FX3u Modbus Register Help

[skyfox 5]

Hello all, Trying to get my head around this on how to relate FX3u Modbus register numbers to Modbus standards. For instance....... Modbus standard register numbers for Reading Input registers from a device (address) starts at 30xxx. Mitsubishi range allocation (for FX3u-485ADP-MB) for input register data addresses are in the range of 0000h to A7C7h ( 0 to 42951). According to MODBUS standards, registers addresses 40xxx are for holding register data. So that would mean my MITSUBISHI input registers are ovelapping in to holding register address space. Am I wrong on this assumption? So how do I go about reading the data, for example: A7C7h from the MITSUBISHI Modbus Slave from a MODBUS (non Mitsubishi) master that follows the MODBUS standards for data registers. What would be the command format from the master to read Input register A7C7h from Mitsubishi? Am I not looking at this the right way. Am I Just suppose to send the Read input register command (FC=04) along with the address A7C7h? Any and all help would be grately appreciated. Thanks.

[kaare_t 155]

Yes, you would send "Read input register command (FC=04) along with the address A7C7h". Modbus devices can be either 30xxx or 30xxxx, and in the FX3U you have more than 9999 addresses therefore the address space is 30xxxx (or 40xxxx).