Timing - Leuze electronic DDLS 200 Technical Description

DeviceNet / CANopen

9.7.2 Timing

Telegram delay from segment to segment
• typical run-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
1 • Telegram length
1 • Number of bits • 0.5µs
Processing
Typ. gross delay
The maximum delay is dependent on various boundary conditions:
• bus load
• message priority
• history
• sorting active / not active
If a slave is addressed by a subscriber 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 configuring the system.
48
= 8µs)
47 bits
32 bits
8 bits
87 bits
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
696µs 1 • Telegram length
44µs 1 • Number of bits • 0.5µs
45µs Processing
785µs Typ. gross delay
DDLS 200
) + 10µs
bit
) + 45µs
bit
= 1µs)
bit
47 bits
64 bits
12 bits
123
bits
Leuze electronic
123µs
62µs
10µs
195µs