The communication load factor is a value obtained by dividing the number of communication packets that an EtherNet/IP device sends/receives per second by a cyclic communication allowable communication band (the number of packets that can be sent/received per second).
The load factors of FP7 and each adapter device should be 100% or less.
Calculation procedures
Calculating the number of communication packets sent/received per second (pps)
Calculate from RPI. * pps = 1000 ¸ RPI [ms]
When the Change of State (COS) trigger is set, it is calculated as a communication cycle RPI x 1/4.
ExampleFor a connection when RPI is 0.5 [ms]
1000 ¸ 0.5 = 2000 pps
For a connection when RPI is 0.5 [ms] and the COS trigger is set
1000 ¸ (0.5 x (1/4)) = 500 pps
Calculating the cyclic communication allowable communication band (pps)
Calculate from the data size per packet and EDS information [Capacity] for FP7
Data size per packet
Connection transmission/reception data size = Raw data size + 32-bit header size
Without 32-bit header: 2 bytes
With 32-bit header: 6 bytes
FP7_EDS [Capacity] definition
2 to 510 bytes: 10000 pps
511 to 1450 bytes: 5000 pps
ExampleWhen the connection transmission raw data size is 256 bytes without 32-bit header
(256 + 2) = 258 bytes £ 510 Þ 10000 pps
When the connection transmission raw data size is 512 bytes with 32-bit header
(512 + 6) = 518 bytes ³ 511 Þ 5000 pps
Calculating the unit communication load factor from the number of sent/received packets (pps) and sent/received data size
ExampleWhen the sent data size is 256 bytes and the received data size is 36 bytes
No. of sent packets (2000 pps) ¸ 10000 pps x 100% = 20%
No. of received packets (125 pps) ¸ 10000 pps x 100% = 1.25%
ÞThe unit communication load factor is (20% + 1.25% = 21.25%).