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ORSO2001

3 x RS485 ports...

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Dear All,

for my next project I have to manage a ModBus RTU data exchange with 57 devices by RS485 port...but the system can be enlarged in the future...where the Unistream works as master.

two of these devices has the same ID 49 and it is fixed and is not possible to change...in the others can be selected.

one port is already present in the PLC;  I know that exist the external module (UAC-02RSC) to have +1 RS485 and +1 RS232...but it would be nice have a module to have +2 RS485...exist a way to have this withou buy 2 x UAC-02RSC to have 3 x RS485?

thanks

PS: can be a solution connect a converter RS232/RS485 with the module UAC-02RSC or some problems can arise?

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Hi Orso, did you have a read of this topic and my suggestion further down to perhaps incorporate V130s into the mix?  You collate/send data from/to them with the Unistream as necessary.

One issue that you may not be aware of is that there appears to be a problem with the 232 port operations on the 02RSC module. 

Using 130 (s?) might be a cheaper, and perhaps better way around the issue, and could cover the double address issue quite easily.

cheers, Aus

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And it does seem strange that an ID of 49 cannot be changed!  That is certainly an odd number to have as a "permanent" default!  Have you played with it using a modbus/serial tool on the PC to see if you can do it through "unconventional" registers?  I work with a few sensors that supposedly need a special program to change their defaults, but once you find the code it is easy.  Sometimes there is also a locking register as well.  You change that, then you can change the ID register.

cheers, Aus

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Hi Ausman,

thanks for the answer...I will check if a register contain the ID 49 and if I can change this...but I am quite sure that is not present and that the ID49 is "fixed inside" by its program.

You are right...I didn't know that the RS232 of the 02RSC has a "problem"...thanks to have highlight this...also the UAC-02RS2  (2 x RS232) has problem?

so you are suggesting connect the unistream PLC with soresting me device and also vith a Vision PLC...this last will be connected with the others devices...uhm can be interesting...but if possible, in this case, I prefer have only one PLC.

I will update this topic after the check about the ID register.

 

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2 hours ago, ORSO2001 said:

unistream PLC with soresting me device and also vith a Vision PLC

"soresting" I didn't quite interpret, sorry. 

Have one of each doing 485 comms, with the vision reporting collated data to the Unistream and being "instructed" what to send out by the Unistream.  It all depends a little on what speeds are needed for monitoring all 57 units.  Using both a vision and unistream should effectively halve this time against doing it with just one plc, if you are planning to only switch through them sequentially...1-57 at a fixed rate etc.

Aus

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Quote

"soresting" I didn't quite interpret, sorry. 

Eh Eh...sorry...my brain was off...I meant: connect the unistream PLC with some devices and also with a Vision PLC...and the Vision with others devices...

the slaves can works or at 9600 or at 19200 baud rate...

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ok...I think that I tried all the possible register...and I don't found any that can be releated with the  ID...as I wrote I am quite sure that is a fixed ID because these two devices is a part of a "static" system that always manage these as device 49 and only one can be present in the system...also are present others static ID like 50, 51 , 52 etc.

said this, unfortunately, the way with one or more Vision is not accepted by the owner of the project...I have to use only one PLC + HMI.

said this (2)...I have to buy a module to add the serial ports...at this point can I buy the UAC.02RS2, that has 2xRS232, and connet each port with a RS232-485 converter?...or some problems can arise?

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If you are stuck with only one plc, I really think that you'd be much better off in the long run by simply using a few 02RSC dedicated to 485.  The fewer devices in a serial link the better.  And they're likely to be less expensive than also buying a converter.

cheers, Aus

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