English => Interfaces, Pinouts, Cables => Topic started by: CoralReef on Apr 07, 2010, 20:38

Title: Medical Grade Monitors and Regular Computer Monitors...
Post by: CoralReef on Apr 07, 2010, 20:38
I am not a video guy or a techie..I am a veterinarian. But, I do have a video problem. I am trying to use a standard flat screen ( LCD ) monitor on a medical anesthesia monitor, Datex Ohmeda AS/3

..( ) .

The problem is one of video compatibility. These monitors were made in the early 90's and are bullet proof. They never fail and that is why people want to use them.
A "medical grade" LCD can be used on the AS/3 but a standard computer monitor will not display. I tried a Dell monitor that gave the error " cannot display this video mode" and a gateway the displayed "out of range". From what I have been told this is not a resolution problem but one of scan or video type. The Datex AS/3 has a D-sub video connection

..( )

with 9 wires connected.

..( )

I believe this would be an VGA or early XGA output but perhaps not.

I tried connecting the CRT monitor that comes with the AS/3 to a computer but got an image that seems to reflect an incompatible scan.

..( )

My problem: What is the likely video out-put of this old device and do suitable converters exist to allow the use of a modern computer LCD screen?

The AS/3's monitor is of 1984 x 512 display resolution. Can this be a problem and can that be corrected?
Title: Re: Medical Grade Monitors and Regular Computer Monitors...
Post by: pablo1422 on Apr 14, 2010, 22:32
Your problem is that the "medical grade" monitor has a much different line frequency than a regular monitor. That's because a much higher resolution is required, and the LCD monitors that you have tried doesn't support it.

You may find an adapter, but if you can make it work the video quality won't be good.

My advise is that you get in touch with the manufacturer of your equipment and ask them if they have a suitable replacement monitor or adapter.
Title: Re: Medical Grade Monitors and Regular Computer Monitors...
Post by: AlexV on Apr 21, 2010, 02:51
Sounds like a simple refresh rate problem. On CRT, to avoid flickering and interference with 50Hz fluorescent light you want your refresh rate higher - like in the range of 100Hz+. The LCD is very different, your picture is not written to the display "on the fly" - it goes to the intermediate memory and from there with different refresh rate to the screen. So the refresh rate on LCD panel would always be different to the refresh rate being sent from the computer or AS/3 in your case. See wikipedia for "VGA" for more technical details.

So what you need is an expensive LCD monitor which supports high refresh rate VGA input.

To confirm this theory, try any decent old CRT monitor with your AS/3 - it should work.
Title: Re: Medical Grade Monitors and Regular Computer Monitors...
Post by: pbrunnen on Apr 27, 2010, 19:53
Well, I don't know about your particular unit... but I work with medical monitors.  Because of calibration reasons, hospitals often refresh their medical monitors every three to four years.  You might have some luck checking with area hospitals or even radiology groups.  You might be able to pick up an older monitor cheap.   Ebay would also be a good place to look.  I highly recommend the Eizo brand.

Hope that helps.
-Cheers, Peter.