Modbus-rtu multiple slave address

Anybus Support Embedded
#1

Hi,

I wish to use the Anybus CompactCom Modbus RTU to reply to different slave addresses.

I implemented the Modbus Forwarding Message but I don’t see any request sent to a different address than the one in the Network Configuration Object (04h) Instance #1, ‘Device Address’.

I suppose the module is filtering the messages in the bus not destined to that address. Is there a way to disable this filter and receive every valid message in the host application?

Thank you,
Ramon

#2

Hello Ramon,

I am not aware of a way to add additional node addresses for the device It is designed around the network configuration object that only has the singe device address.

Regards,
Deryck

#3

Hi Deryck,

Thank you for your answer.
Unfortunately this will force to dynamic modbus registers which I don’t like (but I need more than 65535 registers).
I think that setting a slave address of 255 and accepting every message (message forwarding enabled of course) could be very useful

Best Regards,
Ramon

#4

Hello @ramon.effegi,

I’m not sure what to suggest here. More then 65535 is a lot of data, can you provide any additional details on what you are doing maybe I can make some suggestions.

Deryck

#5

Hi Deryck,

I need to gather the status of 15000 sensors per device, up to 30 devices and make it available via modbus

The sensors to map are 30x15000=450000.

If the module could receive request for every slave I could map the sensors to 30 slave addresses using 15000 registers each.
This way the customers could map everything with a fixed configuration on the scada/hmi

Thanks for the help

Ramon

#6

Is this a new host application you are developing for this? Are you saying 15000 sensors on the host side of the compactcom?

The compact com is designed to act as one modbus RTU slave with 512 holding registers and 256 input registers. I am not sure the Compactcom would be able to handle as much data as you are expecting.

Have you discussed this application of the device with your sales manager?

Deryck

#7

I managed to use all the 0xFFFF addresses only by using the Modbus Forwarding Message mode.

I have to parse the received message and build the proper reply but this way all the registers are available

Ramon