Trotec EC060V - Shutter does not operate

[Fraser]

A sample rotary solenoid datasheet is attached. These things are more current hungry than I expected ! Almost 400mA in the case of the attached example.

[Fraser]

This rotary solenoid is nearer to your units resistance and needs around 315mA to operate. It is a bi-stable model but I would expect the coil currents to be similar.

[Martin72]

These things are more current hungry than I expected !

Therefore a current limitating resistor above say 10 ohm wouldn´t make sense.
But the circuit must deliver the current for only a short time ( how long ?).
Tomorrow I´ll test the solenoid with a little bit more power...

[Fraser]

Useful page on the rotary solenoids used in thermal cameras etc

https://www.brandstrominstruments.com/standard-rotary-solenoids.php

[Martin72]

Interesting!

Hmm...which type the cam got...
I guess none of the three as the shutter will be forced back due to the spring.

[Fraser]

The attached CAD file suggests that your coil resistance would be designed for 3V to 5V direct operation (no current limiting resistor).

[Martin72]

So "tomorrow" I´ll set the current limit up to 700mA and the voltage to 3V, then we´ll see if something´s happen.
If it works, next step will follow, checking the signals via scope.

BTW:
Why is this needed ?
I mean the shutter, why you must cover the "sensor" for a short time ?

[Martin72]

Shutter/solenoid works!
Giving more current and it reacts on/off wise.
So the failure must be on the pcb...Time to do some reverse things.

Martin

[Bill W]

BTW:
Why is this needed ?
I mean the shutter, why you must cover the "sensor" for a short time ?

Microbolometers are chronically unstable with ambient / sensor temperature.  So, about once a minute there is this process (#) written into the software:

Close shutter
Look at data
Work out what to add / subract from the pixel data to get a flat image of 'all pixels are the shutter temperature'
Save differences for each pixel
Open shutter
Add/subtract pixel differences from every frame from now on.

(#)
There are 'shutterless' cameras that try to remove the patterns by image analysis and more comprehensive calibration vs sensor temperature.

Bill

[Fraser]

I have tried to identify the IC marked “330h” but came up empty. I thought it could be a logic driven mosfet switch or even just a MOSFET pair but have not found a likely identity

For certain you can treat it like a “block”…… power and 0V input, control input on/off (likely whatever voltage the processor generates at its I/O and a output drive to the load(FFC solenoid). It will be a case of checking for the presence of reasonable voltages on that IC’s pins and seeing whether it is getting the correct inputs and producing the expected output as a result. Hopefully reverse engineering that small circuit will be relatively easy. That hand soldered connector is worth checking for continuity as well.

Fraser

[Martin72]

Hi,

With a very high possibility I´ve found the suitable one...
So next step is to solder a testlead onto pin 5 (on/off) for checking it with scope.
Martin

[Martin72]

It´s getting more and more interesting...
First, it´s indeed a FDC6330L switch (U10), pinout matches with the results I´ve get with scope.
Second...
No need to solder a testlead, the tip of the scope probe is small enough - But the cam must be disassembled, I couldn´t use its battery, so I connect a PSU adjusted to 7.2V and appx 750mA on it.
Surprise:
After pressing on, PSU reaches the limit...Hm? OK, more current...
Pressing start and two things happen.
Initial input current is above 1A  And: First time ever I´ve heard the internal beeper while starting...
After this, current decreases to "stable" 520mA - Boy, didn´t expect so much.
Then measuring and yes, it´s like fraser wrote, the input signal is 1sec width and got an amplitude of 3.3V .
And this will periodicly happen every minute....
Watching the current meter on the psu, when input pulse appear, current rises over 800mA...Hm...
Measuring the output to the solenoid....aha, output is given !!!
What´s going on here...And I don´t know what I´ve done, I´ve moved the spring letting the shutter one time "flipsing" manually - After this, shutter is always active for 1 sec every minute until I´ve stopped the measuring.... or that was pure coincidence - Then I got a strange feeling gentlemen.
The Accu which comes with the trotec was claimed as "new" from the (private) vendor.
Looking at his specs...1000mAh...
I´m not a expert what accus concerns but could it be that this is simply too weak...??
Remember, I´ve heard the beeper sound for the very first time as the external PSU was connected.
Must think about it, here some pics..

[Fraser]

Some info that may help…

1. The start up current of the camera is high because the microbolometer incorporates a heater to raise the microbolometer die to operating temperature at thermal equilibrium. This is usually around 32 Celsius.

2. These cameras are not the best and I found my SATIR version microbolometer temperature stability during the first 10 minutes of use to be pretty poor. The FFC shutter was operated a lot as the camera stabilised. An FFC every minute sounds a bit too often but could be typical for this camera. Many cameras use a FFC interval of 2 Minutes or employ an active monitoring system to determine when an FFC is needed.

3. 520mA is not exceptionally high for such a thermal camera.I forget how long a battery is supposed to last in this camera but that could give you an idea of the expected current draw by the manufacturer. 1000mAh / Current draw = Maximum Run Time

4. The battery in my unit has died so I cannot do much with the camera at the moment. From memory the battery is available as a Sony camcorder equivalent. I forget the details though and would need to check. If the battery is not performing well, the run time will decrease but if the camera completes boot OK and runs for 10 minutes whilst stabilising, the battery is likely OK, at least in terms of system operation.

I will be sourcing a new battery for my camera and will share details if I identify which to buy.

Fraser

[Fraser]

Well that was easy 

The battery is a Sony NP-FA70 clone.

I attach a picture. My battery had a stated capacity of 1220mAh

Fraser

[Fraser]

A Germany based seller of a clone battery…

https://www.ebay.co.uk/itm/384964213398?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=t3HlhxGxQOO&sssrc=2349624&ssuid=BgpdXaaLSkK&var=&widget_ver=artemis&media=COPY

Cameron Sino batteries have been reliable in my experience.

Fraser

[Martin72]

Thank you Fraser,

Will buy it and then we´ll see what happen.
What do you think, is it possible that the shutter circuit won´t work correctly when the battery is too weak(not meant what steady current delivery concerns, meant in a "dynamical" way) ?

[Fraser]

The camera draws maximum current at first start so a weak battery would show up itself then. I would not expect the FFC flag to be a valid sign of a weak battery but then I do not know enough about this camera to be certain. Monitor the voltage across the battery with the camera starting and running. Look for a significant voltage drop on your oscilloscope when the FFC shutter should be operating. That will show whether the battery is suffering in a way that deprives the camera of adequate current availability.

I also have the identity of the expansion connector that attaches to the bottom of the camera if you think it would be of use to you. From memory, the camera takes serial UART and the docking station contains a UART to USB bridge pcb

Fraser

[Fraser]

The expansion connector plug is a Molex Handylink product that I bought from Radio Spares some years ago. It looks to be discontinued now.

The RS No. is 196-700

https://uk.rs-online.com/web/p/telecom-connectors/0196700

A cabled version was also available under part number 196-744

https://uk.rs-online.com/web/p/serial-cables/0196744

I likely have the pin-out somewhere as well but would need to find it.

Fraser

[Martin72]

Thank you again,
Would be interesting when I know the cam works stable.

A Germany based seller of a clone battery…

Have a look at the pic there and then on mine...
My accu "says" 7.4Wh, where the other is marked with 4.8
Hmm...

[Martin72]

Asked the seller, it´s 7.4Wh...
Ordered now, let´s see what will happen with a fresh new accu...

[Martin72]

let´s see what will happen with a fresh new accu...

Nothin new, re-assembling all together....Shutter don´t work.
It´s really annoying..
OK, tear it apart again...

[_Wim_]

Nothin new, re-assembling all together....Shutter don´t work.
It´s really annoying..
OK, tear it apart again...

Did you check those tantal elco's? Maybe the board has not enough capacity any longer to start the movement of the coil? You could try to add some temporary additional capacitance and power it from the battery to check if that changes anything.

[Martin72]

Hi....


Stupidly, the battery for my "new" thermal camera has not arrived yet, only next week....

This brought me to deal with the Trotec again.

Today I replaced the tantalum electrolytic capacitor(150µF...wow), which is directly connected to the shutter circuit.

Nothing...remains so, no shutter movement.

Nerve...What now.

So I investigated the board further.

The camera has a lot of switching supplies on the board, which convert the 7.2V of the battery, the "shutter circuit" also has its "own" supply, 3.3V.

I then soldered test leads directly to the exchanged tantalum and connected an oscilloscope to it.

I wanted to see if the voltage drops when trying to turn on the shutter.

So prepared the camera halfway assembled, the battery takes over the supply, switched on and....

....The voltage remains stable...

So it had nothing to do with the shutter being turned on when I connected an external power supply.

This must have had another reason.

This makes me so curious that I will measure again tomorrow, at various points.

More on this later.

[Martin72]

Hmm...
Scope is connected to output to the shutter, a second channel measures the current through the shutter.
Output is there, current is flowing also - but no shutter movement.
Interesting, must look further.

[Martin72]

Hi,

No caps, nothing on the pcb - It must be the "motor" of the shutter...
I took the camera apart and fed a 3.2V signal to the shutter "motor" whose connector.
Then turned on the power supply, a current flows, but nothing moves.
In the off state then moved with the finger the wheel on the motor, no tangible resistance, the mechanics with the shutter moves smoothly.
And now it comes:
Again voltage applied, the shutter moves...
Over and over again, as soon as the 3.2V is applied.
Then I let it rest for a few minutes, applied voltage again - Again only current, no movement...
This can only be the motor of the shutter, right?