S110 - Cannot drive by lab power supply? - page 2 - General Discussion and Assistance - CHDK Forum

S110 - Cannot drive by lab power supply?

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Re: S110 - Cannot drive by lab power supply?
« Reply #10 on: 28 / April / 2015, 12:58:47 »
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A crowbar circuit is an electrical circuit used to prevent an over voltage condition of a power supply unit from damaging the circuits attached to the power supply. It operates by putting a short circuit or low resistance path across the voltage output (Vo), much as if one dropped a tool of the same name across the output terminals of the power supply.

If your power supply works with other equipment, look at why the power supply fails with the camera.

External switched mode regulator loads activate the protection circuits of regulated power supplies.

Confirm by loading your power supply with a purely resistive load.

That will confirm the power supply is working correctly.


Re: S110 - Cannot drive by lab power supply?
« Reply #11 on: 28 / April / 2015, 13:38:59 »
External switched mode regulator loads activate the protection circuits of regulated power supplies.
I put two capacitors (each 2200uF) parallel to the S110 - but this did not change anything :(
If I understand the issue of not running a switching mode regulator from another switching mode regulator,  then if those capacitors are big electrolytics then they won't help.  You really want to be using small ceramic type caps to bypass the high frequencies that may be interferring.

Note that most of the elcheapo Chinese camera power supplies are also switching mode regulators but they have presumably been designed to work with the regulators in the camera.
Ported :   A1200    SD940   G10    Powershot N    G16

Re: S110 - Cannot drive by lab power supply?
« Reply #12 on: 28 / April / 2015, 15:32:42 »
Hi,

So what type of capacitors I should use now? Which capacity?
I have an oscilloscope, can I measure something to find out what is going wrong?
2 x IXUS 860IS 100c
2 x Powershot S110 103a

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Re: S110 - Cannot drive by lab power supply?
« Reply #13 on: 28 / April / 2015, 19:05:38 »
I have an oscilloscope, can I measure something to find out what is going wrong?
You could try recording the camera's current draw and perhaps the power supply's output voltage if you have a digital scope. You can use a resistor (for example 0.1 .. 0.01 Ohm) in series with the camera to measure current.


Re: S110 - Cannot drive by lab power supply?
« Reply #14 on: 28 / April / 2015, 19:25:25 »
So what type of capacitors I should use now? Which capacity?
The correct answer will depend on a lot of things - especially the frequencies involved.  Off hand,  I'd suggest values between 0.1 uF and 10 uF  - ceramic or film types. 

A couple of ferrite beads on the individual power wires would not hurt either. 
Ported :   A1200    SD940   G10    Powershot N    G16

Re: S110 - Cannot drive by lab power supply?
« Reply #15 on: 29 / April / 2015, 02:23:51 »
So what type of capacitors I should use now? Which capacity?
The correct answer will depend on a lot of things - especially the frequencies involved.
A couple of ferrite beads on the individual power wires would not hurt either.
The Original Canon Battery Adaptors, that I have, just contain ferrite beads on the individual power wires
and nothing elce.

A few simple things to try:-

What Dose the Lab Power Supply Users Manual say about the "Protection" system used.

If it uses "Over Voltage" or "CrowBar" protection try a diode in series with the positve supply lead.
and also the with the filter capacitors sugested in the earlier posts.

Also you could try a old loud speaker from your junk component collection that is in parallel with a
low value series current measuring resistor (Reply #13 ), to simply listen to any audio frequency
circulating currents. A Peizo style speaker might also work when its also in parallel with the diode.

See this post for more detalis about battery "Internal Resistance" and camera current consumption.
http://chdk.setepontos.com/index.php?topic=12334.msg121845#msg121845
http://chdk.setepontos.com/index.php?action=dlattach;topic=12334.0;attach=11946

H-H

« Last Edit: 29 / April / 2015, 02:41:46 by Hardware_Hacker »

Re: S110 - Cannot drive by lab power supply?
« Reply #16 on: 29 / April / 2015, 13:36:20 »
May be better placed in a separate thread but seemed somewhat relevant here.

I'm considering a large cam count SX150IS rig. I'm not sure if 3.15V is critical but at around 6Watts/cam might anyone recommend a unit to supply a group of eight cameras (perhaps 16) ?

Oh, without breaking the bank into the bargian..!

Re: S110 - Cannot drive by lab power supply?
« Reply #17 on: 29 / April / 2015, 15:16:36 »
Hi,

I did a further test. I put the rechargeable battery and the lab power supply at the same time to my S110.
So both of them parallel to my S110. Then I switched on the cam without any problem. I could use the camera without any problems.
Then I took away the rechargeable battery - the power immediately goes down to 1.7 V again - current shows 0.00A. So no current was pulled. What does it mean now? Is my lab power supply defective?

 
2 x IXUS 860IS 100c
2 x Powershot S110 103a


Re: S110 - Cannot drive by lab power supply?
« Reply #18 on: 29 / April / 2015, 16:17:25 »
What does it mean now? Is my lab power supply defective?
Can you post a picture of your setup? 

What gage are the wires between your power supply and how long are they?

When you used an external 3-cell configuration did you attach it using the same wires your powersupply uses?
Ported :   A1200    SD940   G10    Powershot N    G16

Re: S110 - Cannot drive by lab power supply?
« Reply #19 on: 03 / May / 2015, 13:20:50 »
Hi,

finally I could continue to solve my problem.

@waterwingz: What gage are the wires between your power supply and how long are they?

These are typical wires for lab powersupplies, length 1m, diameter 4mm.
(something like this: https://www1.elfa.se/data1/wwwroot/assets/large/laborkabel-stift-4-mm-silikon-vergoldet-8.jpg)
These ones I used only to drive the cam by lab power supply.
But if you read further I used these cables also with my new power supply and there it works.

For comparision I bought a new lab power supply (Manson SSP-8160). And with this one I have no problems at all.
But I am still interested what was happening so I did some measurements with my oscilloscope (Hameg HMO1022).
I used my rechargable batteries (3x1.2V) and a shunt resistor (copper cable 0.5mm diameter, length ca. 34 cm --> 0.095 Ohms).
This shunt I put in series with my S110 and did a measurement of the voltage at the shunt in single-shot mode.
(screenshot see attached image).
On my oscilloscope I zoomed to the trigger point and found a peak of around 60mV. Together with my shunt resistor of 0.1 Ohm I get a current of 600mA. I doubt that my Voltcraft Digi40 could not handle 600mA.
May this several peaks the Voltcraft Digi40 could not handle?

What do you think?
2 x IXUS 860IS 100c
2 x Powershot S110 103a

 

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