User guide

CobraNet Programmer’s Reference

Management Interface Variable Reference

6.2.4 PhysAddress

A 48-bit Ethernet media access control (MAC) address.

24-bit HMI: Data is stored in the most-significant 16 bits of 3 consecutive memory

locations as illustrated below. The least-significant 8 bits of each location are read as zero

and must be written as zero.

32-bit HMI: Data is stored in two consecutive words as shown below. A third word is

unused and reserved for addressing compatibility with 24-bit platforms.

6.2.5 TimeTicks

TimeTicks is an integer encoding for time durations in units of 100ths of a second.

24-bit HMI: An unsigned timer value is available in two successive 24-bit words. A 32-bit

timer value and 15-bit fractional extension are available as shown below. The fractional

extension may be used to gain additional accuracy. It may be safely ignored for most

applications.

32-bit HMI: TimeTicks value is available as two sucessive 32-bit words. A 32-bit timer

value, a 16-bit rollover, and 16-bit fractional extension are availabe as shown below. The

fractional extension may be used to gain additional accuracy. The rollover extension may

Table 12. MAC address Layout, 24-bit Platforms

MS Middle LS

Word 1

MAC byte 2 MAC byte 1 0

Word 2

MAC byte 4 MAC byte 3 0

Word 3

MAC byte 6 MAC byte 5 0

Table 13. MAC address Layout, 32-bit Platforms

MS MH ML LS

Word 1

MAC byte 2 MAC byte 1 MAC byte 4 MAC byte 3

Word 2

MAC byte 6 MAC byte 5 unused unused

Word 3

unused unused unused unused

Table 14. TimeTicks Layout, 24-bit Platforms

MS Middle LS

Word 1

Timer MS Timer MH Timer ML

Word 2

Timer LS Fractional LS Fractional MS