Black Box for Machine Tools; Based on Open CNC Architecture Control Systems

ACEEE Int. J. on Control System and Instrumentation, Vol. 03, No. 01, Feb 2012

Black Box for Machine Tools; Based on Open CNC
Architecture Control Systems
Atul Gupta1 and Venu Uppuluri Srinivasa2
1,2
Santerno India Design Center, Gigaspace, Building Beta-1,
Third floor, Office No. 301, Viman Nagar, Pune, M.H, India
1
Email: atulgupta2006@gmail.com,
2
Email: venuuppuluri@gmail.com

Abstract—Most computer numerical control (CNC) systems Environment. Presently BlackBox is actively used in Aircraft
are closed for users. Engineers typically can only program the and Automobile industry.
machine, nothing more. it cannot be freely modified by the
user. The introduction of open architecture philosophy A. BlackBox in Aircraft’s Industry
propitiated the evolution of a new generation of numeric “Black Box”[8] the aircraft’s flight data recorder (FDR)
controllers. This brought the conventional CNC technology and cockpit voice recorder (CVR) i.e. recording the flight
to the standard PC microcomputer. As a consequence, the
crew’s conversation on an airplane and of protecting that
characteristics of the CNC (positioning) and the micro
recording in the event of a crash or fire. The purpose of the
computer (easy of programming, system configuration, network
communication etc) are combined. There are also a number Black Box was to help identify the reasons for a plane crash.
of commercially available OAC (Open Architecture Airplanes are equipped with sensors that gather data. There
controllers) (e.g. MDSI, Fanuc, Okuma, Siemens). There are sensors that detect acceleration, airspeed, altitude, flap
are also a number of efforts at developing OAC standards [1- settings, outside temperature, cabin temperature and
4]. This paper uses Siemens [5] OAC to build the unique pressure, engine performance and more. Magnetic-tape
BlackBox for machine tool industry. This new technology in recorders can track about 100 parameters, while solid-state
machine tool industry helps us in understanding the cause of recorders can track more than 700 in larger aircraft. Data from
crash or malfunctioning of machine or machine health by
both the CVR and FDR is stored on stacked memory boards
means of debugging the critical machine data such as Spindle
inside the crash-survivable memory unit (CSMU). The memory
Speed, Axis positions, Feed rates, Type of Tool used etc which
are facilitated by this application just before the crash and boards have enough digital storage space to accommodate
same can be accessed remotely via Internet/ Ethernet. This two hours of audio data for CVRs and 25 hours of flight data
application is successfully intergraded and tested with actual for FDRs. The Black Box was invented in 1953 and in
Machine. production by 1957. The first ones were painted bright red or
orange to make them easier to find after a crash.
Index Terms—CNC, OAC, Machine Tool, BlackBox, HMI, PLC
B. BlackBox in Aircraft’s Industry
I. INTRODUCTION Open, Modular Architecture controllers are also required
in automotive industry [9]. In Automobile, BlackBox or Event
Over the last 50 years there have been many
Data Recorder (EDR)[10] module is a part of the air bag
developments in CNC manufacturing. These advances make
sensing system, stores information in the few seconds before
today’s CNC technology completely unrecognizable from
a car sensor identifies a crash and fires the air bags. EDR can
their early NC ancestors. The need for a new and vendor
collect the crash data from the air bag SDM (Sensing and
neutral open CNC architecture was emerging at many places
diagnostic module) such as speed, whether the seatbelts are
around the world. One of the most important works was done
fastened, and whether the driver hit the brakes before a
from 1992 within the frame of the European project named
collision. After a collision, the black box contains a record of
OSAC. Similar efforts are going on in Japan named OSEC
what was happening in the last seconds before the impact.
under the IROFA Consortium and in the U.S. within the OMAC
Data is permanently written on the EEPROM chip inside the
projects where many earlier American research results were
airbag SDM module. Packed in a small unbreakable, shock
collected.
and water proof container.
To meet the requirements of these new machines,
Air bag SDMs do not look at vehicle speed to determine
controllers have evolved from the early memory less
an air bag deployment command. The airbag SDM looks for
controllers to modern open-architecture PC based CNCs [6-
a change in acceleration on the vehicle ‘X’ axis to determine
7]. In combination with these advances, programming
deployment criteria. So technically, car could be stopped or
methods have progressed to take advantage of the new
moving very slowly, be in an accident event, and deploy the
processes and controller capabilities. Making advantage of
air bags. A sensor mounted on the front of the vehicle
OAC, concept of BlackBox is also implemented for Machine
supplies an input signal to the SDM. Almost all vehicles sold
Tool Industry as a core application by means of high-level
in North America since 1997 are collecting vehicle crash data.
language platform tools interfaced with OAC in PC
These include Toyota, Mercedes Benz, and Mitsubishi
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vehicles to name a few. Currently, only GM, Ford, and Chrysler measurements.
have released the crash data. 3) It must have the ability to obtain current feed rate in real
time as well as real time changes in the process, such as tool
II. OPEN CNC ARCHITECTURE FOR MACHINE T OOL no., tool wear, M code, G code etc.
4) Application programs must be able to run on the PC while
A. Specification of an Open Architecture System
the NC machine is running, to pass sensor and position
An Open Architecture Controller should be flexible in information to the programs model in a timely fashion.
hardware as it is in software for all control levels (Wright et
al., 1996) [11]. An Open Architecture Controller must be B. Hardware Components
standard to allow hardware and software development by A schematic of the hardware components is shown in Fig
any engineer or technician, and its integration with other 1.
controllers, cell control systems and high level planning  CNC Machine: NCU, the central processing unit of
systems (Schofield, 1996) [12]. the 840D controller. It contains the NC-CPU and the
The machine tool open controller should permit the PLC-CPU. It executes the NC program and maintains
integration of independent application program modules, communication with the peripherals via numerous
control algorithms, sensor and computer hardware developed interfaces like MPI bus, Profibus DP I/O
by different manufactures (Pritschow et al., 1993)[13]. An  PC Computer: Pentium III 700Mhz or higher, 256 Mb
Open System allows to program in several platforms that RAM, Ethernet connection, MPI board (for online
interact with other application systems. Some specifications testing) One advantage of using the SIEMENS Open-
of an open architecture system are (Miles, 1998) (Oshiro, CNC is that it is easy and relatively inexpensive to
1998) [14] upgrade standard computer components with faster
 Interaction: due to communication of standard data processing and more memory.
semantics;  Data Acquisition Board: Siemens makes PLC S7300
 Interoperability: same component function by supports complex applications with greater number
different manufacturer; of I/O points with modular and expandable
 Portability: the easy with which application software capabilities.
can be transferred from one environment to another.  Spindle Sensor: Spindle is equipped with
 Scalability: system ability to increase or to decrease Accelerometer (Vibration or external Shock
according to the demand. monitoring system) [15]. This sensor provides data
logging signal to the BlackBox Application running
B. Benefits of the open architecture controller
on PC Computer.
1)The use of the C + + programming in the design of the
control software. Software routines can configure and imple-
ment new functions to increase the machine tool performance.
2)The application possibility of algorithm development of
adaptable control for new applications, which uses force sen-
sor, vibration sensor, acoustic sensor, etc.
3) The algorithm execution of special servo-control,
increasing the machine tool precision.
4) The use of the same operator interface for different
machines, simplifying user’s training and reducing the costs.

III. SYSTEM COMPONENTS OF BLACKBOX OF MACHINE TOOL

A. Open Architecture Controller
A commercially available Open Architecture Controller
(OAC) purchased from SIEMENS [5] as the foundation of
our system. The selection of the SIEMENS control was based
on the following factors:
1) We wanted a Windows PC based controller that would Figure 1. BlackBox linked with peripherals via Simatic Net
both control the CNC and run this applications simultaneously
C. Software Components
with no adverse effects on the machining process.
2) The system must have the ability to obtain position A schematic of the software components is shown in Fig
information, i.e. x, y, z, sp1, sp2 etc in real time, along with 2.
other sensor information such as slide and spindle motor
power and slide velocities. It is critical that there be excellent
synchronization between program models and real time

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 Human Machine Interface (HMI advance with
PCU50.3)
 Programmable Logic Controller (S7-300 PLC)
 Numeric Control Kernel (840D/810D CNC)
 Drive control (SIMODRIVE devices, 611U drives)
 CPU – PCU50.3 or PCU50 with HMI Advance
software installed
B. Application Concept
This application monitor [18] Numeric Controller, Drive
control, Programmable Controller, Operator controls Panel
and Machine Control Panel as Clint Server Model for it
database in a cyclic manner illustrated in Fig 3 and Fig 4.

Figure 2. BlackBox linked with peripherals via Simatic Net
1)Operating System: Windows XP. It takes very few
percentage of the CPU capability of the PC to control the
CNC, leaving plenty of excess capability to run our
applications.
2)Open Architecture Control Software: SIEMENS
OpenCNC[16]. A key ingredient to this is the use of shared
memory where both the SIEMENS controller and our
application can simultaneously access vital information like
the current G-code line number, axes position, velocity and
spindle speed[17].
3)Real-Time Extension: The Windows operating system is
not specifically designed for real-time operation so it requires
some care in using it for CNC control. Reliability and safety
are paramount concerns. A real-time command structure is
Figure 3. BlackBox interact with different units of Machine Tool
required so that the motion control always receives the high-
est priority. The communication between applications and
NC/PLC is carried out via the OPC or Sinumerik-COM inter-
faces. Communication with NCK shows restricted real time
behavior.
4) Software Development Environment: Microsoft Visual
Basic and Visual C++ 6.0. All of our application software is
written in C++ providing speed, flexibility and portability.

IV. SYSTEM IMPLEMENTATION
A. Basic machine tool elements:
The functions of the CNC control are split up in five
components
1) Human Machine Interface (HMI)
2) Programmable Logic Controller (PLC)
3) Numeric Control Kernel (NCK)
4) Drive control (SIMODRIVE devices) Figure 4. Flow Chart of BlackBox Application
5) Communication between the areas and with external Alls these data’s will be stored into password protected Data
components Base at the time of Machine crash and can access only by
There are many players in these fields, mainly Siemens, Machine Tool Manufacturer via Web Page or Tele Service
Fanuc, Allen Bradley, Hitachi, Mitsubishi are the major once. illustrated in Fig 5.
In order to realize this unique concept we have used Siemens
Control System. Here are the few details.

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 Number of Tools, tool parameters, offsets and tool
magazine
 Spindle and Axis Overrides.
 Important NC and PLC data
 Events, Alarms and PLC messages.
 Status of all I/O’s of PLC, Geometrical position as
well as Rotational angle of all axis
 G, M parameters in use and operating mode AUTO/
MDI/JOG of Tool machine.
E. Application Results
BlackBox application source code developed around
Visual Basic and Microsoft Access to capture data from NC,
PLC and HMI controllers and write it on database file, as
shown in Fig. 7 and Fig. 8 respectively at the moment of
Figure 5. Remotely Retrieval of Black Box database machine crash.
This complete Application developed in VB [19] platform.
And its Data Management is build around Microsoft excess
[20]. Event of crash is very essential in this application. There-
fore, a dedicated sensor ‘Accelerometer’ is mounted on
spindle to trigger the event of crash to BlackBox via PLC as
shown in Fig 6.
C. Important Features.
 Scans and stores machine status after every 1-
second.
 Up to last 5 min Machine data can be recovered just
before breakdown
 Up to 10 crash data files can be recovered from
machine Figure 7. VB program
 Crash data can be recovered remotely via Internet/
Ethernet, no need to be present at the customer place.
 Machine Breakdown reason can be known remotely.
 File is password protected
 Each Machine data is time stamped.

Figure 8. Machine crashed data file

F. Scope of improvements and future work
Database file of crashed machine is to be read thoroughly
by the person to understand the cause of Machine
Breakdown. Therefore, error in reading file and interpolating
the cause of failure may be the bottom neck here and also the
whole process is very much time consuming. So, there is
Figure 6. Event on accelerometer initiate the data logging always a possibility to build another application that will
D. How to achieve? read and analyses the database file and suggest the possible
cause of failure and also simulate the cause of machine
By monitoring
breakdown.
 OPC key Pad, MCP, R parameters, Main and Sub
programs.
© 2012 ACEEE 9
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CONCLUSION [14] Miles, P., 1998, “Open architecture: forecasting the adoption
wave”, Robotics World, summer, p.23-29. Oshiro, O.T., 1998, “A
The use of open architecture CNC is considered of great parallel control architecture to ultra-precision machine tool” (in
importance since it is a promising technology that acts in the Portuguese), Ph.D. Thesis Escola de Engenharia de São Carlos,
area of industrial automation, allowing the integration of the Universidade de São Paulo, SP. Brazil.
equipment, a friendlier interface in the configuration, machine [15] Schmitz, T.L., (2003) “Chatter Recognition by a Statistical
tool Communication and modernization. This new black box Evaluation of the Synchronously Sampled Audio Signal,” Journal
application for Machine Tool Industry is successfully of Sound and Vibration, 262(3): 721-730.
intergraded and tested with Siemens Open architecture CNC. [16] http://www.automation.siemens.com/doconweb/.
[17] Jerard, R B. , Barry K. Fussell, Min Xu, Chad Schuyler,
Donald Esterling, “Development of a Testbed for Research on Smart
APPENDIX A Machine Tools, “, Proceedings of 2006 NSF DMII Grantees
OAC Open architecture control Conference, St. Louis, July 24-27, 2006
CVR Cockpit voice recorder [18] P Jaehun, S Birla, K G Shin, Z J Pasek, G Ulsoy,S Yansong
and Y Koren, “An open architecture testbed for real-time monitoring
FDR Aircraft’s flight data recorder
and control of machining processes”, Proceedings of the American
CSMU Crash-survivable memory unit Control Conference, pp 200-204, Seattle, USA, 1995.
SDM Sensing and diagnostic module [19] http://msdn.microsoft.com/en-us/vbasic/default.aspx
MPI Multipoint interface [20] http://office.microsoft.com/en-us/access/default.asp
OPC Operator panel control
MDI Machine data Input BIOGRAPHIES

REFERENCES Atul Gupta received the B.E. degree in
electronics and telecom engineering from
[1] OMAC (Open Modulate Architecture Controllers) http:// Army Institute of Technology, affiliated
www.omac.org/ to Pune University, MH, India, in 2002,
[2] OSACA (Open System Architecture For Controls Within and the M..Tech. degree in instrumenta-
Automation Systems), http://www.osaca.org/. tion from School Of Instrumentation, af-
[3] OPC, OLE for Process Control, (note that OLE stands for filiated to DAVV University, Indore, MP,
Object Linking and Embedding, http://www.opcfoundation.org/. India. From 2004 to 2007, he was with
[4] OSEC (Open System Environment for Controllers), the Research Division, TVS Electronics,
www.sml.co.jp/osec/. Bangalore, India, where he was working on development of On-
[5] http://www.automation.siemens.com/mc/mc-sol/en/9279dd53- Line uninterruptible power system, sine wave inverters, and low-
befd-4935-827a-11459b1a2863/index.aspx. power dc–dc converters. He also worked at Emerson Network
[6] D. Gee, The how’s and why’s of pc based control, IEEE 2001, Power as Champion R&D at head office at thane, India. Since Sept
pp. 67-74 2007, he has been with the Engineering Design Center, Carraro
[7] M Xiong-bo, H Zhen-yu, W Yong-zhang and F Hong-ya, Technologies, Pune, India, working on grid connected advance solar
“Development of a PC-Based Open Architecture Software-CNC inverter design. His research interest includes Industrial Automa-
System”, Chinese Journal of Aeronautics, Science Direct, vol 20, tion, Power Conditioning, Solar Energy, Hybrid Energy; Grid In-
pp 272-281, 2007. terconnection of Renewable Energy sources.
[8] http://science.howstuffworks.com/black-box.htm. Venu Uppuluri Srinivasa, holds Master’s
[9] Requirements of Open, Modular Architecture Controllers for degree in Mechanical from Osmania Uni-
Applications in the Automotive Industry, Version 1.1, (1994), versity, Hyderabad, A.P, India. He also
Chrysler, Ford, GM. holds Master’s degree in management &
[10] http://www.motorists.org/edr/. Post graduate diploma in Financial Man-
[11] Koren, Y., Pasek, Z.J., Ulsoy A.G. and Wright, P.K., 1996b, agement discipline. Has over 20 years of
“Timing and Performance of Open Architecture Controllers”, experience as an IT / ITes Technologist
Proceedings of the ASME Dynamics Systems and Control Division with both established public companies
ASME, DSC-Vol.58. and Venture funded startups. Held senior
[12] Schofield, S., 1996, “Open Architecture Controller for executive roles in product marketing, strategy, product develop-
Advanced Machine Tools”, Ph.D. Thesis, University of California, ment and business development. Currently working as General
Berkeley. Apud Wright P. et. al., 1996, “Open architecture control Manager and Head for Carraro Technologies India Limited (an Ital-
for machine tools”, Integrated Manufacturing Laboratory, ian Company) since 6 years representing Board as an authorized
University of California, Berkeley, Nov. signatory. Also signed as board of director for Santerno India Pri-
[13] Pritschow, G., Daniel, C.H., Junchans, G. and Sperling, W., vate Limited. Served in the capacity of Engineering Director for
1993, “Open System Controllers – A Challenge for the Future of Emerson Electric Co. (USA), Group Manager for Tecumseh Prod-
the Machine Tool Industry”, apud, Altintas, Y., and Munasinghe, ucts India Limited
W.K., 1994, “A Hierarchical Open-Architecture CNC System for
Machine Tools”, CIRP, Jan, Vol.43.

© 2011 ACEEE 10
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Black Box for Machine Tools; Based on Open CNC Architecture Control Systems

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Black Box for Machine Tools; Based on Open CNC Architecture Control Systems