LCP WITH TOUCH SCREEN

What does the Contol and OPerational Philsophy States / What does the PID shows , Local Control Symbol Will be different

Moreever Just check area classification if ur Changing Push Button to TP 270

Regards

Jose John

Notone8,

"Right or wrong" is a relative question. Your process must ensure safety for the people present. Emergency stops or other similar controls must either use PLC's or similar computer-type devices that are specifically designed for such use, or must be wired with separate maintained-contact push-buttons and relays. Beyond that, my next concern would be with the possibility of the system receiving conflicting inputs from two or more LCD touch screens at the same time. I hope your programming would be able to prevent this from occurring, such as by having a ranking of which control locations over-ride others or which logged-on operators can over-ride others.

Your question lacks a lot of detail about the type of process or environment you are working with, but that is understandable for many reasons. Touch-screen LCD controllers are available from many sources. Some of them (such as those from Horner, but others are available also) integrate the inputs/outputs, the screen logic, the process logic, and the communications all into a single unit that can be networked with others. I believe such units could do what you describe, depending on limits of the number of screen images needed to describe the whole process and the amount of inputs/outputs needed. Fiber-optic communication is possible with these. The methods you would use to do the logic and communication could create a system that is very tolerant of failures in any one node (such as notifying other nodes when one has failed or even to having another node take-over the portion of logic and control that the failed node was handling.

An intriguing and "avant-guard" approach, if you ask me. Just pay attention to the cautions I mentioned above.

--JMM

are your questions related to the design of no buttons or the technical aspect of it?

Well there should be at least one button the LCD on/off button.

cannot have that on the touch screen (well off is ok ) but On?

apart from all the above inputs,

I hope you would be having the user acess levels, also from which touchscreen or screen did the command come. or from which screen was the alarm acknowledge, these are important in troubleshooting some times. Also with so many screens and all screens accesible from all screens, it will be difficult if two people accesing the same page one trying to shut of a valve and other open it,

I do not understand why you would require any person from anywhere acess any part of the plant. If such an access is required then why not setup a control room have 4 screens where you could monitor and control the plant in first place, rather than having 30 Local displays, where any body from anywhere could tamper anything without Hinderence .

My only advice is to make sure you get a robust touch screen. Having operated equipment with touch screen I can tell you if they get used a lot, you will find yourself replacing them often.

That being said I would put repetitive functions on hard wired buttons and use the touch screen for the lesser used functions.