RS232 to analog signal

A

Thread Starter

Anonymous

Hello everyone,

Could RS232 signal be converted to 4-20mA analog signal? If yes, please how?

Thanks.
 
RS232 is digital, so if you want to convert this signal to analog there are different ways.

1. Use 4mA like a logical '0' and 20mA like '1'

2. Act like very old PC speakers. You can send via RS232 something like this (repetitively)

0011 0011 0011

and it can mean that it is [(20-4)*3/15]+4 mA

You can use a longer word to achieve more resolution.

My english is ugly, I know... but I think that people can understand it.
 
Hi,

KKsystems have a product on the market called KD485. One version of this unit takes RS232 on port 1 and converts this to 4-20mA on Port 2
Model No. KD485-ADE-232-20MA DIN rail mount, 24Vdc supply.

Hope this helps.
 
I don't think so. It's not like converting RS232 to Enet or RS232 or to some other signal. I could be wrong but I don't think so.
 
Y

Yeasir Rahul

Yes, possible.

How?
1. Use an off-the-shelf product like the one from KK Systems, mentioned by another poster.

2. If a suitable ready-made product is not available, then you can make a circuit with a micro-controller, that will receive the serial data, and then drive a DAC. Suggested parts list

A. AT89C52
B. DAC0800
C. Max232

Yeasir Rahul
VoltSmith Technology
www.voltsmith.com
 
If the data coming across the RS-232 is the Modbus RTU protocol, then there's a panel meter, the Precision Digital PD 865 Snooper which can be set up to be a slave that has the data value written to it, or a master that polls the slave for a process variable value.

The meter has a 4-20mA analog output option that retransmit its process value.

datasheet:
http://www.predig.com/download/download.asp?File=/products/datasheets/LDS865.pdf

manual:
http://www.predig.com/download/download.asp?File=/products/manuals/LIM865.pdf

Bud
 
D

DGH Tech Support

If you have control of the data format then you can consider DGH analog output modules that will convert RS-232 signals to analog voltage or current. Using properly formatted data, the D3251 will convert RS-232 data into 4-20mA current output.

http://www.dghcorp.com/analogoutputs
 
What type of serial data are you trying to send? We provide a low cost IP based controller called BarioNet that has serial interfaces, (RS232 & RS485), that can be programmed to support any serial protocol and then command an 4-20mA AO signal as necessary.

Adam
www.datanab.com
 
Um, this is not what he had in mind. Do you know what a 4-20ma signal is?

There are more than a few EIA232 to 4-20ma convertors on the market, so save yourself a lot of pain and just buy one.
 
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