The main task of the equipment operation monitoring system is to independently fix the equipment useful operation time and the ability to control the equipment operation efficiency in an automated mode without human intervention. The second task of the monitoring system is to collect statistical data on the causes of equipment downtime and makes it possible to analyze the causes of productivity losses, develop and im-plement corrective measures to eliminate them [1][2][3]. The third task is analytical support in making operational decisions on the management of production processes [4][5][6][7].
Functioning in the infocommunication network of an enterprise, the security requirements for the monitoring system used become more important [4; 7-10].
Among the main requirements for software and hardware systems for planning and monitoring production processes, the following can be distinguished: ─ The monitoring system software must be located on the enterprise server; ─ The server part of the monitoring system must be located on the servers of the enterprise; ─ The monitoring system should be able to distribute access rights among employees; ─ The total number of users connected to the system should not be limited; ─ Data should be accumulated on the server without overwriting the previously recorded ones. The data must be stored indefinitely; ─ The system should return the requested data upon request from the client application or from the web client.
Also among the requirements are real-time monitoring and possible integration with other enterprise systems.
Computer equipment and critical network equipment should be placed in lockable cabinets that restrict access to unauthorized persons; when the doors of the industrial and technological complex cabinets are opened, an alarm should be displayed at the operator's workplace. System blocks of Automated Work Places (AWPs) of operators should be placed in lockable cabinets. Firewalls must be provided at the border of machines with a Data Exchange Server (DES). As a firewall, a specialized software and hardware FireWall (FW) should be used that controls all information exchange with the DES. Only the ports and services required to access these machines should be open on the firewall. All other ports and services must be blocked.
A demilitarized zone must be applied between the machines and the Local Area Network (LAN).
Direct access from the corporate network to the LAN of the machines should be excluded -access should be carried out only through the DES (the machines must transmit data by referring to the DES). The rules for adjusting the FW must be agreed and documented.
On the LAN of machines, the following should be prohibited:
─ remote access to machine tools for technical support of system and applied software (SW); ─ access to machine tools from public information networks, for example, the Internet; ─ Internet access services and e-mail; ─ direct access to the corporate network.
During implementation, specialists need to provide all the necessary equipment (including cabinets, cables) and software for transferring parameters from machines to the monitoring center. The list of parameters that need to be transferred are developed at the stage of collection of initial data and are agreed with the specialists of the enterprise.
The section of the project documentation on information security should contain:
─ description of the object of protection; ─ information security threat model; ─ model of a potential illegal intruder; ─ description of the technical means complex; ─ solutions for ensuring information security, including solutions for access control, security audit, protection of machine storage media, ensuring integrity, ensuring availability, anti-virus protection, protecting the automated system and its components, etc.; ─ specifications of equipment and software for the information security subsystem.
All decisions must be sufficient and justified in accordance with the results obtained in the process of analyzing current threats to information security and potential illegal intruder.
The graphic part of the section should include:
─ structural diagram of a technical means complex for information protection, superimposed on the corresponding diagrams of the information and technological infrastructure of the object, communication systems, etc. The diagram should clearly highlight the computer equipment and information security equipment installed or modified within the framework of the project; ─ diagram of information interaction of machine tools with external systems; ─ diagram of the functional structure of the information security subsystem.
As a result, the main requirements for the safety of the industrial equipment monitoring system were formulated.
Ensuring safety when working in the equipment planning and monitoring system is carried out in the following three areas. 1) User (client) authorization:
─ Only a user (client) with an MS Windows account and access to the enterprise information network can start the Dispatcher's AWP; ─ The user works only with the interface of the Dispatcher's AWP, which does not have any functionality to influence the operation of both equipment and the monitoring system; ─ In the basic configuration, user authentication is disabled. If an unauthorized person has access to the user's computer, the Dispatcher's AWP can be launched; ─ If user authentication is enabled (with an MS Windows account), when starting the Dispatcher's AWP, the client's rights to work with the monitoring system are checked, and in the absence of such rights, access to the Dispatcher's AWP is not possible; ─ To work with the monitoring unit, the operator must be authorized, while he has no opportunity to influence the operation of the equipment through the monitoring system.
2) Server authorization: ─ Only the system administrator has access to the server; ─ When working with the Dispatcher's AWP, the user (client) has no opportunity to influence the operation of both the equipment and the server; ─ Only monitoring services operate on the server, which are not able to influence the operation of the equipment.
3) Information flows in the monitoring system: ─ The information flow from the server to the machine is a request for the state of the equipment using the library of the equipment control system without the possibility of controlling the equipment; ─ The information flow from the machine to the server is the response to the system's request for the equipment status; ─ The information flow from the monitoring unit to the server is the result of the operator's actions on the monitoring unit (authorization, entering the reason for downtime, etc.) without the possibility of controlling the equipment; ─ The information flow from the server to the monitoring unit is confirmation or non-confirmation of operator authorization; ─ The information flow from the Dispatcher's AWP to the server is one request (at the first start of the Dispatcher's AWP) about the state of the equipment in real time without the possibility of controlling the equipment and a request for generating a report; ─ The information flow from the server to the Dispatcher's AWP is the result of a change in the state of the equipment in real time and a response to a user's request for generating a report. Set-up takes quite a long time, which is 30 % of the total time, or more than half of the processing time. Consequently, reducing the time of production losses when setting up equipment can significantly increase the proportion of processing.
The general diagram of data transmission in the system is shown in Figure 1. Noting the data transfer structure shown in Figure 1, the parameters of the generated indicators, summarized in Table 1, should be highlighted.
The values of the indicators indicated in Table 3 allow to generate various tabular and graphical reports indicating the dynamics of key values. From the values of technological modes (feed, speed), economic indicators are identified, which are set individually for each type of equipment.
If the safety requirements of the equipment monitoring system are met, the managers and specialists of the enterprise receive objective data for making management decisions.
The management assesses the Overall Equipment Efficiency (OEE), monitors the dynamic indicators of the equipment efficiency, receives data on the onset of a condition or violation of technological modes (sms, e-mail).
The technological service receives data on the equipment operation for the selected period in the context of production-equipment-operator-detail-operation-modes of processing-machine time-reasons for stops-program frames-tool, which was used for processing. In addition, it is possible to track the change in the NC program, the duration of stops during NC execution, the NC execution time, pauses between NC starts, program blocks.
The equipment maintenance service is promptly informed about the number, type and frequency of equipment breakdowns.