User Manual

DigiGate Profibus
NOVUS AUTOMATION 8/11
Tables for data interchange
Reading Table:
Fig. 8 – Reading of the Modbus slaves by the Profibus master
The Reading Table or Input Table contains the values read of the Modbus network equipment registers (according to
the equipment configuration), besides a status register (1st position of the table). The table corresponds to the field of
data sent from the DigiGate to the Profibus master. Its format is as follows:
Position 0
Status Register – in details as follows
Position 1
Register value of the equipment in the Modbus network
Position 2
Register value of the equipment in the Modbus network
.................
.......................................................................................................
Position 121
Register value of the equipment in the Modbus network
At the equipment configuration the table positions are associated to the Modbus registers which are to be made
available. All positions are values of 16 bits. The table size is preset (122 words of 16 bits), the size of the data block
sent to the Profibus network, however, is configurable and may not correspond to the table in its totality.
Status Register
Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
DV WDN RS1 RS0 ET2 ET1 ET0 EQ AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
• Bit 15 – DV (Data Valid) – This bit is inverted, becoming equal to bit 15 of the control register when the input
table has been updated.
• Bit 14 – WDN (Write Done) - This bit is inverted, becoming equal to bit 14 of the control register when a
writing operation has been performed in the Modbus network.
• Bit 13, Bit 12 – RS1, RS0 (Reset State)
00 – Gateway not reset
01 – At least one reading scan operation of the Modbus already executed
10 – First writing operation performed (invalid)
11 – First reading and first writing operation already performed.
• Bit 11, Bit 10, Bit 9 - ET2, ET1, ET0 (Error Type)
000 - No error
001 - Parity error
010 - CRC error
011 – Byte Time out error – response not complete
100 – Response Delay error – no response
101 - Exception error– probable incoherency in the message requested to the slave