Power Supply Converter

[Jannie]

We replaced a C-Touch with the new model and on the newer system the power supply connector is now a 7-pin vs the older 4-pin.

Clipsal is shipping a 4-pin to 7-pin converter to make this all work (they never shipped a replacement power supply with the new touch screen) but we need to get it working urgently.

Does anyone have the pin-outs for this converter? I've already got the plugs, so we can easily make it up.

Failing that, can anyone help with what voltage should be on what pins on the new, 7-pin connector? Have not been able to find it on-line and the local Clipsal guys don't know.

Any urgent response will be really helpful. :o

[ashleigh]

You MUST MUST MUST use the converter. It has protection and other circuits in it.

[Jannie]

Thanks, if Clipsal actually could get their logistics sorted out, we would need to resort to trying to cover for them. Seems their Xmas lunches are more important than customers. :rolleyes:

One thing that came out in this forum around the power to the C-Touch is its apparent sensitivity to voltage fluctuations, for example the sensitivity to the length of the DC cable.

This greatly worries me as in any real-world situation these can be expected to some degree. Yet it seems the unit is sensitive to variations of as little as hundreds of millivolts?

What are the voltage input specs on the unit? Typical industrial PC's will work over quite a wide range of input voltage, typically 5 to 18 volts.

What is the spec for this unit?

[ashleigh]

Original model units had a fixed length cable attached to the power supply. If you didn't fiddle the cable, there were no problems of voltage. If you cut the cable and shortened it, you could put in too many volts and damage the unit.

The new model + power supply uses a compensator / converter to make sure that the right voltage goes into the unit, and the cable length can be varied.

The issue is not "how sensitive is the unit to voltage change", because thats all handled by the power supply (original model) or the power supply/converter-adaptor (new model). The issue is "how do you do a design thats robust over user conditions without dumping loads of heat from a regulator", and thats that hard part that the adaptor/converter handles in the new model.

[Jannie]

Original model units had a fixed length cable attached to the power supply. If you didn't fiddle the cable, there were no problems of voltage. If you cut the cable and shortened it, you could put in too many volts and damage the unit.

The new model + power supply uses a compensator / converter to make sure that the right voltage goes into the unit, and the cable length can be varied.

The issue is not "how sensitive is the unit to voltage change", because thats all handled by the power supply (original model) or the power supply/converter-adaptor (new model). The issue is "how do you do a design thats robust over user conditions without dumping loads of heat from a regulator", and thats that hard part that the adaptor/converter handles in the new model.

To be honest this is just very poor design. If you need a fixed voltage at the PC, irrespective of the load, you run a high-impedance sense wire back to the PSU that can then control the PSU voltage output.

If making the cable shorter can increase the voltage so much that it can damage the PC, it points to a very poorly designed PSU and/or a DC cable with high resistance in the first place. And a PC without any input protection. Both of these are not acceptable.

It's quite worrisome that Clipsal will put products into the field that are so sensitive to voltage fluctuations or heat issues.

On this point, why did you bring up the heat issue, something else we need to be aware of?

To answer your question: "how do you do a design thats robust over user conditions without dumping loads of heat from a regulator", the answer is pretty simple:

Engineers have been designing stable and robust computing platforms for many, many years, it's not rocket-science anymore. Touch Screens have been used in very hostile environments for a long time.

Maybe the real question is if the platform Clipsal chosen was the right one in the first place? PC's are notoriously unreliable and often a liability in any Automation environment.

[Jannie]

Eventually measured the pin-outs on the new Touch Screen and made our own cable, so it's all working now.

[Conformist]

Eventually measured the pin-outs on the new Touch Screen and made our own cable, so it's all working now.


For how long???? Not a very smart move if you ask me, given the adapters are provided free of charge and that Ashleigh has highlighted the dangers

[ashleigh]

Your opinions about competence or otherwise are your own.

Your modification will not be covered by any warranty.