ENET RS485, multidrop network using addressed sensors, how to identify data ?. Sample program needed

[Ebele_Obijiofor]

Hello,

There is no standard protocol for addressing devices on a multi-drop network. Usually, you send the address first, and then the command, terminated by a carriage return or linefeed, depending on the instrument. This is just an example, and your instruments might be different. You did not mention what instruments you have, but you could probably find out what what protocol they use from the vendor. Hope this is helpful. Thanks!

Regards,

[Hec]

My network has Senix ultrasound sensors. The command to poll data is S + address (for example S01). Now my application challenge is to make a Labview program to synchonize reading of many sensors and be able to pick up clear data of each one. In my first trial (having only two sensors in the network) once a request data to one sensor and then to the other, I collecting a big mess. The network has the command (S01 or S02), right data like 02033, mix S0235x&9, wRS24, 55555555555555..., could be any thing.

Obviously I have to filter what I am reading from the network once I request data from a particular sensor, then I have to clear something to avoid accumulation of previous reading.

I hope this replay is more clear of what I need.

Thanks

Hector

[Robert M]

Hi Hector,

Unfortunately we do not have any examples available that address what you are doing.  There is a KnowledgeBase on our site entitled Addressing Different Devices in RS-485 that may be of some help. 

Your network seems to be setup correctly since you are able to communicate. 

The user manual for your Senix sensors should detail the format for sending commands and well as what you should expect to receive back from them.  What are you expecting to receive compared to what you are receiving? 

A utility called NI-Spy may be of some use to you.  There's a tutorial for it called Performing a Good NI-Spy Capture for Debugging/Troubleshooting.  This utility will show you what driver level calls you are making as well as what is being returned.

Hope this helps,

[gjels]

Hi Hac,

Did you find a solution? I am working on a problem like yours but I have a problem getting my instrumet to sent data back when I sent a command like "M0xx" M=get data, 0=instrument ID.

If you found a solution I would be happy if you would tell me a bout it

kind regards

gjels