Modbus Problem

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Thread Starter

Gonzalo Duran

Hello.
my problems is how to convert a serial data (rs232c) in the modbus rtu data

I have a laser sensor that delivers data via RS232C as I can make these data modbus rtu to be read by kepware
 
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Bob Peterson

Just because it is rs232 does not mean you can access it via modbus
protocol.

There might be some kind of adapter available from the sensor manufacturer for this purpose.
 
hi
Bob is right. even though your sensor has RS232C port - it doesn't mean it supports Modbus protocol for data sharing.

pls check your sensor specs.

i personally doubt it has Modbus capability.

if my guess is right. what u can do is connect your laser sensor to a small PLC which supports Modbus protocol eg. Moxa IOlogik series.

may i know the distance between your sensor and your PC containing Kepware's KepserverEx ?

distance plays a role in selecting correct Modbus protocol.
 
F

Fabian Quiñones

Hello,

Do you know some converter (company) for this job?? Serial 232 to Modbus RTU??

Thanks.

Regards from Chile.
 
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Fred Loveless

Hi,

What is the make and model of the sensor? If it does not support Modbus it is very likely that Kepware's UCON driver can talk to it.

Contact Kepware Technical Support and ask to be connected to me.

Fred Loveless
Senior Application Engineer
Kepware Technologies
http://www.kepware.com
 
Hi Gonzalo Duran,

If the laser sensor supports Modbus RTU (I don't think so), it should be easy, as you probably only need a RS232-to-RS485 converter.

I suspect however, that the laser sensor will send it's information in ASCII and If so, you will need a gateway. I work for a company called HMS and we have a product called Anybus Communicator that is ideal:
Modbus RTU-to-serial (ASCII):
http://www.anybus.com/support/support.asp?PID=317&ProductType=Anybus Communicator

My 2 cents
 
Think of RS-232 as the communication interface and Modbus RTU as the communication language. (RS-232 is a physical wire and Modbus RTU is a protocol.) If the wiring between your laser sensor doesn't match the input of your PLC/ PC, then you need a converter. If the protocols don't match, you will need a gateway.

Once you find out the exact protocol of your laser sensor you can use the chart here, from ICP-DAS, to find the right converter/ gateway:

http://www.icpdas-usa.com/advancedsearch.html#protocolconvertertable

Also, you didn't specify if your sensor had a data acquisition device attached to it. There are data acquisition modules that can read the data from your sensor and transmit it over your desired, protocol. Since you specified Modbus RTU, here are some data acquisition devices that communicate over RTU:

http://www.icpdas-usa.com/search-result-daq.php?ModbusRTU=Modbus+RTU&submit=Search
 
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