JPH01280804A - Controller - Google Patents

Abstract

PURPOSE:To detect the overcurrent flowing into a motor by obtaining the load current value from a motor in a numerical controller (NC) to write it into a shared memory and then reading said current value into a PLC via a data input/output part. CONSTITUTION:An NC1 has a shared memory 4 with a programmable logic controller PLC12. A data input/output part is added to the NC1 to perform communication by the memory 4 among the information required for both the NC1 and PLC12 for control, the working information owned by the NC1, and the actual load current value of a driving motor for a machine tool. The PLC12 is connected to said data input/output part with a parallel bus 21. Then the load current of a motor 10 is detected by a detector 11 and read by a drive control part 9. Then this load current is read by a CPU 2 and written into the memory 4 after an arithmetic operation. Then the load current value of the motor 10 is read out of the PLC12 via the memory 4. Thus it is possible to detect the overcurrent flowing to the motor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device having an NC and a PLC.

[Conventional technology]

FIG. 4 is a diagram showing a conventional control device.

In the figure, (1) is NC, (2) is NC (1)Q)C
PU, (3) is a storage unit that temporarily stores machining information (nitrogram, coordinate values, speed, etc.), (4) is N
Shared memory used to exchange information between O(1) and PLC03, (5)
i! I communication enabled η>PLCυ−shared memory (4
); (6) a switching unit that enables or switches communication between
7) is an interrupt control unit, (8) the head is an interface for parallel bus I21J control, (9) is a moving layer of the machine tool (not shown), calculates the speed, and outputs it to the motor αO that drives the machine tool. 13 is the CPU of the PLCIE
, 1 is a memory unit which stores a mechanical control sequence program (memory part, , (to) sets the control mood to PLC [12 and displays it in the setting display section, 0!J is connected to the setting display section (to) and is stored on tape 4 via the setting display section (g). This is an input section for inputting processing information.

The operation of receiving information between the groove forming NC (1) and the PLC 03 as described above will be explained. First, the case of writing processing information to NC(1) will be explained based on FIG. 2.

When the processing information write signal is input to PLCQ2 (steel knob 30), PLC! (3) sends an interrupt signal to the interrupt control unit (6) via the interface O9, parallel bus CD, and interface (8) (step 31);

The interrupt control unit (6) interrupts the CPU (2) using an interrupt signal (stave 32). When the CPU (2) receives the interrupt, if the writing is not completed (Step 33),
Send a switching signal to the switching unit (5) and switch the switching unit (5) to the PLCC
The switching section is moved to the IZ side (step 34). Next, the CPU
(2) Send an interrupt signal indicating that the CPU is ready to the interrupt control unit (7) and issue an interrupt to the PLCO 2 from the interrupt control unit (7) (Step 35). When the PLCU receives an interrupt signal indicating that the CPU is ready (step 36), the input section Q9
Read the machining information from the setting display section (to) interface Lewis α9, parallel tool bus c! 1), Interface (
8), the processing information is stored in the shared memory (4) (step 37). When writing of processing information to the shared memory (4) is completed (Step 38), C! P
An interrupt signal indicating the completion of writing is sent to U(2) via the interrupt control unit (6) (step 32), and then the write operation is completed (step 39). On the other hand, CPU (2) is a PLC
When receiving the write completion interrupt signal from Q2 (step 38), the switching unit (5) is switched to the CPU (2) side (step 40). After that, the CPU (2) uses the shared memory (
The processing information written in step 4) is read into the storage section (3) (Step 41), and the process is completed (Step 42). M1
When the reading of processing information into the storage section (3) is completed, the CPU (2) sends an interrupt signal to the PLCa2 via the interrupt control section (7) and displays the completion of reading on the setting display section (to). I can do it.

Next, a case in which the PLCU reads out the contents of the shared memory (4) will be described with reference to FIG. A read request signal is input to PLC (2) (step 51).

A read request interrupt is applied to the interrupt control unit (6) of the NC (1) (steer knob 52). The interrupt signal from the interrupt control unit (6) is sent to the C'PU (2) (the stay knob 53
), the CPU (2) determines whether or not reading of processing information from the shared memo 1 (4) has been completed.
If the reading is not completed, the CPU (2) writes the processing information to the shared memory (4) (Step 55).

In this case, the processing information to be written to the shared memory (4) includes, for example, the current coordinate value and speed, which are stored in the drive control unit (9).
is calculated by reading from the detector α, and this is calculated by the CPU (
2) is reading and writing to the shared memory (4). When the writing is completed, the CPU (2) releases the shared memory (4) to the PLCa2 side, and then switches the switching unit (5) to the PLC ■ side (Step 56), and then releases the shared memory (4) from the CPU (2). An interrupt signal indicating completion of preparation is sent to the PLCC 2 via the interrupt control unit (7) (Step 57). When PLCQ2 receives the preparation completion interrupt signal (step 58), PLCQ2 stores the shared memory (4
) to read out the contents of step 59), and when the reading is completed (step 0), sends an interrupt signal indicating successive completion to the CPU (2) again via the interrupt control unit (6). Send (Step 1, B53). At the same time, the read operation is completed...
Pro 1), control the machine αη based on the new data.

On the other hand, when the CPU (2) receives an interrupt signal indicating the completion of reading from the PLCa2 (steer knob 54), the CPU (2) switches the switching unit (5) to C.
Switch to the PU (2) side (Step 1 Pro 2) and complete (Step 1 Pro 8).

[Problem to be solved by the invention]

In conventional control devices, the processing information written by the NC in the shared memory includes current coordinate values, speed, etc., but does not include current values indicating the load of the motor that drives the machine. However, if an excessive current flows through the motor l and the motor stops due to the protection circuit fζ, the PLC cannot detect the cause of the overcurrent and it takes time to investigate the cause. It's one thing.

The present invention solves these problems.
r: The purpose of the present invention is to obtain a control device that can detect this with a PLC when an excessive current flows in a motor.

[Means to solve the problem]

In the control device according to the present invention, the NC has a shared memory with the PLC, and the shared memory allows information necessary for the control of the NC and the PLC and processing information held by the NC to identify the motor driving the machine tool. A data input/output section for transmitting actual load current values is provided in the NC, and the data input/output section and the PLC are connected via a parallel bus.

[Effect]

In the present invention, a load current value is obtained from the motor in the NC, is stored in the shared memory, and is read into the PLC via the data input/output section and the parallel bus, so that one current flows to the motor. Be able to detect excessive current.

[Embodiments of the invention]

FIG. 1 is a Brolik diagram showing one embodiment of the present invention. In the figure, everything except (4) is shown in FIG. 4 and is the same as the conventional example, so only (4) will be explained. (4) is a shared memory, but the difference from the conventional example is the motor load current value (4b
) is added to the conventional example. Motor load current value (
4bj is a current value indicating the actual load currently applied to the motor.

Regarding the operation of the present invention, only the operation of writing the motor load ymm value to the shared memory (4) will be explained. Other operations are the same as in the conventional example, and will therefore be omitted. In the conventional example, writing of motor load (current value) is done by CPU (2) writing machining information to shared memory (4).
) in the same way. That is, scouring is performed at step 55 in FIG. The motor load current value to be written is the current coordinate value in the conventional example.

Find it in the same way as finding the speed. That is, the load current of the motor αO is detected by the detector αυ, read and calculated by the drive control unit (9), and then read by the CPU (2) and written into the shared memory (4).

〔Effect of the invention〕

According to the present invention, the actual load current value applied to the motor can be read out from the PLC via the shared memory, so if an excessive current is flowing in the motor, the PLC can detect it and, for example, It is possible to immediately notify the operator of the situation by displaying an alarm and outputting a 1-stiff alarm. Furthermore, time-series changes in the morph load current can be recorded on the PLC side and can be used as data for fault diagnosis.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of the present invention, the second factor is a flowchart showing processing information read processing of the embodiment and conventional example, and FIG. 3 shows processing information reading processing of the embodiment and conventional example. FIG. 4 is a professional riff diagram showing a conventional example.

Claims (1)

[Claims] In a control device having a numerical control device (hereinafter referred to as NC) and a programmable logic controller (hereinafter referred to as PLC) connected to the NC, the PLC is connected to the NC.
The NC and the PLC communicate information necessary for control, processing information possessed by the NC, and the actual load current value of the motor driving the machine tool through the shared memory. a data input/output unit is provided in the NC,
A control device characterized in that the data input/output section and the PLC are connected via a parallel bus.