JPS6336320A - Programmable controller - Google Patents

Abstract

PURPOSE:To prevent the titled controller from being influenced by generation of a service interruption, by providing a nonvolatile storage means, and a means for setting the programmable controller to an operating state which has been stored in the nonvolatile storage means. CONSTITUTION:When a power source is turned on to a programmable controller 1, a microcomputer 2 reads operation mode information from a RAM 4, decides whether the mode is an operation mode or not, and executes a sequence program for operating the programmable controller 1, at the time of the operation mode. Subsequently, whether there is an operation mode change request from a programming loader 7 or not is decided, and when there is the change request, the operation mode information which is requested is stored in the RAM 4. Even in case when a service interruption is generated in the course of executing the control procedure, since the operation mode information of the programmable controller is stored in the RAM 4, and this RAM is a nonvolatile memory, after the power is restored, the programmable controller 1 can be restored to the operation mode before the service interruption in accordance with said operation mode information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a programmable controller that restores an operating mode corresponding to the state before the power outage when power is restored after a power outage.

[Prior Art] Generally, in a programmable controller, the processor unit that performs arithmetic processing is not provided with an operation mode changeover switch for running and stopping, and when the power is turned on, it immediately enters the operating state, and by operating the keys on the programming loader, A device that switches between an operating state, a stopped state, and an operating state is known.

[Problems to be Solved by the Invention] However, with conventional programmable controllers of this type, if a power outage occurs while the controller is stopped, it will immediately go into operation when the power is restored, so it is difficult to connect external equipment to the programmable controller. , there was a problem that the external equipment would start moving.

Therefore, the purpose of the present invention is to solve such problems,
An object of the present invention is to provide a programmable controller that is not affected by the occurrence of a power outage.

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a nonvolatile controller that stores the current operating state of the programmable controller and stores the immediately previous operating state even when a power outage occurs. The present invention is characterized by comprising a storage means and a means for setting the programmable controller to the operating state stored in the non-volatile storage means at the time of recovery from the power outage.

[Function] In the present invention, operation mode information indicating whether the programmable controller is in an operating state or a stopped state is stored in a non-volatile memory that can retain its contents even when the programmable controller is stopped, and when the power is restored. At times, the programmable controller is restored to the same operating mode as before the power outage depending on the operating mode immediately before the power outage, so the programmable controller does not malfunction when the power is restored.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a configuration in an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a programmable controller (PC) according to the present invention, which includes an arithmetic processing unit (MPU) 2 that executes a sequence program and a control program shown in FIG.

Pct is a read-only memory (ROM) 3 that stores the sequence program and the above-mentioned control program, and a nonvolatile memory that stores the operating status of the programmable controller 1, such as a random access memory backed up by a battery (not shown). Memory (RAM) 4, interface for connecting to external peripheral devices 5. It has an interface 6 that connects to a loader 7.

FIG. 2 shows an example of a control procedure in an embodiment of the present invention.

In FIG. 2, when the programmable controller 1 is powered on, the microcomputer 2 reads operation mode information from the RAM 4 in step S1. Next, in step S2, it is determined whether the read operation mode information is a driving mode or not, and if not, the process proceeds to step S4.

When in the operation mode, a sequence program for operating the programmable controller 1 is executed in step S3. Next, in step S4, it is determined whether or not there is an operation mode change request from the programming loader 7, and if there is a change request, the requested operation mode information is stored in the RAM 4 in step S5, and the process proceeds to step S1. return. If there is no change request, the process returns to step S1 and this control procedure is repeatedly executed.

Even if a power outage occurs while this control procedure is being executed, the programmable controller's operating mode information will remain in RA.
Since this RAM is a nonvolatile memory, after the power is restored, the programmable controller 1 can be restored to the operating mode before the power outage according to the above-mentioned operating mode information.

[Effects of the Invention] As explained above, according to the present invention, when power is restored after a power outage, the programmable controller can be restored to the operating mode before the power outage, so even if a power outage occurs while the programmable controller is not operating. Even in such a case, there is no risk that the programmable controller will go into operation mode after the power is restored and the external equipment will operate, thereby achieving the effect that the safety of the programmable controller can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a configuration in an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of a control procedure in an embodiment of the present invention. 2nd Invention Chaos Ike 1 Libro...l'7 Figure 1: F Invention Implementation Flow Chart Figure 2

Claims (1)

[Scope of Claims] Nonvolatile storage means that stores the current operating state of the programmable controller and stores the immediately previous operating state even when a power outage occurs; and means for setting the programmable controller to an operating state.