MoTeC ACL VIM - Manual (Page 73)

MoTeC Appendices 69
Appendix F: CAN Bus Bandwidth Limit
The total available CAN bandwidth available on a single CAN bus is
1 Mbit/sec.
The bandwidth used by the total of all devices on a particular CAN bus must
not exceed approximately 90% of this value (900000 bits/second)
If the total bandwidth required exceeds this specification then some devices
should be connected to the second CAN bus.
Note ACL Manager will warn if the bandwidth is likely to be exceeded.
VIM
Approximate Bandwidth = Total Measurement Rate (samples/sec) x 30 (bits
per sample)
Note The Measurement Rate for each input is equal to the logging rate for
that input or 50 Hz, whichever is higher.
Example Calculation
4 channels at 2000 Hz
20 channels at 500 Hz
40 channels at 20 Hz (Occupies 50 Hz)
Calculation:
Total Measurement Rate = 4 x 2000 + 20 x 500 + 40 x 50 =
20000 (samples/sec)
Approximate Bandwidth = 20000 x 30 = 600000 (bits/sec)
E888/E816
Device on first CAN Address
Bandwidth = 145000 (bits/sec)
Device on second CAN Address
Bandwidth = 55000 (bits/sec)