IEC PAS 62030:2004 pdf download Digital data communications for measurement and control – Fieldbus for use in industrial control systems – Section 1: MODBUS® Application Protocol Specification V1.1a –
The status of outputs 27-20 is shown as the byte value CD hex, or binary 1100 1101. Output27 is the MSB of this byte,and output 20 is the LSB.By convention, bits within a byte are shown with the MSB to the left, and the LSB to the right.Thus the outputs in the first byte are ’27 through 20 from left to right. The next byte hasoutputs ’35 through 28, left to right. As the bits are transmitted serially, they flow from LSB toMSB: 20 …27, 28 …35, and so on.
in the last data byte, the status of outputs 38-36 is shown as the byte value 05 hex, or binary0000 0101. Output 38 is in the sixth bit position from the left, and output 36 is the LSB of thisbyte. The five remaining high order bits are zero filled.NOTE The five remaining bits (toward the high order end) are zero filled.
02(0x02) Read Discrete Inputs1.6.2
This function code is used to read from 1 to 2000 contiguous status of discrete inputs in aremote device. The Request PDU specifies the starting address, ie the address of the firstinput specified, and the number of inputs. ln the PDU Discrete lnputs are addressed startingat zero. Therefore Discrete inputs numbered 1-16 are addressed as 0-15.The discrete inputs in the response message are packed as one input per bit of the data fieldStatus is indicated as 1= ON: 0= OFF. The LSB of the first data byte contains the inputaddressed in the query. The other inputs follow toward the high order end of this byte. andfrom low order to high order in subsequent bytes.if the returned input quantity is not a multiple of eight, the remaining bits in the final data bytewill be padded with zeros (toward the high order end of the byte). The Byte Count fielospecifies the quantity of complete bytes of data.
The status of discrete inputs 204–1 97 is shown as the byte value AC hex, or binary 1 01 0 1 1 00. Input 204 is the MSB of this byte, and input 1 97 is the LSB.
The status of discrete inputs 21 8–21 3 is shown as the byte value 35 hex, or binary 001 1 01 01 . Input 21 8 is in the third bit position from the left, and input 21 3 is the LSB.
NOTE The two remaining bits (toward the high order end) are zero filled.
IEC PAS 62030:2004 pdf download
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