WAGO 750-632 Manual

Also see for 750-632: Manual

108 Appendix WAGO-I/O-SYSTEM 750750-632 Proportional Valve ModuleManualVersion 1.3.0, valid from FW/HW-Version 01/0111.1.3.2 Data ExchangeIn the data exchange phase, the handshake byte is used in Toggle mode. Because amessage is normally larger than the data part of the transmission channel, themessage must be transferred in several cycles (fragmentation).Status Nibble Control NibbleBit 3 Bit 2 Bit 1 Bit 0 Bit 3 Bit 2 Bit 1 Bit 01 T 0x00 1 T 0x00Send fragment:The first toggle bit expected by the receiver after synchronization has the value 0.The toggle bit in the second fragment receives a 1, the toggle bit in the thirdfragment again a 0, etc. Only when the status of the toggle bit matches in thereceived status nibble is receipt of the fragment confirmed by the receiver. Onlythen can a new fragment be sent. As long as there is no confirmation, the fragmentremains unchanged in the process image.For the special case that the content of the send buffer is no longer sufficient to fillthe transmission channel completely, the transmission channel is filled with zerosto the end.Receive fragment:The control now has to confirm receipt of this fragment. Receipt is confirmed byinverting the toggle bit of the status nibble to be sent.Because the Mailbox 2.0 mechanism is full-duplex capable, data can be sent andreceived at the same time.