Multiple IP-series HMI over RS485 2W

[Vishnu]

Hello everyone

I am having trouble taking over a legacy system where they have hooked up multiple 6103ip HMI’s to a singular Delta DVPES2 PLC. The connection is daisy chained over 2W RS485. It should be possible with the screen but i for god cant figure out the connection settings.

Any help would be greatly appreciated

[Sergio Bertana]

On a 2 wire RS485 multidrop connection there must be only 1 master device. To connect multiple HMIs on the same connection the best way is to use the Modbus protocol and set the HMIs as “MODBUS Server”.

Each HMI must have its unique Station number, and the PLC must act as a master Modbus interrogating the HMIs.

[Vishnu]

The software does not allow me to add more than one connection to a COM port.

[Sergio Bertana]

Exactly you have only one connection to the serial port.

The connection is a multidrop RS485 on which the PLC acts as a Modbus master and all the HMIs act as a Modbus slave.

[Marco]

Mi trovo ora a collegare un HMI serie IP su una rete modbus RS485. La rete è composta così:
Ho un PLC della Delta come master e due slave DTC1000 della Delta collegati in RS485.
Ora ho acquistato un HMI serie IP della Weintek e volevo collegarlo per leggere i dati DTC100  sempre in RS485.

Sto impazzendo su come impostare HMI. Un DTC 1000 ha nr stazione 2 e un altro DTC1000 ha nr stazione 3. Il PLC è master e la stazione nr 1. Ora come faccio a impostare HMI in slave?

[Vishnu]

Hello Marco.

Sorry for not responding in your native language. I have had a look at your problem and question your approach to your control system.

Is there a reason why the HMI needs to directly interface with the DTC1000 data? If you have it connected to the PLC, just have the PLC periodically poll the data you require into registers in the PLC. Then the HMI can read from the PLC as normal.

From my experience, having more than two types of devices on one RS485 chain is very tricky.

There are 3 communication ports on Delta PLC. You can use each independently from one another. I.E. have DTC1000 on COM2 and HMI on COM3 or COM1.

Thirdly I would recommend buying the extension modules if you are running low on COM ports with the Delta PLCs. They plug into the PLC and interface directly with it.

[Autore]

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