I have connected my slave and RS-485 using serial connection and using my computer as master device. I'm able to poll but I cant figure out which registers I'm polling as shown in image 1. I tried to pull the registers as shown in the manual (image 2) but I can pull only one register at a time.

Is there any way to poll all the registers I need in the same time?

modbus connected to Rs-485 pulling address i need


Your problem is related directly to a windows application called Modbus Poll. It is Modbus master simulator.

Anyway, you are actually reading first 10 registers in your first screenshot. The second column name (next to Alias) contains the Start Address of registers you wish to read (in your case it's 0). And then you have your quantity of registers that you wish to read (10 in your example) represented in the table.

In this application to change start addresss and quantity you should go to Setup->Read/Write Definition and there select your slave device ID, function code (choose function code either 0x03 or 0x04 to read holding registers or input registers, they may not be the same in some devices), start address and quantity.

  • \$\begingroup\$ GAttuso thanks answering i cant access all the registers in the same time if i give address 3 it only displays all the register that has this address but need all of them in the same page as shown in the image 1. \$\endgroup\$ – mike4766 Oct 14 '15 at 19:34
  • \$\begingroup\$ Mike, the registers can only be read in a contigious blocks. And for each address there is exactly one register. That means if you send request with start address = 3 and quantity = 4, you will get values of registers with address 3,4,5, and 6. \$\endgroup\$ – GAttuso Oct 15 '15 at 5:13

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