Intelligent Modbus Gateway Required

For searchers in the future:

Two additional solutions offered here:
https://control.com/forums/threads/intelligent-modbus-gateway-required.49384/

danw said:

Post #1: "I can not change the program of existing PLC"

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Well. Post #12. One small PLC between original PLC and equipment.
Then on post # 13 OP asked how it would poll 16 devices.

Lare said:

Well. Post #12. One small PLC between original PLC and equipment.
Then on post # 13 OP asked how it would poll 16 devices.

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Hi,

I guess you are not getting the point here regarding the scenario. Let me try again here:

In principle, every PLC com port will have a unique Modbus Address. Right?

How will a new PLC read 16 different Modbus Slave Address Requests via a single com port from existing PLC? I am unaware of any PLC that can respond to multiple addresses via a single com port. I hope its clear what we are trying to achieve here. Anyway Redlion Datastation can do this job as confirmed by their technical support. So I am going with that.

Additionally as danw pointed out. I posted same question on another forum and there are two more suggestions there. Below is the link:
Two additional solutions offered here:
https://control.com/forums/threads/i...equired.49384/

You are right, it should need 16 different slave ports.
Changes are that there isn't much devices to choose or you need 16 different parts or some other devices between.


Why original PLC modbus master program can't be changed?

Lare said:

You are right, it should need 16 different slave ports.
Changes are that there isn't much devices to choose or you need 16 different parts or some other devices between.


Why original PLC modbus master program can't be changed?

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Anything with 16 ports can do the job. But that's not an effective solution. That is where Redlion Gateway will be handy. I have not tested it yet, but I have been told by an expert that it can do this job via a single port.

Actually PLC was installed by a vendor who is not giving access to PLC logic project for modifications so we have fixed addresses and registers from PLC side and have to change obsolete field devices via a gateway.

You might look into HS AnyBus gateway

Modbus is transmitted over serial lines between devices. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Master and a Slave. The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. MODBUS is a commonly used industrial communications protocol. It allows the exchange of data between PLCs and computers. It was originally designed for Modicon (Schneider Electric) PLCs but has become widely used by many PLC manufacturers and industrial networks, Thank You!!

Rao Shaheryar said:

Modbus is transmitted over serial lines between devices. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Master and a Slave. The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. MODBUS is a commonly used industrial communications protocol. It allows the exchange of data between PLCs and computers. It was originally designed for Modicon (Schneider Electric) PLCs but has become widely used by many PLC manufacturers and industrial networks, Thank You!!

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Errrrrrmmmm OK. Have you read this thread and the OP's question ?