Hi All,

I am facing an issue while writing the Modbus register. Suppose from PLC I have written Value 10 in the first register then on Modbus Sim, I am getting 10 value, Value 20 I am getting same value in Modbus sim but for Value 511 I am getting value 510,  for 1100 value I am getting 1096, for 1500 value I am getting 1496.  I have attached the PLC backup and a Video of the Modbus Simulation for reference. 

PLC: CPU 1510 SP-1 PN [ 6ES7510-1DJ01-0AB0]

TIA V17.

Please let me know how to solve this issue. 

Waiting for your valuable reply.

Regards,

Yogendra

Hello,

just one strange  observation and probably your problem. Your set values at VAT are overlapped as addresses, with no correct offset. If you look at your defined DB structure offsets they take 2 WORDs but you set in your VAT table values with half of address, simply wrong offsets. Then it can be easy to not have full data type access. I expect that in CLIENT block all is ok with start address of register but you set wrongly your offsets there and this is your problem. Your DB2 shows correctly how to define data in VAT with address so it starts DBD0, next DBD4 but you set address DBD2. Set all as your DB2 is defined and you can have then correct data probably. It is easy to compare addresses in DB2 (offsets) and with your set in VAT where you set values for test and for data exchange with Server.

Hi Duris,

Thanks for your quick reply. I am writing resister CRIUS®4.0 Controller. When I write some value in DBD0 address controller is not accepting the value but when I write some value in DBD2 the controller accepts the value. For reference please find attached the controller manual. Kindly refer to page no.18

Please let me know your suggestion.

Waiting for your reply.

Regards,

Yogendra G

 Hello,

YogendraK

Hi Duris,

Thanks for your quick reply. I am writing resister CRIUS®4.0 Controller. When I write some value in DBD0 address controller is not accepting the value but when I write some value in DBD2 the controller accepts the value. For reference please find attached the controller manual. Kindly refer to page no.18

Please let me know your suggestion.

Waiting for your reply.

Regards,

Yogendra G

very sry, this isn't helpful to give better help, with documentation. I don't know what data and how much you need exchange with Server and to what exact register types. If you better describe this, then it can be clear and help can be better. Next strange thing, your test shows some PC sim application and not real device so it's little bit chaotic and no possibility to understand exact problem you have. I recommend to improve Modbus knowledge for first and also standard PLC data types addressing, offsets usage. Your steps are like hit or miss what goes to nothing, in my opinion because base of problematic isn't clear to you.