Pixsys CNV510-PNET-RTU-A, User Manual

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pag. 20
MODBUS DIAGNOSTIC OVER PROFINET:
During the normal functioning of the device, if all the programmed Modbus requests have received a valid reply (not an exception error), every PROFINET frame has the "Data
Status" byte at the value of 0x35.
Otherwise, if at least one Modbus reply is not valid, the "Data Status" byte assumes the value 0x15; that means "Problem Indicator".
If this happens, using the port 5000 there is a UDP message that is possible to send in order to understand which Modbus modules have generated that error.
This command is described in the section "Advanced Functions" under the “B2 command”.
Moreover, it is possible to save the Modbus Diagnostic on Output PROFINET array using the field “Diagnostic” of the section “Set Communication”.
In this case, the status of each Modbus request defined in the section “Set Access” is saved starting from the byte of the PROFINET array defined in the section “Set
Communication”.
Each bit will represent the status of a Modbus request:
If for a request the converter receives a correct response, the status bit is put to ‘0’;
If for a request the converter receives a wrong response or it doesn’t receive any response, the status bit is put to ‘1’.
Example:
In the section “Set Access” are defined 8 Modbus reading requests (“Modbus Read” table) and 8 Modbus writing requests (“Modbus Write” table). The Modbus reading requests
are working and the Modbus writing request are not working.
The status bits of the Modbus Diagnostic on PROFINET will be:
Byte x Byte x+1
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
where ‘x’ is the starting byte of the PROFINET array where the Modbus diagnostic is saved.