Ethernet/IP bus interface for DIOLINE20 Vers. 1.00
Functional description
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4.3.4 I/O design
Both buses run independently and non-synchronised to each other.
The internal I/O cycle time to transmit the buffered bas data to the other respective bus is 10 ms (the
time is calculated from the minimum transmission time on the L-Bus and the maximum RPI for
Ethernet/IP).
The L-Bus throughput is calculated as:
N
bytes gross
= 2 * N
I/O bytes
+ 5
T
LBus frame
= T
bytetime
+ T
gap
T
bytetime
= N
bytes gross
* 8 * 1 µs (where SPI Clock = 1 MHz; 8 bits/byte)
T
gap
= N
bytes gross
* 40 µs + 2 ms (where byte gap = 40 µs/byte; frame gap = 2 ms/frame)
e.g. where N
I/O bytes
= 80 follows:
T
L-Bus frame
= 165*8 µs + 165*40 µs + 2 ms = 1.32 ms + 6.6 ms + 2 ms < 10 ms
The theoretical maximum delay time between physical event and reaction on the Ethernet/IP network
is:
T
maxdelay
= T
L-Bus frame
+ T
I/O cycle
+ T
RPI
+ T
latency
T
maxdelay
= 10 ms + 10 ms + T
RPI
+ x µs
T
maxdelay
≈ 20 ms + T
RPI
The theoretical minimum delay time is:
T
mindelay
= T
RPI
+ T
latency
T
mindelay
≈ T
RPI
