Teardown: Fluke 725

[somlioy]

Thought I'd do a teardown of the Fluke 725 multifunction process calibrator
I'm not an expert taking photos so bear with me. Also I didnt notice there were something on the lens before I was done, and I couldnt be arsed to take new photos. 

Pictures are clickable for larger photos.















This connector is mainly for pressure calibration, but it also works as an serial port for computers.
Unfortantly I don't have either of these devices. Maybe someone knows the pinout and what protocol it's using?












50mA/250V rated fuses.






The springy connector is for the thermocouple,

[SeanB]

Love that thermocouple input with the huge copper cold junction with the thermal sensor right next to them.

Would love to have one of these!

[sotos]

I went for one of these, when I heard the price, I fell down and they called the ambulance.

[SeanB]

You do get change when you buy them, but only if you went in with enough $100 bills to fill a airline baggage bin. Then you need the same again for the accessories, like leads, batteries, pressure sensors ( oh, you will need 4 bins of those hundreds though for the pressure sensor if you want anything above the basic).

Bring in a few gold bricks, it will be easier to carry. 40kg will just about cover the full suite.............

[somlioy]

Luckily my company paid for it.

The protocol it uses on the top connector is RS232, atleast that's what it say when I enable it. Just need to figure out the pinout...
The connector on the top is Lemo branded. Apparantly high quality, swiss-made.

[somlioy]

Alright, I've figured it out. RS232 communication. Talking to the meter with hyper terminal, putty or w/e.
Commands at page 23:
http://www.tequipment.net/pdf/Fluke/72x_CalibrationManual.pdf

[Bored@Work]

I was curious about the Martel Electronics silk screen. Fluke bought the company last year,and before cooperated with them for 15 years.

[SeanB]

As these are a slow mover it is likely a board that was made a few years ago and placed in storage until needed. Most of the chips are datecoded 2006, so likely it was a batch made in 2007 and placed in sealed storage until needed, with possibly some parts not placed until options were decided.

[somlioy]

Correct, this unit was bought in 2006 or 2007 iirc.

[sotos]

Why they don’t lower the price and hit the market, rather having them sit there from 2006.

[SeanB]

Of the hundreds of members here how many do process control and calibration? Small market, and a really long life unit, so very small sales. It is a signal source mostly to calibrate. 30V, 4-20mA and thermocouples, along with process controls and checking pressure transducers. If they sell 50 a year it will be a big amount.

[rsjsouza]

somlioy, thanks for sharing these nice pictures!

[chrome]

Of the hundreds of members here how many do process control and calibration? Small market, and a really long life unit, so very small sales. It is a signal source mostly to calibrate. 30V, 4-20mA and thermocouples, along with process controls and checking pressure transducers. If they sell 50 a year it will be a big amount.

Well this is aimed at industrial use (note the 4-20mA signal) We use these at work to control valve while tuning the 0 and 100% points but also to check stuff like temperature sensors and so forth, I will bet you they sell a lot more than 5000 per year.

[tsmith35]

Just noticed that the Martel MC-1210 appears to have all the functionality of the Fluke 726 (and more), but at a much lower price. Interesting...

http://www.martelcalibrators.com/mc-1210_calibrator.html

[radioorizont]

Hi,
Just saw your post and i was looking to access the calibration menu in a 725ex as your photo suggested.
The unit does enter calibration and relevant info shown on it's screen.
The 725ex has the same port and seems like it sends data the same way, but regardless of the bitrate (default 9600 with correct parity etc. as mentioned in service manual) i get gibberish in Putty.
Did you have to put a resistor on any of the rx tx lines or any other modification?
I tested baud rates from 100 to 100k+ and no readable information.
Thanks,

[Arhigos]

Hi,
Just saw your post and i was looking to access the calibration menu in a 725ex as your photo suggested.
The unit does enter calibration and relevant info shown on it's screen.
The 725ex has the same port and seems like it sends data the same way, but regardless of the bitrate (default 9600 with correct parity etc. as mentioned in service manual) i get gibberish in Putty.
Did you have to put a resistor on any of the rx tx lines or any other modification?
I tested baud rates from 100 to 100k+ and no readable information.
Thanks,

725ex should work same way as 725 regular. Make sure that you don't have pressure measurement active when unit connected to putty

[Smith]

These things are nice to work with, I use the 726 quite often. It only has a few drawbacks (besides the price). The batteries drain so fast, specially in current source mode, and the output banana connectors aren't spaced the normal 19mm apart (I really hate dislike that).
There is a Fluke 189 battery holder that will fit this device, and it holds 4 C cell instead of 4 AA cell batteries. As a bonus, it makes the device stand on it's own quite steady as it's quite big and heavy when put together.

Link: https://www.fluke.com/en/product/accessories/batteries/fluke-bp189