit via a communication cable.
C remote I / O system is adopted.

In such a PLC remote I / O system, in order to prevent erroneous input due to chattering of a device connected to the input end of the input unit and ambient noise, an input filter is provided to the remote slave station unit and the input unit. It is provided.

For example, the following two methods are known as methods for providing an input filter.

.. A method to cut unnecessary pulses by configuring a CR filter using resistors and capacitors in the input unit.

[0006] A method to cut unnecessary pulses by installing a digital filter in the remote slave station unit. The sampling clock used for the digital filter is changed by a switch or the like to change the filter constant.

[0007]

In such a PLC remote I / O system, the effective input pulse width differs depending on the input device connected to the parallel input terminal of the input unit, and the system application is different. Since the required input pulse width varies depending on the program and the surrounding noise environment, it was necessary to adjust and set the filter constants of the input filters provided in the remote slave station unit and input unit on site after the system was constructed. .

However, in the above conventional method, since the CR filter is used as the input filter, the setting of the input pulse width is fixed, and the unit provided with the input filter is replaced to adjust the filter constant. Or,
Alternatively, when increasing the effective input pulse width, it is very troublesome to add a filter to the outside.

Further, in the above conventional method, it is necessary to directly set the switch of the digital filter provided in the remote slave station unit or the input unit in order to adjust the filter constant. Since it is generally installed at a position several hundred meters away from the CPU unit and the remote master station unit, there is a problem that setting it for each remote slave station unit takes a lot of time.

Therefore, the present invention has been made by paying attention to such a problem, and it is possible to easily set the filter constant of the input filter without exchanging the unit or directly setting it in the remote slave station unit, and to set it arbitrarily. It is an object of the present invention to provide a PLC remote I / O system capable of selecting the input pulse width of the PLC.

[0011]

In order to achieve the above object, in the invention according to claim 1, a remote master station unit connected to a CPU unit via a bus, and a remote master station unit connected to a remote master station unit via a communication cable. In the PLC remote I / O system including the remote slave station unit, the CPU unit or the remote master station unit has filter constant transmitting means for transmitting the filter constant of the input filter of the remote slave station unit. It is characterized in that the remote slave station unit has a filter means for performing a filtering operation based on the filter constant transmitted by the filter constant transmitting means.

According to the second aspect of the invention, the remote master station unit connected to the CPU unit via the bus, and the remote master station unit connected to the remote master station unit via a communication cable and data communication with the remote master station unit by polling communication. PL consisting of remote slave station unit
In the remote I / O system of C, the CPU unit or the remote master station unit has a polling interval setting means for setting a polling interval from the remote master station unit to the remote slave station unit.

According to the third aspect of the present invention, a remote PLC unit including a remote master station unit connected to the CPU unit via a bus and a remote slave station unit connected to the remote master station unit via a communication cable. In the I / O system, the CPU unit or remote master station unit counts the number of consecutive matches of the data input from the remote slave station unit, and ignores the input data if the count value is less than the reference count. On the other hand, it is characterized by having a communication control means for taking in the input data when the number of times is equal to or more than the reference number and a reference number setting means for setting the reference number of the communication control means.

[0014]

According to the present invention, the CPU unit or the remote master station unit transmits the filter constant of the input filter of the remote slave station unit, and the remote slave station unit filters the filter constant based on the transmitted filter constant. Perform an operation to select any input pulse width.

According to the second aspect of the invention, the CPU unit or the remote master station unit selects an arbitrary input pulse width by setting the polling interval from the remote master station unit to the remote slave station unit, and the polling interval is selected. Set the filter constant for the filter operation by.

According to the third aspect of the invention, the CPU unit or the remote master station unit side counts the number of consecutive matches of the data input from the remote slave station unit, and if the count value is less than the reference number, the count value is input. The input data is fetched when the number of times exceeds the reference number, but the input number is selected by setting the reference number at that time, and the filter constant for the filter operation based on the reference number is set. To do.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A PLC remote I / O according to the present invention will be described below.
An embodiment of the system will be described with reference to the drawings.

FIG. 1 shows a PLC remote I according to the present invention.
2 shows the configuration of the / O system. This PLC remote I / O system is configured by connecting a remote master station device 1 and remote slave station devices 2 and 3 via a connection cable 4.

The remote master station device 1 includes a CPU unit 11 for executing a user program and a power supply unit (P
S) 12, an input unit (IN) 13 and an output unit (OU) that are connected to a relay or the like to input and output data.
T) 14 and a remote master station unit (R) which performs data communication processing between the slave stations 2 and 3 to which the connection cable 4 is connected.
M) 15 etc. are installed.

The remote slave station device 2 includes a power supply unit 2
1, an input unit 22 and an output unit 23 that are connected to the relay 25, the sensor 26, etc. to input / output data.
And a remote slave station unit (RT) 24, etc., which is connected to the connection cable 4 and performs data communication processing with the master station 1.

Further, the remote slave station device 3 includes a sensor 3
3, the input unit 31 connected to the switch 34 and the like for inputting data, and the master station 1 connected to the connection cable 4.
Remote slave station unit 3 that performs data communication processing with
2 etc. are installed.

FIG. 2 shows a PLC remote I according to the present invention.
2 shows a configuration example of a main part of the first embodiment of the I / O system, and includes a remote master station unit (RM) 15 shown in FIG.
The remote slave station unit (RT) 24 shows the configuration of the main part of the first embodiment.

The remote master station unit 15 has a filter constant transmitting section 15a for creating and transmitting a filter constant setting frame, which will be described later, based on the setting of switches and the like, and a communication control section 15b.

The remote slave station unit 24 has an input filter 24a for filtering the parallel input data from the input unit 22, a buffer 24b for receiving the input data via the input filter 24a, and a communication controller 24.
c and.

The input filter 24a selects one of the digital filters 24a1 configured as shown in FIG. 4 and the clock signals CLK1 to m (m = 4 in this embodiment) having different frequencies. Digital filter 24
A clock selector 24a2 to be sent to a and a filter constant data latch section 24a3 which receives a filter constant setting frame from the remote master station unit 15 and outputs select signals SEL1 to SEL1 (n = 2 in this embodiment). Has been done.

FIG. 3 shows a filter constant setting frame created and transmitted by the filter constant transmitter 15a.

The filter constant setting frame F is composed of an address of the remote slave station unit 24 which is a transmission destination, a filter constant setting command for instructing the setting of the filter constant, and setting data indicating the filter constant. . By transmitting this filter constant setting frame F, it is possible to perform initial setting and adjustment of the filter constant, change of the filter constant, and the like.

FIG. 4 shows the configuration of the digital filter 24a1.

The digital filter 24a1 is a 3-bit digital filter, and is a clock signal CLK.
Data from IN unit 22 based on
Shift register (SR) 24a for parallel output from 0 to Q2
11 and an AN for inputting its 3-bit parallel outputs Q0 to Q2
D circuit 24a12 and AND circuit 24a13 of negative input / negative output, AND circuit 24a12 and D-FF 24a
OR circuit 24a14 for inputting the output of 16 and OR circuit 24a
It is composed of an AND circuit 24a15 which inputs the output of a14 and the negative output of the AND circuit 24a13, and a D-FF 24a16 which inputs the AND circuit 24a15.

FIG. 5 shows the digital filter 24a1.
Shows the operation of.

First, as shown in FIG. 5 (a), the pulse signals A and B are input from the IN unit 22 to the D terminal of the shift register (SR) 24a11, and as shown in FIG. 5 (b), the shift register 24a11. And D-FF24a16
It is assumed that the clock signal CLK having the cycle t is input to the CLK terminal of the.

Then, as shown in FIGS. 5 (a) and 5 (b), the pulse signal A is turned on for only two cycles of the clock signal CLK, and therefore, as shown in FIG. 5 (c), the AND circuit 24.
a-, AND circuit 24a13, etc.
While not input to the D terminal of the FF 24a16, as shown in FIG.
As shown in (b), the pulse signal B is the clock signal CLK.
Since it is turned on for three cycles of, the D- is connected via the AND circuit 24a12 and the AND circuit 24a13 as shown in FIG. 5C.
Input to D terminal of FF24a16.

The D-FF 24a16 is shown in FIG.
As shown in, D is turned on for three cycles of the clock signal CLK.
Only the pulse signal B input to the terminal is the clock signal CLK
The output signal is output from the Q terminal in synchronism with the above, and as a result, a filtering operation is performed to cut off the pulse signal A and the like that are turned on for less than three cycles of the clock signal CLK.

Next, the processing for changing the filter constant of the digital filter 24a of the remote slave station unit 24 in the first embodiment of the PLC remote I / O system thus configured will be described.

In this case, in the first embodiment, the filter constant is changed by transmitting the filter constant setting frame F from the remote master station device 1 side to the remote slave station unit 24 of the remote slave station device 2.

That is, as shown in FIG. 2, the filter constant transmitting section 15a of the remote master station unit 15 causes the address of the remote slave station unit 24 and a filter constant setting command for instructing to change the filter constant as shown in FIG. When,
A filter constant setting frame F in which the setting data of the filter constant to be changed is set is created and output via the communication control unit 15b.

In the remote slave station unit 24 of the remote slave station device 24, the communication controller 24 is connected via the connection cable 4.
c receives the filter constant setting frame F, and the filter constant data latch unit 24a3 of the input filter 24a.
The filter constant setting frame F is passed to.

The filter constant data latch section 24a3 is
The filter constant setting frame F is received, and the select signal SEL of the clock signal is received based on the setting data.
1 and 2 are sent to the clock selector 24a2.

The clock selector 24a2 receives the select signal SEL from the filter constant data latch section 24a3.
1 and 2, clock signals CLK having different frequencies
One clock signal CLK is selected from 1 to 4 and sent to the digital filter 24a1.

The digital filter 24a includes a clock signal CLK selected by the clock selector 24a2.
Is taken in and the input signal from the IN unit 22 is taken in using the clock signal CLK as a sampling clock to perform the filtering process as shown in FIG.

Then, the buffer 24b fetches and holds the input data filtered by the digital filter 24a1, and transmits the data to the remote master station unit 15 of the remote master station device 1 via the communication control section 24c.

Therefore, according to the first embodiment, since the filter constant of the input filter of the remote slave station device can be set from the remote master station unit of the remote master station device, the remote slave station unit side is able to set the filter constant one by one. Since it is not necessary to adjust or change the parameter, it is possible to significantly reduce the time and effort required for the filter constant setting process.

In the first embodiment, a filter constant transmitter for creating and transmitting the filter constant setting frame F based on the setting of the switch etc. is provided in the remote master station unit, but in the present invention, Not limited to this, the filter constant of the input filter may be set by setting and transmitting by a tool connected to the CPU unit or the like, or by setting and transmitting by executing the user program by the CPU unit.

In the first embodiment, the clock selector and the filter constant data latch unit are provided for each remote slave station unit, but the clock selector and the filter constant data latch unit are provided for the remote slave station. If a plurality of units are provided for each input point of the unit, the filter constant can be set for each point.

Further, when the remote master station unit or the remote slave station unit has a pulse catching function for holding a minute pulse, the pulse width is set by the filter constant setting frame F transmitted from the filter constant setting section. You may do it.

Next, the remote I / O of the PLC according to the present invention
A second embodiment of the O system will be described.

FIG. 6 shows a PLC remote I according to the present invention.
The configuration of the second embodiment of the / O system is shown in a simplified manner, and the CPU unit 11 and the remote master station unit (R
M) 15 'and a remote slave station unit (RT) 24',
It is shown by 32 '.

In the second embodiment, unlike the first embodiment, the remote slave station units 24 'and 32' may not be provided with an input filter, and the remote master station unit 1
The filter operation of the input filter is performed according to the polling interval from the 5'to the remote slave station units 24 'and 32', and the polling interval is set to the remote master station unit 15 '.
The input pulse width can be selected by changing the input pulse width.

That is, in the second embodiment, the remote master station unit 15 'has a polling interval setting unit 15a' for setting the polling interval based on the setting of the switch and the like.
Based on the polling interval set by the polling interval setting unit 15a ', the remote slave station units 24', 32 '
Etc., and a communication control unit 15b ′ that performs a filtering operation by performing polling communication.

The filter function according to the polling interval and the operation of changing the filter constant will be described with reference to the drawings.

FIG. 7 shows a concrete example of the filter operation in the second embodiment.

First, as shown in FIG. 7A, pulse data A and B are input to the input terminal IN0 of the remote slave station unit 24 '.
7B, the remote master station unit 15 'conducts polling communication with the remote slave station unit 24 and the like at a polling interval of 4 ms set by the polling interval setting unit 15a' as shown in FIG. 7B. I shall.

Then, in the remote master station unit 15 ', the communication control unit 15b' captures the pulse data captured by the remote slave station unit 24 'twice at every 4 ms polling timing. For this reason,
As shown in FIG. 7 (c), the communication control unit 15b 'cuts and does not capture the pulse data A because it is shorter than the polling interval of 4 ms, while the pulse data B is longer than the polling interval of 4 ms. Can be captured as

Then, the communication control unit 15b 'is configured as shown in FIG.
As shown in (d), only the input data “11” of the captured pulse data B is passed to the CPU unit 11 and the filtering operation is performed at the polling interval.

Further, if the polling interval setting section 15a 'changes the setting of the polling interval, the filter constant of the filter operation according to the polling interval can be changed,
Any input pulse width can be selected.

Therefore, according to the second embodiment, the filter operation is performed according to the polling interval from the remote master station unit to the remote slave station unit, and the polling interval is set by the remote master station unit, so that an arbitrary input pulse can be obtained. Since the width can be selected, it is not necessary to provide an input filter on the remote slave station unit or input unit, and there is no need to set filter constants on the remote slave station unit side, reducing the time and effort required to set the filter constants. can do.

If the polling interval is set for each remote slave station unit, the filter constant can be set for each remote slave station unit.

In the second embodiment, the polling interval setting unit for setting or changing the polling interval is provided in the remote master station unit. However, the present invention is not limited to this, and is connected to a CPU unit or the like. Setting by the tool and sending to the remote master unit, or C
The polling interval may be set or changed by setting by executing the user program by the PU unit and transmitting to the remote master station unit.

When the remote master station unit has a pulse catching function for holding a minute pulse, the pulse width is set or changed by executing a polling interval setting unit, a tool, or a user program as in the above case. The pulse catch width of the pulse catch function can be set or changed.

Next, the remote I / O of the PLC according to the present invention
A third embodiment of the O system will be described with reference to the drawings.

FIG. 8 shows a PLC remote I according to the present invention.
The configuration of the third embodiment of the I / O system is shown in a simplified manner. The CPU unit 11 and the remote master station unit (R
M) 15 "and remote slave station unit (RT) 24",
32 ''.

In the third embodiment, as in the second embodiment, the remote slave station units 24 "and 32" may not be provided with an input filter, but unlike the second embodiment. The polling interval from the remote master station unit 15 "to the remote slave station units 24" and 32 "is fixed, and the filter operation is performed by comparison with the reference number of times when the remote master station unit transfers data to the CPU unit. The filter constant is set and changed by setting and changing the reference number.

That is, in the third embodiment, the remote master station unit 15 '' has a reference number setting section 15a '' for setting the reference number based on the setting of switches and the like, and the remote slave station units 24 '', 32. When the count value is smaller than the reference number set by the reference number setting unit 15a, the input data is ignored, while the number of consecutive matches of the data input from In some cases, it has a communication controller 15b ″ for sending the input data to the CPU unit 11.

Next, with reference to the drawings, a description will be given of the filter operation by comparison with the reference number and the processing of changing the filter constant and the like in the third embodiment thus constructed.

FIG. 9 shows a concrete example of the filter operation in the third embodiment.

First, as shown in FIG. 9A, pulse data A and B are input to the input terminal IN0 of the remote slave station unit 24 ''.
Is input, and as shown in FIG. 9 (b), the remote master station unit 15 ″ has a fixed polling interval of 2 ms.
Is performing polling communication with the remote slave station unit 24 and the like.

Then, in the remote master station unit 15 '', the communication controller 15b '' inputs the pulse data A, B input to the remote slave station unit 24 '' at each polling timing as shown in FIG. 9C. Take in. That is, the communication control unit 15b ″ captures the pulse data A as “11” and the pulse data B as “111” data.

Then, the communication control unit 15b '' is based on the reference number of times (three times in this embodiment) set or changed by the reference number setting unit 15a ''. '' Counts the number of consecutive matches of the data input, and the count value is the reference number setting unit 15
If it is smaller than the reference number set by a '',
While the input data is ignored, the input data is sent to the CPU unit 11 when the number of times is equal to or greater than the reference number.

For this reason, the communication control unit 15b '' is configured as shown in FIG.
As shown in (d), the input data “1” of the pulse data A
In the case of 1 ”, since it is not continuous three times or more, it is considered as noise and cut and not passed to the CPU unit 11, while
Since the input data “111” of the pulse data B is continuous three times or more, the input data “111” is passed to the CPU unit 11 and the filtering operation is performed by comparison with the reference number of times.

Further, if the reference number setting unit 15a ″ changes the setting of the reference number, the filter constant of the filter operation by the comparison with the reference number in the communication control unit 15b ″ can be changed, and any input can be made. The pulse width can be selected.

Therefore, according to the third embodiment, the polling interval from the remote master station unit to the remote slave station unit is fixed, and the filtering operation is performed by comparing with the data reference number of times in the remote master station unit. Since the input pulse width can be selected by setting the reference number of times, it is not necessary to provide an input filter in the remote slave station unit or the input unit as in the second embodiment, and the remote slave station unit side is not required. It is not necessary to set the filter constant, and the labor of the filter constant setting process can be reduced.

In the third embodiment, the data communication between the remote master station unit and the remote slave station unit is explained by the polling communication system. However, the present invention is not limited to the polling communication system, and other A communication method such as a CSMA / CD communication method may be used.

Further, in the third embodiment, the remote master station unit has been described by providing the communication control section for performing the filtering operation by comparison with the reference number and the reference number setting section for setting the reference number. The invention is not limited to this, and these may be provided in the CPU unit, or only the function of the reference number setting unit is set by a tool connected to the CPU unit or the like and transmitted to the remote master station unit.
Alternatively, the setting may be performed by execution of the user program by the CPU unit and transmission to the remote master station unit.

Further, when the remote master station unit has a pulse catching function for holding a minute pulse, the pulse width can be set or changed by executing the polling interval setting unit, tool, or user program. With this, the pulse catch width of the pulse catch function can be set or changed.

[0075]

As described above, according to the invention described in claim 1, the CPU unit or the remote master station unit sets the filter constant of the input filter of the remote slave station unit to set an arbitrary input pulse width. Since there is no need to adjust or change the filter constants on the remote slave station side one by one, it is possible to greatly reduce the time and effort required for setting the filter constants.

According to the invention described in claim 2, CP
Since the U unit or the remote master station unit performs the filtering operation according to the polling interval from the remote master station unit to the remote slave station unit, and the arbitrary input pulse width can be selected by setting the polling interval, the remote unit It is not necessary to provide an input filter on the slave station unit or the input unit, and it is not necessary to set a filter constant on the remote slave station unit side, so that it is possible to reduce the time and effort for setting the filter constant.

According to the third aspect of the invention, the CPU unit or the remote master station unit counts the number of consecutive matches of the data input from the remote slave station unit, and if the count value is smaller than the reference number, the count value is input. 3. The invention according to claim 2, wherein, while ignoring the above-mentioned data, when the number of times of reference is greater than or equal to a reference number, the filter operation is performed so that an arbitrary input pulse width can be selected by setting the reference number of times. alike,
It is not necessary to provide an input filter on the remote slave station unit or the input unit, and it is not necessary to set a filter constant on the remote slave station unit side, so that the labor for setting the filter constant can be reduced.

Since the remote master station unit sets the filter constant of the input filter of the remote slave station unit so that an arbitrary input pulse width can be selected, the remote slave station device adjusts or changes the filter constant one by one. It is not necessary to do so, and it is possible to greatly reduce the trouble of setting processing of the filter constant.

According to the second aspect of the invention, the CP
Since the U unit or the remote master station unit performs the filtering operation according to the polling interval from the remote master station unit to the remote slave station unit, and the arbitrary input pulse width can be selected by setting the polling interval, the remote unit It is not necessary to provide an input filter on the slave station unit or the input unit, and it is not necessary to set a filter constant on the remote slave station unit side, so that it is possible to reduce the time and effort for setting the filter constant.

In the invention according to claim 3, the CPU unit or the remote master station unit counts the number of consecutive times of the data input from the remote slave station unit,
If the count value is smaller than the reference number, the input data is ignored, while if it is more than the reference number, the filter operation is performed by taking it in, and by setting the reference number, an arbitrary input pulse width is set. Since the selection is made possible, it is not necessary to provide an input filter to the remote slave station unit or the input unit, and it is not necessary to set a filter constant on the remote slave station unit side as in the invention according to claim 2. It is possible to reduce the trouble of setting the constant.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a PLC remote I / O system according to the present invention.

FIG. 2 is an explanatory diagram showing a first embodiment of a remote I / O system for a PLC according to the present invention.

FIG. 3 is an explanatory diagram showing a filter constant setting frame.

FIG. 4 is an explanatory diagram showing a configuration of a digital filter.

FIG. 5 is an explanatory diagram showing the operation of a digital filter.

FIG. 6 is an explanatory view showing a simplified second embodiment of the remote I / O system of the PLC according to the present invention.

FIG. 7 is an explanatory diagram showing a specific example of a filter operation in the second embodiment.

FIG. 8 is an explanatory view showing a simplified third embodiment of the PLC remote I / O system according to the present invention.

FIG. 9 is an explanatory diagram showing a specific example of a filter operation in the third embodiment.

[Explanation of symbols]

1 Remote Master Station Device 11 CPU Unit 13 Input Unit 14 Output Unit 15 Remote Master Station Unit 15a Filter Constant Transmitter (Filter Constant Transmitter) 15a 'Polling Interval Setting Unit (Polling Interval Setting Means) 15a''Reference Count Setting Unit ( 15b '' communication control unit (communication control means) 2 remote slave station device 23 input unit 24 output unit 24a input filter (filter means) 25 remote slave station unit 3 remote slave station device 31 input unit 32 remote slave Station unit

Claims (3)

[Claims] 1. A PLC remote I / O system comprising a remote master station unit connected to a CPU unit via a bus, and a remote slave station unit connected to the remote master station unit via a communication cable. Unit or remote master unit
While having a filter constant transmitting means for transmitting the filter constant of the input filter of the remote slave station unit, the remote slave station unit has a filter means for performing a filter operation based on the filter constant transmitted by the filter constant transmitting means. A PLC remote I / O system characterized by the following. 2. A remote master station unit connected to a CPU unit via a bus, and a remote slave station unit connected to the remote master station unit via a communication cable and performing data communication with the remote master station unit by polling communication. In the remote I / O system of PLC, the CPU unit or remote master station unit is
A PLC remote I / O system comprising: polling interval setting means for setting a polling interval from the remote master station unit to the remote slave station unit. 3. A PLC remote I / O system comprising a remote master station unit connected to the CPU unit via a bus and a remote slave station unit connected to the remote master station unit via a communication cable, wherein The unit or remote master station unit counts the number of consecutive matches of the data input from the remote slave station unit. If the count value is less than the reference number, the input data is ignored, while if it is more than the reference number. The remote I / O system of the PLC, characterized in that the communication control means for taking in the input data and the reference number setting means for setting the reference number of the communication control means.