FeelTech FY3224S 24MHz 2-Channel DDS AW Function Signal Generator

[ledtester]

...
What about the software port of the MHS-5200 to the FeelTech FY3224S?
http://hackaday.com/2015/07/01/hacking-a-100-signal-generator/

It would be really nice to have this software available for the FY3224S as it is apparently compatible with the arbitrary waveform format of the easy to use Waveform Manager Plus software!
http://tti1.co.uk/downloads/waveman-plus.htm
...

Well, the github code referenced to in the hackaday article is simply a spreadsheet and some awk/shell scripts, and combined with the information in reply #19 of this thread it should be rather easy to modify to use Feeltech's serial protocol.

The Waveform Manager Plus program apparently is a Windows-only executable.

I think it would be worthwhile to develop a browser-based program to control these function gens. From what I understand, you can perform serial I/O from the major browsers now, so the program should be rather straight forward to write.

[ruiseixas]

Hi,

I can't find the CD-ROM of this device (FY32000S) and there isn't any page with the driver and software. I found this http://www.feeltech.net but I can't read chinese 

Can some one give me a link?

Thanks

[Texacate]

Who is going to contact FeelTech about the power issue?
...
Who is going to port the software program of the MHS-5200 to the FeelTech FY3224S?

At the price point of this FG (mine was $69.99 including shipping on bangood.com), I highly doubt FeelTech is likely to address either issue.  No where do they claim the product is safety certified by any US or european safety standards lab.  This is surprising honest, as plenty Chinese products are stamped with false or intentionally misleading CE/UL logos when said-equipent would never meet said-safetly-standard if actually tested. 

I just don't see a motivation to compete in the "sub-$100, safety certified, function generator market".  This stuff is targeted towards one-man shops in the Pac-Rim countries, and hobbyists in the US and Europe.   Real electronics laboratories will buy real Siglent, Rigol, Agilent, BK-Precision, branded, safety certified FGs, and pay well over $400 for them.

I'm not trying to discourage anyone from raising up the issue to the manufacturer, but speaking for me... I stand a better chance of being shocked that FeelTech responded to our INVESTIGATION of ghost voltage on the BNC connectors,  than being LITTERALLY shocked by an ACTUAL FAULT in the function generator power supply AC coupling caps.

Just for fun I might go test some other stuff I have in my house with two-conductor power cords looking for AC ghost voltages...  I wonder what my Blu-Ray player does...

[Texacate]

A Sony DVD player showed 53v on the ground side of the RCA jacks (and the metal chassis) relative to earth ground measured with my Brymen-257 multimeter on the standard AC setting.  This voltage is independent of the DVD player being On or Off.  However, when using the LowZ  setting on my multimeter the voltage drops  to ~1V.  The FY3224S measures the same. 

I'm not convinced this ghost voltage is even a safety issue, rather a natural side affect of how switching power supplies are designed…  Still… I FEEL better leaving the switch I installed in the setting that connects the FG's DC ground to mains-earth ground.  I'll leave it in that position unless I have a reason not to.

Cheers.

[Aruck]

I just modded my FY3224S with a proper 3-wire grounded power cord... and managed to blow up the power supply board, (in spectacular fashion I might add), in the process of making this thing "safer".    I won't go too deep into my faux-pas, but suffice it to say that you are supposed to connect the SECONDARY-side-gound (low voltage gound) to mains-earth-ground.  Do NOT, under any circumstances, connect the PRIMARY-side "ground" of the switching power supply to mains-earth-ground.   That isn't a meant to be earth-ground.  It's the ground "reference" of the primary.

I've noticed that FeelTech is using whatever power supply they can get their hands on, as mine looked nothing like the ones posted by med6753 & tombddiver.  My unit came with a very nice SICO-650 power supply.  (Well, it WAS nice 'till I fried it).  I put in a "Universal DVD Replacement Power Supply" I managed to find on Amazon. It took some searching to find one with the required +5v & +/-12v  outputs.

My mod included a toggle switch in the grounding path, in case I ever have the need to "float" the BNC outputs, the way the unit is shipped from FeelTech.  Otherwise that switch stays in the safe/gounded position.

One more note;  The sticker on the bottom of the unit is printed on an ink-jet printer.  If it gets wet, it will bleed and smear.

Back when I was in school I too attempted to ground the DC outputs of a full bridge rectifier. Consider it a right of passage

I received the same power supply that you did.

[LogicalDave]

Who is going to contact FeelTech about the power issue?
See in the thread above for contact details of the company FeelTech.

I don't have all the details of the power issue at hand, and believe it would be better if the OP of the power issue takes the initiative.

I just sent an email to Carl at Feeltech (their sales manager for foreign business) describing the problem and asking them to suggest a fix.  At present, a 2-pin polarized AC replacement connector or 3-pin AC connector with DC ground connected to earth/safety-ground seems like the best solution.  It would be nice if they could identify a connector that fits the case without modification.

[Aruck]

A standard 3 prong plug will require mods to the case.

[Kalvin]

Would an ordinary 50/60 Hz mains transformer with linear regulators solve the leakage problem as transformer circuits typically do not use Y-capacitors? For the 5V rail an simple buck-converter might be a nice solution if the heat should be a problem. The pictures show that the enclosure is almost empty, so there should be plenty of room for a small mains transformer and linear regulators + 5V buck converter.

[med6753]

A standard 3 prong plug will require mods to the case.

That is true. I drilled a hole in the case. Inserted the 3 wire cord. Knotted it for strain relief. Dodgy but effective.

[med6753]

Would an ordinary 50/60 Hz mains transformer with linear regulators solve the leakage problem as transformer circuits typically do not use Y-capacitors? For the 5V rail an simple buck-converter might be a nice solution if the heat should be a problem. The pictures show that the enclosure is almost empty, so there should be plenty of room for a small mains transformer and linear regulators + 5V buck converter.

It is a possible solution and has been discussed. Check out some prior entries.

[Texacate]

An IEC320-C6 power inlet jack (like this one with the mounting flanges) will fit with just a tiny bit of cutting to make room for the third wire. It's the exact same width as the two-conductor jack I removed from the FY3324S.  Some sellers call them "power entry jacks".

http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4

I personally used an IEC320-C14 jack (in a similar style with the mounting wings). That one took quite a bit of cutting.   I kinda wish had waited, but the C14 arrived at my doorstep first, and I was impatient to mod my function generator. The C14 is overkill for something that draws less than 100mA of AC current.

[milamber]

For those who are unsure wether to ground their function gen or not:
In this thread you can see that a lot of higher priced function generator like Rigol DG1032z do not have floating, but earth grounded outputs:
https://www.eevblog.com/forum/testgear/function-gens-with-floating-outputs/.

This of course does not help you, if you acutally need floating outputs and bought the device for such a purpose.

[FlyingHacker]

My old IEC F34 actually has a little thumbscrew screw that you can tighten to connect the earth ground, or loosen to make it floating. I guess you can just as easily insert a three prong to two prong adapter when you wanted make it floating (for this FeelTech). Note never float your scope...

[alsetalokin4017]

My old IEC F34 actually has a little thumbscrew screw that you can tighten to connect the earth ground, or loosen to make it floating. I guess you can just as easily insert a three prong to two prong adapter when you wanted make it floating (for this FeelTech). Note never float your scope...

Ah, the Indestructible Interstate, also sold under the Racal-Dana brand. 

I have an IEC F43 "High Voltage" FG, and it has a slide switch on the back panel that selects Signal Ground to be Isolated (floating) or Chassis (grounded). All the BNC connectors are isolated from the chassis ground, unless this switch is in the "grounded" position. On mine I installed a front panel switch in parallel to this factory switch since I can't easily reach around to the the back of my instrument stack.

Somehow I thought that the F34 also had this back-panel switch, but I can't seem to find my F34 to check.

[FlyingHacker]

Yeah, I love my F34. It was my first function gen, and I fixed it up myself...

I has a thumbscrew, rather than a switch.

[GigaJoe]

added 3wire power socket, but, instead short connection of central ground power wire and the device ground I use a 2.2mf 250V capacitor (110V wall power) voltage drop to 0.1V , did I made it right ?

still some noise at range 10-20 mV in the output signal, some 10-20 MHz

[GigaJoe]

Spectrum 1K , output 6V indicated on device, equal 0db input for sound card, recorded by Xonar, -120db. FFT max resolution 8M.
(green, white - both channels, but they equal )

THD calculated up to 15 harmonics: 0.131424857 %

0.15% i would say ...

[LogicalDave]

I'm not convinced this ghost voltage is even a safety issue, rather a natural side affect of how switching power supplies are designed…  Still… I FEEL better leaving the switch I installed in the setting that connects the FG's DC ground to mains-earth ground.  I'll leave it in that position unless I have a reason not to.

I'm not convinced it's a safety issue either although having looked at the internals, I'd be completely shocked (no pun intended) if the design meets safety standards (UL, CE, etc.).  Assuming the EMC cap that bridges the HV and SELV sides is a Y1 rated capacitor and suitably sized (smaller than ~1-5nF iirc), and ignoring other questionable mains safety issues, then IEC950 requirements for class II (unearthed) power supplies limit maximum leakage (touch current) to 0.25mA (much lower than the 4-6mA GFCI trip level).  I measured mine and with the power on it has 32uA of touch current and with power off it is 110vac at 50uA; in either case, it's well below the 250uA limit.

However, even if it is not a safety hazard, this is *definitely* not what I want from test equipment that I will be connecting to sensitive electronic equipment whose ground may be earth referenced.  The DC outputs of all of my other test gear float with respect to AC mains or are earth grounded.  Fortunately, the fix is straightforward.

So far, the manufacturer has not responded to my inquiries.

[LogicalDave]

An IEC320-C6 power inlet jack (like this one with the mounting flanges) will fit with just a tiny bit of cutting to make room for the third wire. It's the exact same width as the two-conductor jack I removed from the FY3324S.  Some sellers call them "power entry jacks".

http://www.amazon.com/Black-IEC320-Inlet-Power-Socket/dp/B008X0WET4

Thanks Texacate, I've ordered the same jack from Amazon (for $5.74 w/free shipping); the same jack is available on eBay a little cheaper ($3.42 w/free shipping) with a little slower shipping: http://www.ebay.com/itm/Black-3-Pin-IEC320-C6-Inlet-Plug-Power-Socket-AC-250V-2-5A-/311080812333

[pa3hfu]

Hi All!

A few days ago I received my FY3224s. What a little beauty 

For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.

Nevertheless, for $60 it's a nice generator!

[JoeO]

Hi All!

A few days ago I received my FY3224s. What a little beauty 

For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.

Nevertheless, for $60 it's a nice generator!

What is wrapped up in the silver duct tape?

[pa3hfu]

Hi All!

A few days ago I received my FY3224s. What a little beauty 

For safety I placed a 3-pole power inlet and made it switchable (isolated / chassis) on the back side.
The same for the (sometimes annoying) beeper.

Nevertheless, for $60 it's a nice generator!

What is wrapped up in the silver duct tape?

500 gr. lead 

[GigaJoe]

question: to use a capacitor inline a ground wire, instead  direct connection, is it correct ? or better to use a switch ?

[Texacate]

question: to use a capacitor inline a ground wire, instead  direct connection, is it correct ? or better to use a switch ?

I have no idea.  I wonder how high-end function generators (with floating output options) are designed?   It's cool this thing has so much room inside for all these hacks/upgrades/customizations.   

[pa3hfu]

I find the rotary knob has a lot of 'backslash'. Is that a common "feature"?
It seems to be not very simple to replace.