Dear sir,

Could anybody help me to overcome this problem.
We are using a pc monitor to see the process status of our machine. So far we had 3 burnt out monitors. Now we use to off the monitor and when we want to see anything than only we will switch on the monitor. Sometimes the screen will shrink day by day and the end, monitor out. Could anyone can help me with this, Do we need to install any kind of surge protector for the power line or any kind of protection for the data cable which enters it.

Thanks in advance,

Ravi, FP Technologies

 

Hello Ravi,

I have had an experience like that once. We had a Servo Amp connected to a 120VAC supply (secondary) of a transformer that also supplied power to a plc, pc, and monitor. All three died eventually. At that time, we decided to install a second transformer for clean power to the sensitive items...

I was not involved in the original design... Just the fix up.

Anyways, here's what happened. When the disconnect was removed or the e-stop was hit while the servo was doing some hard accelerating, it was drawing near max current from the transformer. But when the transformer no longer had any energy in it, the servo robbed energy from other devices connected to the secondary of the transformer.

I don't think a surge suppressor will fix your
problem, since the voltage is actually lower...
It is the current that killed everything. So that
is why the "isolation" transformer was installed
to fix the problem.

The drive should have had a filter on the input side too...

Oh, I forgot to mention to fuse supply side of the sensitive devices...

Dan Boudreault

 

Maby you could use a TFT Flat screen. Im not sure of this but i beleve that you will get one of those to last longer. But it sound strange that you have burnt them out. We have many process monitoring computers out there, constantly on and with no screensavers. A modern monitor should simpy not burn out. On the rare occations when a monitor has quit working it has either been very old or there has been some strong magnetic fields where the monitor is placed. Most often from high power electrical wires nearby. Im not sure of this either but I guess that a TFT monitor is less sensitive to magnetic fields.
Good luck

Fredrik Hogberg
KomfortAutomatik AB
Sundsvall
Sweden

 

Try an LCD monitor.

 

Make sure your Monitor AND the PC share the exact same power socket/strip. Keep in mind the signal between the PC and the display is simple "IC" level signals & assume a shared ground. If you run the PC through a UPS and the display direct to AC, then your display data cable may become a
lower-impedance ground path for the PC. Even powering them from 2 different feeds in your power system may cause undesired ground current to flow between them.

Since you've had problems, I'd literally force them to share the same power socket (like 2 plugs of the same duplex outlet) and I'd also manually
connect a frame ground wire between the two chassis. It is a very cheap, easy way to eliminate this possibility.

Best Regards

Lynn August Linse, Senior Product Application Engineer
15353 Barranca Parkway, Lantronix Inc, Irvine CA 92618
[email protected] www.lantronix.com
Tel: (949)450-7272 Fax: (949)453-7132

 

Fredrik Hogberg is right, you shold use a TFT display. A 15.1" TFT has a viewing area equivalent to about a 17" CRT and should last significantly longer is you an industrial version.

There are at least three problems with CRTs which make them undesirable for Industrial purposes:

1. The burn in problem which ANY CRT based monitor will have. Yes they're better, screensavers and power control will help, but in time they will still burn in.

2. They are very susceptible to stray magnetic fields. I saw some monitors in a chemical factory once, wrapped in mu-metal jackets and the display still bouncing like a rubber ball. I think sea sickness pills must've been provided for the operators.

3. The power supply intolerance. Unlike a solid state display which usually has a switch mode PSU that'll often take 85-240V input, CRTs like stable A.C. mains with no interferance.

Of course I would say all this, we sell industrial flat panel monitors. But the market for industrial CRTs is in rapid decine and sales of TFT based monitors is doubling each year. That's customer choice for you.

Tony Lane
Proface UK
http://www.reja.btinternet.com

 

HI
I have two CRT-based PC monitors(one-PHILIPS 15B 15",other nonamed 14") in SCADA applications (SAAB TRL/2-OPI and SIMATIC S5-AB ControlView).
Both works good about five years aprox.24 hours/day

About your problem I think next:

-install PC monitor via UPS (17" CRT-based
monitor need aprox.120VA power).
-UPS unit can protect with PWS socket adapter
named Surge Protective Device-Overvoltage
Protection Adapter, as maked by
manufacturer DEHN Germany, S-Protector
Article No.909 821 for European voltage,with:
nominal disch.cnt 3kA
maximal disch.cnt 5kA
voltage prot.level 1.5kV
response time <30nsec

or equivalent for 115V-US standard.

Monitor signal cable isn't problem.

Regards
Z. Vlah