Time Behavior - Leuze electronic DDLS 200 Series Original Operating Instructions

DeviceNet / CANopen

9.7.2 Time behavior

Telegram delay from segment to segment
• Typical propagation time delay of the messages in one direction
• Calculated with 10% stuffing bits
Message memory not sorted (FIFO)
Number of bits in the telegram • 1.1 • (0.5µs + T
Message memory sorted
Number of bits in the telegram • 1.1 • (0.5µs + T
Example 1: DeviceNet
• 125kBit/s (  T
bit
• 4 bytes of data
• Message memory sorted
Protocol overhead
Data
Stuffing bits
 Number of bits in the telegram 87 bits
1 • telegram length
1 • Number of bits • 0.5µs
Processing
Typ. total delay
The maximum delay depends on various boundary conditions:
• Bus load
• Message priority
• History
• Sorting active / not active
If a slave is addressed by a participant along an entire segment and expects an answer, twice the
propagation time must be planned for (twice the optical path).
If multiple optical paths are used in a system, the delay times may be added (depending on the con-
stellation in the bus).
The increased delay times must be taken into consideration when parameterizing the system.
48
= 8µs)
47 bits
32 bits
8 bit
Example 2: CANopen
• 1MBit/s (  T
• 8 bytes of data
• Message memory not sorted (FIFO)
Protocol overhead
Data
Stuffing bits
 Number of bits in the telegram 123
696 µs 1 • telegram length
44 µs 1 • Number of bits • 0.5µs
45 µs Processing
785 µs Typ. total delay
DDLS 200
) + 10µs
bit
) + 45µs
bit
= 1µs)
bit
47 bits
64 bits
12 bits
bits
Leuze electronic
123µs
62 µs
10µs
195µs