NOVUS DigiGate Profibus - Manual (Page 10)

DigiGate Profibus
NOVUS AUTOMATION 10/11
Control Register
Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
RD WD WT1 WT0 res res RCD1 RCD0 SA7 SA6 SA5 SA4 SA3 SA2 SA1 SA0
• Bit 15 – RD (Request Data Valid) - This bit is inverted by the Profibus master when valid data are to be
read. When the gateway is in not reset state (RS0=0, RS1=0), the master must mandatorily invert this bit for
resetting the gateway. Otherwise the inversion will not be necessary for updating the data; however, it will be
useful to confirm updating.
• Bit 14 – WD (Write Data) - This bit is inverted by the Profibus master when a writing operation is to be
executed in the gateway.
• Bit 13 e Bit 12 – WT1, WT0 (Write Type) – the Profibus master will indicate through these bits the type of
writing associated to bit 14.
00 - the entire table shall be transferred to the Modbus network.
01 - only those table values shall be transferred to the Modbus which have been changed since the last
writing operation.
10 - a writing operation will be executed in the table, but no value shall be sent to the Modbus network.
11 - reserved
• Bit 11 – reserved
• Bit 10 – reserved
• Bit 9, Bit 8 - RCD1, RCD0 (Request connect/disconnect) – A user disconnected block will remain
disconnected until a block reconnection request is sent or until a DigiGate is reset.
Request for disconnection / reconnection – will be executed by a request for writing through WD
(has higher priority than writing in table)
00 - No operation
01 - Disconnect device
10 - Reconnect device
11 - Reserved
• Bit 7 a Bit 0 – SA7 to SA0 (Slave Adress)
Slave address related to Bit9 and Bit8
Usage hints:
• Use the bits of the status and control registers for correct operation of the device.
• Before performing a writing operation, it is recommended to check the state of the Profibus connection by
changing the RD pin (control register) and later checking the DV pin (status register).
• After having established the connection to the Profibus network, execute the entire output table writing
(WT1=0 and WT0=0) as the first writing operation.
• The best way of assuring that a writing operation has been executed correctly is verifying the registers after
the writing operation is done.