Hi,
I want to recieve data from a bunch of devices mith an RS232 output. my problem is I dont have any idea how to connect more than one RS232 signal to the arduino and when I say a bunch I really meen it between 20 and 40 devices!
There is an alternative the devices have an RS484(I hope I remember the correct number) which should be able to tack them. gut I dont know the signal how its comming and how its formatted or anything so I'm probably stuck with a bunch off rs232 connections.
Extra serial pins can be achieved wit the software serial library.
http://arduiniana.org/libraries/newsoftserial/
However 20 to 40 devices is way beyond the capability of the arduino's software bandwidth.
You will have to use extra hardware UARTS:-
http://ics.nxp.com/products/bridges/uart.i2c.master.gpio/
But handling the data from all of those might be tricky if the through put is large. Exactly what are you trying to do?
Sounds to me...all you want is to access RS232 on a Computer, if such USB to Serial Severs or even Serial to Ethernet solutions will do for you. If not, what are you trying to do?
Do you control when the serial devices send data, like you send some data, the serial device responds ?
If not it's going to be very difficult, because if any of 20 - 40 devices can send data when they please, you will almost for sure end up in a situation where one device is sending data while you are servicing one of the other 39 devices.
If you have a call / response setup, you could use a bunch of analog multiplexors (cd4051 / cd 4067) to connect all your devices tx to Arduinos rx, and all your devices rx to Arduinos tx, and then with the multiplexor select one device at a time to communicate with.
But this will only work with call / response communication.
I want to get data from DC/AC Converters which are far away from home(like 200miles) prepare the data on the arduino and send it to my home server.
I couldn't find anything like a call/response system. it's probalbly each one sends it whenever it wants to.
Isnt there an atmel mikrocontroler(or any other ship) which can receive lots rs232 signals convert it into a new format(for all convertors) and send one to the arduino?
Edit: the traffic is pretty low like 50-80 characters per transmitted data set.(per converter)
far away from home(like 200miles)
How is that going to happen. Have you got 200 miles of cable?
It sounds like you haven't thought through your whole system. What you have described sounds like a non starter, but then you have no given very much information. For example
the traffic is pretty low like 50-80 characters per transmitted data set.(per converter)
Is totally irrelevant without saying how frequent the data set is sent.
I want to get data from DC/AC Converters which are far away from home(like 200miles) prepare the data on the arduino and send it to my home server.
Are the many converters all in one place? Can the data from all of them go through one forwarding device? Or does each need it's own forwarder? Or are the converters in groups? If so, how many converters per forwarder?
The Data from one converter via rs232 looks like this(handbook):
00.00.0000 00:05:30 4 363.8 0.37 134 226.1 0.53 103 23
00.00.0000 00:05:40 4 366.0 0.39 142 226.1 0.53 112 23
00.00.0000 00:05:50 4 359.5 0.41 147 226.1 0.53 116 23
00.00.0000 00:06:00 4 369.8 0.42 155 226.1 0.58 118 23
so I guess from the times its every ten seconds. (the second column is the timestamp)
The Converters are all in one place (the first is like 25meters from the last(which is like 27yards)) I got an arduino plus an ethernet shield. I wrote a client program which can successfully send data to a server via internet.
The "only" thing I got a real problem(still in planing phase) is to get all the signals to the arduino, cause I dont want to set up 40 arduinos.
the traffic is pretty low like 50-80 characters per transmitted data set.(per converter)
and
so I guess from the times its every ten seconds
Do not exactly mix do they?
You have got 800 characters per second from each sensor which is the equivalent of 8K baud. That means a 9600 baud serial link is transmitting at full belt almost all the time. If you then have 40 devices doing this you have 32K bytes of data per second to process and forward.
If I have that right it sounds like a total non starter to me with one arduino.
So...
You're keeping an eye on something.
That something has 40 "things", each of them spewing serial data, non-stop.
It might be possible to feed all 40 signals to a "switch", and forward just one of the serial streams at a time to the "harvesting" Arduino. It would control the switch....
Watch first stream, until sensible message extracted.
Switch to next stream
Watch until sensible message extracted
Switch to next....
Until all streams have been SAMPLED
Send report on what has been seen
Go back to start.
===
You wouldn't see every message from every converter... but you'd have an idea of how they're doing.
Satisfactory? If so, we can start working on how "the switch" might be built.
one line is one set of data! one line contains 54 characters.
the timestamp says if i get it right mm.dd.yyyy hh.mm.ss
rom the first to the second line the timetiffrence is 10 seconds.
in the manual it says that the converter uses 9600 as baudrate.
@tkbyd: If i understand correctly you mean that I should use like analog multiplexors. receive one signal switch to the next etc.
If I got this right with the timestamp I would get the signal from each converter every 400 seconds. Thats a pretty long time between signals.
and asuming that they give the signal exactly at the same time.