Terumo CDI 550 Operator's Manual page 155

C-24 appendix c
'7' Arterial
Flow
Auto Inter-
val
CRC Information.
the 8-bit CRC is generated using the following algorithm
const uchar CPIP_crc_table[]=
{
0x00, 0xcd, 0xd9, 0x14, 0xf1, 0x3c, 0x28, 0xe5,
0xa1, 0x6c, 0x78, 0xb5, 0x50, 0x9d, 0x89, 0x44
};
unsigned char CPIP_crc(uchar *start_adr, int count)
{
int i;
uchar crc,idx;
uchar *byte_ptr;
byte_ptr = start_adr ;
crc = 0 ;
for (i=0 ; i<count ; i++ )
{
idx=( crc^(*byte_ptr) ) & 0x0f ;
crc = ( (crc>>4 ) & 0x0f)^CPIP_crc_table[idx];
idx=( crc^(*byte_ptr >> 4)) & 0xf ;
crc = ( (crc>>4 ) & 0xf)^CPIP_crc_table[idx];
++byte_ptr;
}
return(crc);
}
Sent by the CDI System 550 to a pumping system, this sets
the interval, in seconds, that the CDI System 550 wants
Arterial flow. The pumping system shall respond with an
Acknowledge packet telling the CDI System 550 the nego-
tiated value for Arterial Flow. A 0 value indicates that no
unsolicited flow values shall be sent, and the CDI System
550 will send a "Get 6" packet to get the Arterial Flow. The
CDI System 550 always requests that Arterial Flow be sent
every 6 seconds, but will use the value sent back from the
pump as a basis for its timeout value for Arterial Flow. For
example, if the CDI System 550 sends a S712, indicating
that the Arterial Flow Auto Interval shall be 12 seconds, the
expected response from the pump would be a K0S712,
where the S712 is the data portion of the packet. This would
then tell the CDI System 550 that flow will be sent every 12
seconds, and the timeout will be 3 x 12 or 36 seconds.