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Configuration
5.4
Configuring the Lock Time
The CAN transceiver transmits data and receives these transmitted data again after a certain
delay, the so-called loop delay. For example, if the transceiver transmits a dominant bit and after
that a recessive bit, the transceiver only sees the recessive bit in its receive output after the loop
delay. The size of the loop delay depends on several factors, like for example the number of CAN
nodes in the network. The higher the capacity load is, the higher is the loop delay. To avoid bit
errors caused by this delay, the configured lock time must be higher then the loop delay.
Observe, that the setting depends on the bit rate and the capacitive load of the network
►
(the higher the capacity load, the higher the value).
Configure the lock time with DIP switch S302 (4).
►
►
Observe the following reference values:
–
for networks with less than 32 nodes the minimum lock time is about 300 ns
–
for networks between 32 and 64 nodes the minimum lock time is about 500 ns
–
for networks with more than 64 nodes the minimum lock time is about 1 μs and with
this setting the bit rate is limited to maximal 500 kbit/s
Valid Lock Time Combinations
S302-1
S302-2
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ON
ON
ON
ON
ON
ON
ON
CAN Repeater User Manual
S302-3
S302-4
Lock time in ns (tolerance ±10 %)
OFF
OFF
100
OFF
ON
300 (default)
ON
OFF
500
ON
ON
800
OFF
OFF
1000
OFF
ON
1300
ON
OFF
1500
ON
ON
1800
OFF
OFF
2000
OFF
ON
2300
ON
OFF
2500
ON
ON
2800
OFF
OFF
3000
OFF
ON
3300
ON
OFF
3500
ON
ON
3800
9 (22)
4.01.0067.20000 3.4 en-US
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