Multi Drop Network

Hi Experts,

I am very new to industrial automation domain. I have a couple of question. I thankful to all if you can clarify some of the things

Our customer has set of devices which are used in the industry. Currently they support Modbus and Hart communication. We are using OPC server and a client Application which is also developed by our customer. Currently the both OPC server and Client lack in Multidrop connection. We are yet to provide support for Multidrop network.

I am in the position to design the system to support Multidrop connection. All I know is, we can specify the port address in the modbus protocol before sending any message and also the device will reply back with the same port address. I am more concerned about data collison. Suppose say, I connected to two devices (Device 1 and Device

2) through multi drop connection.

Now My client application wants to trend the data received from Device

1 and Device 2. Is it possible? Are they any possible data collison..

Please let me know if you need more information..

Regards,

Krish

Reply to
krish.istream
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Hi Experts,

I am very new to industrial automation domain. I have a couple of question. I thankful to all if you can clarify some of the things

Our customer has set of devices which are used in the industry. Currently they support Modbus and Hart communication. We are using OPC server and a client Application which is also developed by our customer. Currently the both OPC server and Client lack in Multidrop connection. We are yet to provide support for Multidrop network.

I am in the position to design the system to support Multidrop connection. All I know is, we can specify the port address in the modbus protocol before sending any message and also the device will reply back with the same port address. I am more concerned about data collison. Suppose say, I connected to two devices (Device 1 and Device

2) through multi drop connection.

Now My client application wants to trend the data received from Device

1 and Device 2. Is it possible? Are they any possible data collison..

Please let me know if you need more information..

Regards,

Krish

Reply to
krish.istream

Krish,

There must be one node in the network acting as master which can be the computer connected to the network. Master sends packet to device1. All device in the network get the packet. A device processes the packet after seeing destination in the packet match with him. All others ignore. No device initiates communication except master. A device responds only if asked to. A device responds within constant finite time interval. master asks only one device at a time. master goes in round robin for all. If everything is developed properly as above, no collisions :) For other cases keep finding and fizxing as they come.

Thanks

- Surinder

Reply to
surindersingh

Multidrop networks have the additional feature that a packet or a stream can have multiple destinations. This is usefull for audio or video conferencing. Of course there cannot be replies to multicast packets.

Rene

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Reply to
Rene Tschaggelar

Surinder,

Thanks a lot..

Regards,

Gopal

Reply to
krish.istream

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