JP2002330121A - Control unit and network servo control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synchronously control a system having network servos with more axes than one transmission module can control. SOLUTION: Transmission modules 1 and 2 each have a synchronous circuit that forms a synchronous signal synchronous with a high-speed scan signal inputted from a CPU module 3. By generating a transmission interruption to coincide with generation of the synchronous signal, the modules 1 and 2 synchronize the transmission cycle, based on which an instruction is outputted to network servos 5 and 6, with the cycle of the high-speed scan signal. Thus synchronous control on the network servos 5 and 6 is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control unit for controlling a plurality of network servos, and more particularly to a network servo control method for controlling a network servo using the control unit.

[0002]

2. Description of the Related Art When controlling a system composed of a plurality of servos, a control unit composed of a CPU module and a transmission module connected to the CPU module by a system bus is used. In this control unit, the transmission module is a CPU
Controls a plurality of network servos based on command output from the module.

However, since the number of network servos that can be controlled by one transmission module is limited,
When controlling a system that requires a certain number of network servos or more, a plurality of transmission modules are required. FIG. 7 shows a control unit using such a plurality of transmission modules.

This conventional control unit is shown in FIG.
As shown in (1), it comprises a CPU module 3 and transmission modules 101 and 102, and controls network servo groups 5 and 6.

[0005] The CPU module 3 generates a command output for each network servo and outputs it to the transmission modules 101 and 102 via the system bus 4. Further, the CPU module 3 generates a high-speed scan signal having a constant period and outputs the signal to the transmission modules 101 and 102.

[0006] The transmission modules 101 and 102 are connected to the CPU module 3 by a system bus 4.
The command output output from the PU module 3 is fetched at each high-speed scan signal timing, and the network servo groups 5 and 6 are controlled based on the command output.

[0007] Such a plurality of transmission modules 101,
In the conventional control unit having the control unit 102, the transmission modules 101 and 102 can respectively perform synchronous control of connected network servos. That is, in the conventional example shown in FIG. 7, the transmission module 1 can perform the synchronization control of the network servo group 5, and the transmission module 2 can perform the synchronization control of the network servo group 6. .

However, in this conventional control unit, each of the transmission modules 101 and 102 outputs a command to each of the network servo groups 5 and 6 connected at a transmission cycle based on its own clock. Therefore, as shown in FIG.
Due to the difference in the output timing of the command to the network servo between the transmission modules 1 and 102, the command arrival time to the network servo connected to each transmission module varies at the maximum by the transmission cycle of the transmission modules 101 and 102. Will occur.

Therefore, in the conventional control unit, when controlling a multi-axis network servo using a plurality of transmission modules, all the network servos cannot be synchronously controlled. That is, the conventional control unit cannot control all network servos synchronously with a system having network servos exceeding the number of axes that can be controlled by one transmission module.

[0010]

In the conventional control unit described above, it is not possible to perform synchronous control of a network servo group extending over a plurality of transmission modules.
There was a problem that the network servo synchronization control could be performed only up to the number of axes controllable by one transmission module.

An object of the present invention is to provide a control unit capable of performing synchronous control even for a system having network servos exceeding the number of axes that can be controlled by one transmission module.

[0012]

In order to achieve the above object, the present invention provides a control unit for controlling a plurality of network servos, comprising: a CPU module for outputting a high-speed scan signal having a constant period; , The C
A synchronization circuit that generates a synchronization signal synchronized with the high-speed scan signal input from the PU module, a transmission counter that clears a count value at a timing when the synchronization signal is generated, and a transmission counter that generates a transmission interrupt; And a transmission driver configured to output a command to each of the network servos according to a transmission cycle based on the transmission interruption.

According to the control unit of the present invention,
The timing at which the command output output from the CPU module for each high-speed scan is output to the network servo as a command by the plurality of transmission modules becomes the same timing as the high-speed scan signal. Therefore, the command arrival times from the plurality of transmission modules to the network servo group are the same, and the synchronous control of the network servo group can be performed by the plurality of transmission modules.

In another control unit according to the present invention, each of the transmission modules further includes a frequency dividing circuit for dividing a synchronous signal generated by the synchronous circuit at a preset frequency dividing ratio.

According to the present invention, even when the period of the high-speed scan signal from the CPU module is shorter than the transmission period of the transmission module, the period of the high-speed scan signal can be divided to match the transmission period of each transmission module. Therefore, synchronization control can be performed by synchronizing the transmission cycle between the transmission modules.

Further, the frequency dividing circuit includes a frequency dividing setting register in which a frequency dividing ratio is set in advance, and a frequency dividing ratio of the synchronous signal generated by the synchronous circuit based on the frequency dividing ratio set in the frequency dividing setting register. A frequency divider for dividing the frequency may be used.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a control unit according to one embodiment of the present invention.

The control unit of the present embodiment has a C
It is composed of a PU module 3, transmission modules 1 and 2, and a system bus 4, and network servo groups 5 and 6
Is controlled. In FIG. 1, the same components as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the system 7 composed of the network servo groups 5 and 6 will be described as a system that requires multi-axis synchronous control.

The transmission module 1 is, as shown in FIG.
Synchronizing circuit 11, frequency dividing circuit 12, transmission counter 13
And a transmission driver 14. The frequency dividing circuit 12 includes a frequency divider 8 and a frequency dividing setting register 9. Here, the configuration of the transmission module 1 will be described, but since the configuration of the transmission module 2 is the same as the configuration of the transmission module 1, the redundant description will be omitted.

The synchronization circuit 11 generates a synchronization signal synchronized with the high-speed scan signal input from the CPU module 3. The dividing circuit 12 divides the synchronization signal generated by the synchronizing circuit 11 by a preset dividing ratio. The transmission counter 13 clears the count value at the timing when the divided synchronization signal from the frequency dividing circuit 12 is generated, and causes the transmission driver 14 to generate a transmission interrupt.

The transmission driver 14 outputs a command to the network servo group 5 at a transmission cycle based on a transmission interrupt generated by the transmission counter 13.

The frequency division setting register 9 is a register for setting a frequency division ratio of 1 to 1 / N (N is an integer of 1 or more) in advance. The frequency divider 8 divides the frequency of the synchronization signal generated by the synchronization circuit 11 according to the frequency division ratio set in the frequency division setting register 9.

Next, the operation of the control unit of this embodiment will be described in detail with reference to the drawings.

First, a case where the cycle of the high-speed scan signal output from the CPU module 3 is equal to the transmission cycle of each of the transmission modules 1 and 2 will be described.

In this case, the frequency division setting register 9 contains
A division ratio of 1 is set in advance. Therefore, the frequency divider 8 outputs the synchronization signal from the synchronization circuit 11 to the transmission counter 13 without dividing the frequency.

In a state where such a setting is made,
When a high-speed scan signal from the CPU module 3 is input to the transmission modules 1 and 2 via the system bus 4,
In the synchronization circuit 11 in each of the transmission modules 1 and 2, C
A synchronization signal synchronized with the high-speed scan signal input from the PU module 3 is generated. Then, the synchronization signal generated by the synchronization circuit 11 is directly input to the transmission counter 13 without being divided by the frequency divider 8,
The count value is cleared at the timing when the frequency-divided synchronizing signal from the frequency dividing circuit 12 is generated.
Generates a transmission interrupt. Therefore, the transmission drivers 14 of the transmission modules 1 and 2 output commands to the network servo groups 5 and 6 at a transmission cycle based on the transmission interrupt generated by the transmission counter 13, respectively.

FIG. 3 shows the relationship between the high-speed scan signal and the transmission cycle when the cycle of the high-speed scan signal output from the CPU module 3 and the transmission cycle of each of the transmission modules 1 and 2 are equal.

As described above, in the control unit of this embodiment, the commands output from the transmission modules 1 and 2 to the network servo groups 5 and 6 are synchronized with the high-speed scan signals.

Next, a case where the cycle of the high-speed scan signal output from the CPU module 3 and the transmission cycle of each of the transmission modules 1 and 2 are different will be described.

In this case, the period of the high-speed scan signal may be longer or shorter than the transmission period.
The case where the cycle of the high-speed scan signal output from the CPU module 3 is longer than the transmission cycle of each of the transmission modules 1 and 2 will be described.

In this case, the frequency division ratio of the frequency divider 8 is set to 1. Therefore, the frequency divider 8 outputs the synchronization signal from the synchronization circuit 11 to the transmission counter 13 without dividing the frequency. FIG. 4 shows the relationship between the high-speed scan signal and the transmission cycle in this case. FIG. 4 shows a case where the cycle of the high-speed scan signal is twice the transmission cycle. Even in such a case, when the synchronization signal is generated, the count value of the transmission counter 13 is cleared and a transmission interrupt is generated, so that the synchronization signal and the transmission cycle are synchronized. However, it is assumed that the cycle of the high-speed scan signal is an integral multiple of the transmission cycle.

Next, a case where the cycle of the high-speed scan signal output from the CPU module 3 is shorter than the transmission cycle of each of the transmission modules 1 and 2 will be described. In this case, the cycle of the high-speed scan signal is 1 / integer of the transmission cycle.
(1 / N: N is an integer of 1 or more).

In this case, the frequency division ratio of the frequency divider 8 is 1 / N
, The synchronization signal divided at a rate of one while the high-speed scan signal is output N times is input to the transmission counter 13. FIG. 5 shows the relationship between the high-speed scan signal and the transmission cycle in this case. FIG. 5 shows a case where the cycle of the high-speed scan signal is half the transmission cycle.

As described above, by clearing the transmission counter 13 and generating a transmission interrupt at the timing when the synchronization signal generated by dividing the high-speed scan signal by 1 / N is generated,
The transmission cycle of the high-speed scan signal and the transmission modules 1 and 2 are synchronized.

As described above, according to the control unit of this embodiment, as shown in FIG. 6, a plurality of transmission modules 1 and 2 transmit a command output output from the CPU module 3 for each high-speed scan to the network. The timing at which a command is output to the servo groups 5 and 6 is the same as that of the high-speed scan signal. Therefore, the command arrival times from the plurality of transmission modules 1 and 2 to the network servo groups 5 and 6 are the same, and the synchronization control of the network servo groups 5 and 6 can be performed by the plurality of transmission modules 1 and 2.

That is, by providing the frequency dividing circuit 12 between the synchronization circuit 11 and the transmission counter 13, even if the period of the high-speed scan signal from the CPU module 3 is shorter than the transmission period of the transmission modules 1 and 2, The period of the high-speed scan signal can be divided to match the transmission period in each of the transmission modules 1 and 2.

If the cycle of the high-speed scan signal is the same as the transmission cycle in each of the transmission modules 1 and 2, or if the cycle of the high-speed scan signal is longer than the transmission cycle in each of the transmission modules 1 and 2, One, two
Therefore, the frequency dividing circuit 12 can be omitted.

[0040]

As described above, according to the present invention,
Since the transmission cycle of each transmission module is synchronized with the high-speed scan signal output from the CPU module, synchronization control is performed even for a system having network servos exceeding the number of axes that can be controlled by one transmission module. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a control unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a transmission module 1 in FIG.

FIG. 3 is a diagram illustrating a relationship between a high-speed scan signal and a transmission cycle when the cycle of the high-speed scan signal output from the CPU module 3 is equal to the transmission cycle of each of the transmission modules 1 and 2;

FIG. 4 is a diagram illustrating a relationship between a high-speed scan signal and a transmission cycle when the cycle of the high-speed scan signal output from the CPU module 3 is longer than the transmission cycle of each of the transmission modules 1 and 2;

FIG. 5 is a diagram illustrating a relationship between the high-speed scan signal and the transmission cycle when the cycle of the high-speed scan signal output from the CPU module 3 is shorter than the transmission cycle of each of the transmission modules 1 and 2;

FIG. 6 is a diagram illustrating a relationship between a cycle of a high-speed scan signal output from the CPU module 3 and a transmission cycle of each of the transmission modules 1 and 2;

FIG. 7 is a block diagram showing a configuration of a conventional control unit.

8 is a diagram showing a relationship between a high-speed scan signal in the control unit shown in FIG. 7 and transmission synchronization of the transmission modules 101 and 102.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 2 Transmission module 3 CPU module 4 System bus 5, 6 Network servo group 7 System 8 Divider 9 Dividing setting register 11 Synchronous circuit 12 Dividing circuit 13 Transmission counter 14 Transmission driver 101, 102 Transmission module

Claims (5)

[Claims] 1. A control unit for controlling a plurality of network servos, comprising: a CPU module outputting a high-speed scan signal having a constant period; and a synchronizing signal synchronized with the high-speed scan signal input from the CPU module. A synchronization circuit that generates a transmission signal, a count value is cleared at a timing when the synchronization signal is generated, a transmission counter that generates a transmission interrupt, and a transmission cycle based on the transmission interrupt generated by the transmission counter. And a transmission driver configured to output a command to the control unit. 2. The control unit according to claim 1, wherein each of the transmission modules further includes a frequency divider that divides a synchronization signal generated by the synchronization circuit by a preset division ratio. 3. The frequency dividing circuit according to claim 1, wherein: a frequency dividing setting register in which a frequency dividing ratio is preset; and a frequency dividing ratio set in the frequency dividing setting register.
3. The control unit according to claim 2, further comprising a frequency divider that divides a frequency of the synchronization signal generated by the synchronization circuit. 4. A network servo control method using a control unit for controlling a plurality of network servos, the method comprising: generating a synchronization signal synchronized with a high-speed scan signal input from a CPU module; A network servo control method, comprising: generating a transmission interrupt at a timing at which the transmission interrupt occurs; and outputting a command to each of the network servos at a transmission cycle based on the transmission interrupt. 5. The network servo control method according to claim 4, further comprising the step of dividing the synchronization signal by a preset division ratio.