Appendix D: Timing & Performance
124 (136)
D.2.4
Event Based Process Data Delay
“Read process data delay” is defined as the time from when the last bit of the network frame
has been received by the network interface, to when the RDPDI interrupt is asserted to the
application.
“Write process data delay” is defined as the time from when the application exchanges write
process data buffers, to when the first bit of the new process data frame is sent out on the
network.
The tests were run in 16-bit parallel event mode, with interrupts triggered only for new process
data events. Eight different IO sizes (2, 16, 32, 64, 128, 256, 512 and 1024 bytes) were used in
the tests, all giving the same test results.
The delay added by the PHY circuit has not been included, as this delay is insignificant com-
pared to the total process data delay.
Parameter
Description
Delay (min.)
Delay (typ.)
Delay
(max.)
Unit
T101
Read process data delay
-
-
228
ns
T102
Write process data delay
-
-
170
ns
NP40
Anybus
Host
connector
Host Application
Ethernet
PHY
Ethernet
Trafo
Ethernet
connector
Ethernet
Network
Read process data delay
Fig. 5
NP40
Anybus
Host
connector
Host Application
Ethernet
PHY
Ethernet
Trafo
Ethernet
connector
Ethernet
Network
Write process data delay
Fig. 6
Anybus
®
CompactCom
™
40 EtherCAT
®
Network Guide
SCM-1202-034 1.1