Author Topic: VC8145 thread ... It's here, finally (Read 104786 times)

nctnico · « **Reply #75 on:** December 27, 2012, 06:50:57 pm »

I've used a Canon camera not some cheap-ass camera from a mobile phone. The part number is really hard to read even using a 5x magnifier lamp. Actually the picture is more legible than when using the magnifier lamp! The AD737 makes sense. The quality of the part number stamp is really poor.

rsjsouza · « **Reply #76 on:** December 27, 2012, 07:27:07 pm »

I see then... The part markings may be etched (they are very hard to read unless lighting hits them at a specific angle). Thanks anyways.

T4P · « **Reply #77 on:** January 20, 2013, 11:08:02 pm »

Finally had time to do a teardown/review. I wrote all night for this one

http://the4thpin.comeze.com/2013/01/21/vc8145-review-finally-about-time-i-guess/

alm · « **Reply #78 on:** January 21, 2013, 12:11:43 am »

RS-232 is isolated, but the transformer only has one secondary winding as far as I see. How is the PC side of the opto-coupler powered? Is there a TTL to RS-232 level converter after the opto-coupler? If these are powered by the handshaking lines, you might run into trouble with some USB-RS232 converters. I know Fluke made an RS-232 to IR cable which only worked with a limited set of USB-RS232 converters. I wonder if their 'special adapter' has something to do with this.

The ground pins of the RS-232 connector should be connected to earth ground, curious that they chose to omit any ground connection.

4 readings/sec for the digits and 40 readings/sec is pretty much standard for any decent handheld DMM I've handled. The '30 year old tech' bench meters will do much more, especially in 4.5 digit mode.

nctnico · « **Reply #79 on:** January 21, 2013, 01:29:30 am »

I just did some testing and I could use the PC control software by connecting a standard RS232 cable to the back of the VC8145. So it seems the optocouplers are getting powered by the computer's RS232 interface. I have used similar tricks in my own designs when RS232 was common.

T4P · « **Reply #80 on:** January 21, 2013, 04:10:16 am »

Quote from: alm on January 21, 2013, 12:11:43 am

4 readings/sec for the digits and 40 readings/sec is pretty much standard for any decent handheld DMM I've handled. The '30 year old tech' bench meters will do much more, especially in 4.5 digit mode.

Yeah when they have like nominal 5.5d mode. Please. I can't get any of those meters for under 300$ (If shipping from US, it's a bomb) if i wanted to. PLEASE!
"Decent handheld DMM" In context i am speaking of 150$ brand new DMMs with 80000 count resolution. Not that you can find any.
MS8218? 2 rdgs/sec
UT71D? 2 rdgs/sec

Quote from: nctnico on January 21, 2013, 01:29:30 am

I just did some testing and I could use the PC control software by connecting a standard RS232 cable to the back of the VC8145. So it seems the optocouplers are getting powered by the computer's RS232 interface. I have used similar tricks in my own designs when RS232 was common.

In the same way the UT61E's RS232 works i guess

Wartex · « **Reply #81 on:** January 21, 2013, 04:17:08 am »

Quote from: EEVblog on December 19, 2012, 05:09:52 am

Guys, stop the slanging match now, or the thread gets locked.

Dave.

Slanging means having a huge dick. You mean "slandering", perhaps?

elcomtel · « **Reply #82 on:** July 20, 2013, 12:14:35 am »

For what this bench multimeter is intended for I think this is a fine meter. As far as the criticism regarding the free space inside, Aka 'lunchbox'.

This cavernous space opens ups some possibilities for custom expansion. Think of the possibilities and what you could use that space for. There are lots of kits on the market that are expected to be used in conjunction with a multimeter. Now you have the perfect multimeter that you can easily modify.

SeanB · « **Reply #83 on:** July 20, 2013, 04:51:54 am »

Best use of the space is to remove the mains transformer and replace it with a 16VAC 1A unit with an interwinding shield, and put in a 4AH SLA battery and charger in there. That way you have a power supply that is both mains and transportable. Connect the mains ground to the RS232 shell and the screen winding on the transformer to it. Add in a mains common mode filter with an earth choke and some transient suppression as well, so as to reduce conducted noise from interfering with your high resolution measurements.

Otherwise you could put in a small microcontroller board with a SD card slot ( Rasberry Pi)and have a nice datalogger with a very large sample memory and the ability to do long term logging. woul probably need a battery as well and so use a 2AH SLA instead and build a switching 8V regulator for the multimeter itself to reduce power drawn from the battery when mains fails.

Uwe Hermann · « **Reply #84 on:** July 23, 2013, 10:57:58 am »

Just some additional info: The review page at http://the4thpin.comeze.com/archives/1260 says "Fortune FSuP01-003, couldn’t find that on the web ANYWHERE".

The company is Fortune Semiconductor, http://www.ic-fortune.com/. Can't find a datasheet for the specific chip atm, but the FS970X datasheet at least mentions it under "typical application circuit" and shows the pinout.

http://www.ic-fortune.com/upload/Download/FS970X-DS-42_EN.pdf

Uwe.

silicon junkie · « **Reply #85 on:** November 21, 2013, 06:10:18 pm »

Anyone had any luck getting the RS232 to work on the VC8145 multimeter?
I have the opto-coupler powered & wired correctly but just don't get any data out.
I have also tried sticking a scope directly on the PCB where it drives the opto-coupler and can't see any data at all
(Yes i have enabled the RS232 by pressing the 'timer' button for two seconds)
Thanks

nctnico · « **Reply #86 on:** November 21, 2013, 09:14:16 pm »

I managed to get it working. AFAIK you must NOT press the timer button; RS232 is on by default.

gljoshhunsaker · « **Reply #87 on:** March 10, 2014, 06:25:30 am »

Hi,

I wanted to put another post in on this topic (I don't see many other threads online that have any info about this piece). I picked one of these guys up and have been very impressed so far. My cheap Innova 3320 handheld meter was not able to do a current draw measurement of any kind on a particular product sample that I have been testing, but the VC8145 worked a treat. Provided what appeared to be very reliable (in terms of matching what was stated from my company's manufacturer) current draw measurements so far. The backlit display is lovely. The quaint little built in function generator option is kind of cool! (I still need to verify it against my rubidium standard calibrated frequency counter, but neat regardless).

I have noticed the mA readings don't zero when nothing is hooked up (floats between about +2 - 4 microamps), does anyone know of a way to internally calibrate this unit for that kind of thing? Not a huge deal, but otherwise this is pretty decent really.

lupine · « **Reply #88 on:** April 20, 2014, 07:32:59 pm »

SB, thanks I like that Idea I was actually thinking the bigger LiPo battery in side and a"PiTop" that connects to this meter for power and to the data port of the meter with appropriate sized screen and room for connectors for using a BitScopeMicro as a sort of sub $400 all one mobile digital test lab...any thoughts ... in the meantime the 20A fuse will keep me from blowing it up on slot car projects (7.5 - 16VDC & 3 to 16 amps) and the 36 hour logging ability will allow me to track the power usage for my current battery powered projects (semi portable clock radio's that only need 24 or so hrs of UPS) without cranking up a computer... unless I find better bang for the buck this is the one I'm gonna order one when the paycheck comes around. more l8r

Quote from: SeanB on July 20, 2013, 04:51:54 am

Best use of the space is to remove the mains transformer and replace it with a 16VAC 1A unit with an interwinding shield, and put in a 4AH SLA battery and charger in there. That way you have a power supply that is both mains and transportable. Connect the mains ground to the RS232 shell and the screen winding on the transformer to it. Add in a mains common mode filter with an earth choke and some transient suppression as well, so as to reduce conducted noise from interfering with your high resolution measurements.

Otherwise you could put in a small microcontroller board with a SD card slot ( Rasberry Pi)and have a nice datalogger with a very large sample memory and the ability to do long term logging. woul probably need a battery as well and so use a 2AH SLA instead and build a switching 8V regulator for the multimeter itself to reduce power drawn from the battery when mains fails.

Hydrawerk · « **Reply #89 on:** September 03, 2014, 10:15:40 pm »

Quote from: T4P on January 20, 2013, 11:08:02 pm

Finally had time to do a teardown/review. I wrote all night for this one
http://the4thpin.comeze.com/2013/01/21/vc8145-review-finally-about-time-i-guess/

That link does not work anymore.

mstck · « **Reply #90 on:** September 04, 2014, 05:03:52 pm »

I just received one of these and I am now getting to know it. I have a question about the default start up. The unit I have starts with RS232 enabled and auto power off (APO) disabled. To turn on APO I have to press the Timer/RS232 button. Is this the default position others observe?

nctnico · « **Reply #91 on:** September 04, 2014, 08:57:39 pm »

Why would you want auto power off? The transformer uses more energy due to losses than the rest of the meter.

Macbeth · « **Reply #92 on:** September 04, 2014, 09:11:43 pm »

Quote from: nctnico on September 04, 2014, 08:57:39 pm

Why would you want auto power off? The transformer uses more energy due to losses than the rest of the meter.

I've always hated APO even on my battery powered meters. Why subject yourself to that shit when you have a bench meter, even if it is a bit of a joke meter?
(The least hey could have done with all that wasted space was have a little cabinet to keep all your probes and sensors in?? - I could go along with that)

nctnico · « **Reply #93 on:** September 04, 2014, 09:15:17 pm »

A bench meter usually is 99% empty space. My HP3466A is the same. It's a bit weird to comment on a box being empty because there is more or less a minimum volume requirement for a bench meter

Macbeth · « **Reply #94 on:** September 05, 2014, 02:17:37 am »

Quote from: nctnico on September 04, 2014, 09:15:17 pm

A bench meter usually is 99% empty space. My HP3466A is the same. It's a bit weird to comment on a box being empty because there is more or less a minimum volume requirement for a bench meter

Not at all - all the latest DSO's are compact and bijou. Why can't bench meters, specifically ones that don't have anything in them, not follow the same form?

Your HP3466 has a large circuit board and no doubt cooling requirements. The same can't be said for the VC8145. It loses all credibility.

nctnico · « **Reply #95 on:** September 05, 2014, 09:35:37 am »

No, the HP3466 is just as compact (no cooling requirements) and empty as a VC8145. The reason for the minimum volume requirement is that bench equipment typically gets stacked. So if they all have the about the same size you can make a neat stack. I have 2 VC8145 and a bench power supply stacked on top of eachother. Before that the HP3466 was in that stack. If the VC8145 was much smaller it could not be stacked and would clutter the desk space.

Wytnucls · « **Reply #96 on:** September 05, 2014, 09:56:59 am »

I don't think you could make the HP3466 much smaller, unlike the VC8145:

nctnico · « **Reply #97 on:** September 05, 2014, 12:56:10 pm »

Still there is plenty of empty space in the HP3466 if you look from the side. They could have made it a lot smaller but they didn't because the designers could fill the entire box if they wanted. I see a lot of green on the circuit board which means a lot of board space is not used / the components are spread widely over the board. They could have cut the height in half easely.

Again: a bench multimeter is supposed to have a certain size and the VC8145 fullfils that requirement. By making it smaller it would be useless as a bench multimeter because you can't stack them properly. If you want a small multimeter you have to buy a portable one; the VC8145 is not for you.

k2teknik · « **Reply #98 on:** November 03, 2014, 01:33:18 pm »

Quote from: silicon junkie on November 21, 2013, 06:10:18 pm

Anyone had any luck getting the RS232 to work on the VC8145 multimeter?

Yes with the sw that is on the cd supplied with the instrument, I think it is a tow-way protocol so one may have to start talking correctly to the thing to make RS232 work.
There is a bug in the sw,you have to set you PC not to use comma as decimal point otherwise you will get a lot of errors.
The sw is most likely made for an other instrument and I am missing a useful guide for this.

Do any know about the sw protocol for this instrument?

MarkPalmer · « **Reply #99 on:** November 03, 2014, 05:48:51 pm »

You could always secure a lead ingot in that empty space in the VC8145 to keep the little fella from sliding around

Beckman bench meters from the 80's were sort of the same way- except you could load D batteries in the empty space to make them portable.

HP bench meters of the past, like other HP test gear, went in to a system of standardized case sizes called, "Clement cases." Whichever one fit the circuitry and overall design the best is the one that got used, so sometimes there was some internal space unaccounted for. But with this system they didn't have to come up with a new case for every single instrument.

-Mark-


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Author Topic: VC8145 thread ... It's here, finally (Read 104786 times)

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