We have some PCs here at work that are connected to production
machinery and used to "automate" the control of the unit.
These PCs have flat panel TOUCH screens as monitors so the operator
can just point at what command option he wants.
One of the panels has failed and we need a couple of new ones.
I was asked for advice on what 15" flat panel TOUCH screen to buy.
Lord only knows why they asked me..... but they did.
Anyone have advice on what touch screens to get? And price IS a
http://www.elotouch.com/ is the OEM for many machine builder's touch panels.
They are available as either CRT or LCD and can pe purchased with full NEMA
4 sealing for an industrial enviornment. A 15" TFT LCD XGA Nema 4 with
serial touch will run around $1500.
There are (very) basically two different types of touch screens (with a
number of variations) which, one could say, are analogous to digital and
The "digital" type is actually a matrix screen with rows of conductors
on one layer and columns of conductors on the other. Where you touch a
row and column together corresponds to a specific signal. That is to
say if you had a touch screen with 9 columns and 9 rows you could
possibly have up to 81 different signals. The on-screen menu "buttons"
have to be programmed to correspond to the correct intersection of rows
and columns, so that limits what you can do with the screen.
The "analog" type actually translates a level of resistance (i.e.,
voltage gain) to a position on the screen. And of course that means
that programming is easier.
You've got quite a little reverse-engineering job here, because you
either have to match a "digital" (row/column) screen with the same
widths/heights and number, or match an "analog" with the exact same
resistance/voltage gain touch screen, plus (for either type) you have to
match the signal on the connector(s) and have the same type of
connector. If the touch screen is a matrix ("digital") screen you can
probably tell it my looking at it carefully with a magnifier. There
will be slight gaps in the rows/columns. A touch screen manufacturer
should be able to reverse engineer the unit for you, but don't expect to
get away cheaply. Custom screens are expensive. If the screen is
"analog" you've really got a problem because you can't ask a touch
screen manufacturer to match the gains in a non-functional unit. If you
have a FUNCTIONAL unit on another machine the you'll probably have to
send THAT off to a manufacturer (and pay through the nose as with the
matrix screen). Your best bet is to contact the OEM of the PCs, even if
you don't like them. Their "high" prices will still be lower than what
you'll pay to match the screen from a different manufacturer.
Mark 'Sporky' Stapleton
WaterMark Design, LLC
There is at least a third type. Honeywell touch screens have an array of
LEDs and receivers across the bottom and top of the screen as well as on the
right and left. It senses where in the x-y world a beam is broken. When
you withdraw your finger the action is triggered. Absolutely no pressure is
required. You should be able to recognize if yours is of this type because
the touch feature is a frame around the screen and electronically totally
separate from it. It can be added to any type of screen or even to a
painting on a wall!
A fourth type works on capacitance. Modicon used to use these but I am not
familiar with them.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.