Agilent U1242B IR Interface ?

[sradtke]

Hallo,

I have a question regarding the U1242B digital multimeter. In all the documentation there is no mentioning of an ir interface.
But when I looked at the back of the housing I couldn't help noticing the two 'eyes'. And when I opened it, there are two leds
on distance pieces. And as you can see in the second picture the pcb is fully populated.
So what's the story here? Is there a way to get this interface to work?

Stephen




     U1242B Back



     U1242B PCB

[gobblegobble]

Nice serial number you got!

I'd hazard a guess that the U1240 and U1250 series share the pcb and the logging features and the like are disabled on the firmware... but the meters differ enough to say it's not so (probe jack locations moved etc).

It may be intended for service use only, but it'd be silly to make a optically isolated connection for just that...

[mikeselectricstuff]

It may be intended for service use only, but it'd be silly to make a optically isolated connection for just that...

Not necessarily - for automatic factory test & calibration, a few cents on an IR pair, especially if also used on other models, would make  lot of sense and easily pay for itself.

[firewalker]

Are those Ir leds for sure? Is around there any chip for serial communication e.t.c.?

[mikeselectricstuff]

Is around there any chip for serial communication e.t.c.?

Wouldn't need one - you can do IR comms with a LED and phototransistor on a couple of MCU pins and a couple of resistors.

[sradtke]

Nice serial number you got!

I'd hazard a guess that the U1240 and U1250 series share the pcb and the logging features and the like are disabled on the firmware...
but the meters differ enough to say it's not so (probe jack locations moved etc).

Sorry gobblegobble, I have to disappoint you. The serial is shopped ( also the bar code  if some of you try to get my serial number ).

And also on your second remark you are wrong. They might use the same pcb since the jacks are on an extra little pcb
srewed to the main pcb. And on the main pcb there is no device name ( U124xx ) printed on it.

Stephen

[saturation]

It should be easy to test by sending it data, but is there such an option on the menus for the 1242b?

[sradtke]

It should be easy to test by sending it data, but is there such an option on the menus for the 1242b?

No, I checked. I was hoping for a special key sequence to enable this feature if it is there - somewhere.

Stephen

[Mechatrommer]

last time i saw/read a DMM hack to enable the communication (serial iirc) by shorting ic's pin, i forgot and not sure where it was. google might help.

[kek]

I get a one shot set of IR pulses when I choose a different setting with the selector switch on mine.

Ken

[alexwhittemore]

My guess is that they're for firmware updating. I know at least for the 125Xa/b series, firmware updates are easy-peasy through the USB IR cable and don't require user interaction on the meter side. I'm definitely speaking out of my ass right now, but from my experience, my guess is that the meter tries to handshake over IR on startup. If it detects a cable present, it's open to receive a firmware update from the PC. I'd be willing to bet that if you hold the USB IR cable for other meters up to it on startup, you could initiate a firmware update with the right software. But of course, I don't see any download on the interwebs for it, so it's probably a factory-service-only thing.

[Swift]

It's surely possible, because last year Agilent introduced U1177A, IR to Bluetooth adapter. It connects to the IR port and allow you to remotely acquire data on your android device, similar functionality to Fluke 233. And 124*b is listed as compatible. There is surely no mistake, because there is U1179A, IR Connectivity Bracket For U1240 exists.

I get a one shot set of IR pulses when I choose a different setting with the selector switch on mine.

Ken

Yeah, I also see it.

Unfortunately I do not have IR to USB adapter to sniff difference between U1240 and IR-enabled dmm.

So it's certainly software restrictions, rather caused by IR adapter or PC drivers. It looks pretty Agilent-like to restrict some functionality by software (like memory and digital channels in oscilloscopes or even much more expensive options).

[PetrosA]

The U1242B can be used just like any of the other Agilent DMMs with IR for either the USB cable or the U1177A Bluetooth adapter, but you need a U1179A adapter:

http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&nid=-536902461.1006716&pageMode=OV

I mentioned this in my recent video, but I guess not everyone got the memo