Communication C3I22T11302 192-120114 N5 C3I22T11 June 20085.2.3. Binary recordThe binary record with block securing is based on 5 different telegrams: 2 request telegrams which the control sends to Compax3 and 3 response telegrams which Compax3 returns to the control.Telegram layoutBasic structure:Start code address Number of data bytes - 1 Data block securingSZ A L D0 D1 ... DnCrc(Hi) Crc(Lo)The start code defines the frame type and is composed as follows:Bit 7 6 5 4 3 2 1 0Frame type Frame identification PLC Gateway addressRdObj Read object 1 0 1 0 x 1 x xWrObj Write object 1 1 0 0 x 1 x xRsp Answer 0 0 0 0 0 1 0 1Ack Positive command acknowledgement 0 0 0 0 0 1 1 0Nak Negative command acknowledgement 0 0 0 0 0 1 1 1Bits 7, 6, 5 and 4 of the start code form the telegram identification; Bit 2 is always”1”.Bits 3, 1 and 0 have different meanings for the request and response telegrams.The address is only necessary for RS484.-> Compax3 the address bit (Bit 0 = 1 ) shows if the start code is followed by an address(only for RS485; for RS232 Bit 0 = 0) the gateway bit (Bit 1 = 1) shows if the message is to be passed on.(Please set Bit 1 = 0, as this function is not yet available) the PLC bit (Bit 3 = 1 ) allows access to objects in the PLC/Pop formatU16, U32: for integer formats (see bus formats: Ix, Ux, V2)IEEE 32Bit Floating Point: for broken formats (bus formats: E2_6, C4_3, Y2, Y4;without scaling)With Bit 3 = 0 the objects are transmitted in the DSP format.DSP formats:24 Bit = 3 Bytes: Integer INT24 or Fractional FRACT2448 Bit = 6 Bytes: Real REAL48 (3 Byte Int, 3 Byte Fract) / Double Integer DINT48/ Double Fractional DFRACT48Request telegrams
