Monitoring serial communication/reverse engineering a protocol

Hi,
Unless you have a digital storage oscilloscope or a serial data analyser and know how to use 'em.
OR
You have good manuals for the products at either end of the wire, the patience and wit to slog through them both and understand them.
Then I'm afraid you have a very difficult task with little chance of success..

My best advise in that case is to get some help from someone familiar with the devices... maybe try their tech' support or web sites...or if you buy enough product maybe a tech' rep'?

Good luck

Del

Good luck

Del

If I understand correctly, you have an inclinometer, which came with a cable for connection to a PC serial port, and some software to run on the PC. Am I right so far?

If this is the case, you should be able to get the comms protocol information from the supplier (or manufacturer). I can't see any reason why they'd not release that kind of data. Maybe there's a technical manual that they don't usually distribute (because most users don't need it).

BTW -did you get it (new) recently, or have you 'inherited' it (one way or another)?

If it's old kit, you're probably back to Del's take on it. Tricky!

I agree with what Del and John have said. You may find that if you google the brand and model number you'll find someone who is using that model who knows its ins and outs.

Sometimes the command to get a device to do something or return data is in plain English. I used to fool with laser disc players, and some would play given some code like B2 or 2&@[[, but others would play given PLAY (imagine that!). So if all else fails, you could use a terminal program and just type anything that seems likely and see if you receive data back. If you were lucky, I suppose you might find it simply sends data in a stream once it receives a "clear to send".

You mention software. Does it communicate with the device? If so, then your job may be easier, because you could set up a laptop to emulate the device, and see what the software sends to the device.

Dear Sir,

First of all if you require data monitoring only without any control output then any data logger ( RECORDER) will fulfill you purpose in that case the out put from your inclinometer ( 4-20 mA or Volt) should be connected to data logger which will monitor the data & simultaneously the DATA LOGGER should have RS232 or ethernet comm. port from where it can be connected to PC for real time data monitoring .

IN case you have PLC with SCADA for data monitoring & controlling then O/P from inclinometer should be connected to PLC i/p module .PLC should again have the communication port to connect it with PC where you can monitor the data with SCADA software.

REgards

Rakesh Bhat

Hi,

Thanks for all the answers! Well, I haven't mailed the manufacturer yet, but I'm about to do that now. It is a 'FAS-G' combined gyroscope and inclinometer from microstrain (www.microstrain.com), and I bought it new. I was just wondering if there was an alternarnative way to obtain the information needed, in case MicroStrain are not willing to give out any information.

If all else fails, there are "sniffer" programs out there (I don't remember the last one I used, but I do remember it was open-source) that can be used to monitor a communications link to determine what is going on (generally requiring a second computer and a hack of a connector to give taps to the #2 & #3 pins). You can see what is sent and what is received. Then you have to translate this in to something you can understand...You probably also need to monitor the other control pins as well. I have encountered MANY companies that consider such information proprietary, Del.

Hi again,

I contacted MicroStrain and they sent me the documentation. Thanks for all your help, though :)

- Eirik

A program to communicate through RS232, on your computer is Hyper-Terminal. It is amazing (see what Del mentioned) that Microsoft allows you to use it, without paying royalties!

You may try the Hayes code for modems (AT, +++. etc) it could work for commands. Google for Hayes AT command set.