Honeywell CD3000M-1PH, Руководство пользователя

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Honeywell CD3000M-1PH from 125A to 700A User’s Manual
www.honeywell.com/imc 38
9.2.3 C Language CRC 16 Example
static short CRC16 (unsigned char *p_first,unsigned char *p_last)
{
unsigned int crc=0xffff;
short j;
for (;p_first<=p_last;+)
{
crc ^= *p_first;
for(j=8;j>0;j--)
{
if(crc & 0x0001)
{
crc = crc >> 1;
crc ^= 0xA001;
}
else
{
crc = crc >> 1;
}
}
}
return (crc);
}
9.2.4 Read Holding Registers (Read n Words) – Function 03
The message sent to the Controller to obtain the value of one or more registers comprises the
following eight bytes:
Addr. unit Func. Address
1° word N° of Word CRC 16
3
3Hex HI LO HI LO HI LO
The normal reply will echo the first two characters of the message received followed by a single-
byte data byte count (which will not include itself or the CRC).
For this message, the count value equals the number of parameter values read multiplied by two.
Following the byte count, the specified number of parameter values are transmitted, followed by the
CRC16 bytes:
Addr. unit Func. Cont. 1° Value Last Value CRC 16
3
3Hex HI LO HI LO HI LO