M
When this topic started, there was a brief discussion on what "open control" might look like, but it seemed to have petered out. I thought though to outline some ideas I've had as to what a control system based on "somewhat open" principles would mean for the structure of the automation components business.
I will use a hypothetical case to illustrate the points. Assume the application is a small, fully automated assembly machine. I would speculate that a system would look something like what I have listed below. Virtually everything I have listed already exists to some extent. It would however become the norm, rather than the exception.
- The I/O is separated from the PLC CPU. This assumes that *all* I/O is connected by some form of "fieldbus" or I/O network. The I/O market would be dominated by a few specialist companies selling commodity I/O. Competition would be based to a large extent on price for the most common types.
- Smaller I/O companies would exist to fill niche markets.
- The number of different "fieldbuses" or I/O networks would decline, as the less common varieties die out. If people are buying their I/O and CPUs separately, they will want the I/O network which is most widely available.
- Most PLC CPUs would be integrated into some form of MMI panel (likely a touch screen system). Many systems already use separate PLCs and MMI panels. If the I/O isn't directly connected to the CPU anymore, then there is no reason to put the CPU inside the control panel. This means the MMI panel and PLC markets would converge.
- "Soft logic" systems would predominate. It does not necessarily follow that this means "PC based control" though. It just means that the CPU (logic solving) hardware and software could be separated if the buyer wished. Alternate soft logic systems could be installed.
- Special soft logic systems would be directed at particular markets. There would even be standard packages available for particular common applications. Real time concerns could be addressed with real time operating systems.
- Price competition in the CPU market would mean that companies selling low end CPUs would have to look very hard at licensing costs for third party operating systems. This would mean either no operating system, or a cheap (or free) one. This would be transparent to the customer if the soft logic system is sold pre-installed in the CPU hardware.
- I/O would be more distributed than it is now and mounted directly in the machine. For pneumatically actuated devices, I/O nodes would consist of a valve node containing a single valve with sensor inputs integrated into it. E.g., a cylinder which requires a valve and two MRS switches would plug the hoses and wires into a single I/O node block. Larger cylinders could have this node block integrated into them (e.g., plug directly into the end cap). Manifolds may no longer exist except when dealing with large numbers of very small cylinders.
This means the pneumatic companies may dominate much of the I/O market since they would make the valve/sensor modules.
- Terminal blocks will largely disappear since the traditional I/O wiring will no longer exist. They will still be needed for power distribution, but the the overall terminal block market would be much smaller.
- Instrumentation will connect to the CPU via an I/O network or "fieldbus" instead of an analogue signal. Most of the existing market for intelligent signal conditions (e.g., ones with built in displays, limits, alarms, etc.) would disappear as this functionality is incorporated into the PLC software. The exception would be for the more sophisticated systems that need direct access to the instrument I/O (e.g., press force monitoring systems).
- With the PLC, I/O and most of the terminal blocks gone from the control panel, all that would be left in many cases is the disconnect and lock-out, power supplies, fusing, and the safety controller (which implements the safety interlocks). This means there may be a market for pre-assembled panels in standard sizes. You would order it according to desired voltage input and power supply size. You would install your own safety controller and make the external connections.
- Servo or stepper drives would co-operate with PLCs more closely. The higher level motion control programs could run in the PLC CPU along side the regular soft logic system (integrated together somehow), with just the lower level control logic running in the drive.
What is needed to make the above work is mainly a standard, open, universal I/O network. Everything else already exists in some form. The difference is more a matter of degree of emphasis rather than any new technology.
What I have suggested as being different though is how the business is split up. Traditional PLC manufacturers may not have the I/O market. The soft logic systems may be separated from the hardware. However, I suspect that most people will want to buy the latter two (soft logic and CPU) as a package.
Getting into the PLC business would be much easier though since a company wouldn't have to provide a range of I/O. They could just either private label third party I/O, or simply suggest that their customers buy the I/O from whomever they wish.
I think the above business implications are realistic. Does anyone have any comments?
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Michael Griffin
London, Ont. Canada
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I will use a hypothetical case to illustrate the points. Assume the application is a small, fully automated assembly machine. I would speculate that a system would look something like what I have listed below. Virtually everything I have listed already exists to some extent. It would however become the norm, rather than the exception.
- The I/O is separated from the PLC CPU. This assumes that *all* I/O is connected by some form of "fieldbus" or I/O network. The I/O market would be dominated by a few specialist companies selling commodity I/O. Competition would be based to a large extent on price for the most common types.
- Smaller I/O companies would exist to fill niche markets.
- The number of different "fieldbuses" or I/O networks would decline, as the less common varieties die out. If people are buying their I/O and CPUs separately, they will want the I/O network which is most widely available.
- Most PLC CPUs would be integrated into some form of MMI panel (likely a touch screen system). Many systems already use separate PLCs and MMI panels. If the I/O isn't directly connected to the CPU anymore, then there is no reason to put the CPU inside the control panel. This means the MMI panel and PLC markets would converge.
- "Soft logic" systems would predominate. It does not necessarily follow that this means "PC based control" though. It just means that the CPU (logic solving) hardware and software could be separated if the buyer wished. Alternate soft logic systems could be installed.
- Special soft logic systems would be directed at particular markets. There would even be standard packages available for particular common applications. Real time concerns could be addressed with real time operating systems.
- Price competition in the CPU market would mean that companies selling low end CPUs would have to look very hard at licensing costs for third party operating systems. This would mean either no operating system, or a cheap (or free) one. This would be transparent to the customer if the soft logic system is sold pre-installed in the CPU hardware.
- I/O would be more distributed than it is now and mounted directly in the machine. For pneumatically actuated devices, I/O nodes would consist of a valve node containing a single valve with sensor inputs integrated into it. E.g., a cylinder which requires a valve and two MRS switches would plug the hoses and wires into a single I/O node block. Larger cylinders could have this node block integrated into them (e.g., plug directly into the end cap). Manifolds may no longer exist except when dealing with large numbers of very small cylinders.
This means the pneumatic companies may dominate much of the I/O market since they would make the valve/sensor modules.
- Terminal blocks will largely disappear since the traditional I/O wiring will no longer exist. They will still be needed for power distribution, but the the overall terminal block market would be much smaller.
- Instrumentation will connect to the CPU via an I/O network or "fieldbus" instead of an analogue signal. Most of the existing market for intelligent signal conditions (e.g., ones with built in displays, limits, alarms, etc.) would disappear as this functionality is incorporated into the PLC software. The exception would be for the more sophisticated systems that need direct access to the instrument I/O (e.g., press force monitoring systems).
- With the PLC, I/O and most of the terminal blocks gone from the control panel, all that would be left in many cases is the disconnect and lock-out, power supplies, fusing, and the safety controller (which implements the safety interlocks). This means there may be a market for pre-assembled panels in standard sizes. You would order it according to desired voltage input and power supply size. You would install your own safety controller and make the external connections.
- Servo or stepper drives would co-operate with PLCs more closely. The higher level motion control programs could run in the PLC CPU along side the regular soft logic system (integrated together somehow), with just the lower level control logic running in the drive.
What is needed to make the above work is mainly a standard, open, universal I/O network. Everything else already exists in some form. The difference is more a matter of degree of emphasis rather than any new technology.
What I have suggested as being different though is how the business is split up. Traditional PLC manufacturers may not have the I/O market. The soft logic systems may be separated from the hardware. However, I suspect that most people will want to buy the latter two (soft logic and CPU) as a package.
Getting into the PLC business would be much easier though since a company wouldn't have to provide a range of I/O. They could just either private label third party I/O, or simply suggest that their customers buy the I/O from whomever they wish.
I think the above business implications are realistic. Does anyone have any comments?
--
************************
Michael Griffin
London, Ont. Canada
************************