Filter
Top Products
6 WIRING
6.6 Output Wiring
89
6
6.6 Output Wiring
The output wiring of the CPU module and I/O modules is explained below.
Relay output
For output specifications of the CPU module, refer to Page 21 Output Specifications.
For output specifications of the I/O modules, refer to Page 136 Output specifications.
Product life of relay output contacts
The product life of relay output contacts varies considerably depending on the load type used.
Note that loads generating reverse electromotive force or rush current may cause poor contact or welding of contacts which
may lead to considerable reduction of the contact product life.
■Inductive load
Inductive loads generate large reverse electromotive force between contacts at shutdown, which may cause arc discharge. At
a fixed current consumption, as the power factor (phase between current and voltage) gets smaller, the arc energy gets larger.
The standard life of contacts used for inductive AC loads, such as general contactors and solenoid valves, is 500,000
operations at 20 VA.
The following table shows the approximate life of a relay based on the results of an operation life test.
• Test condition: 1 sec. ON/1 sec. OFF
The product life of relay contacts becomes considerably shorter than the above conditions when the rush overcurrent is shut
down.
Please refer to the following measures regarding the inductive load.
Page 91 Contact protection circuit for inductive loads
Some types of inductive loads generate rush current 5 to 15 times the stationary current at activation. Make sure that the rush
current does not exceed the current corresponding to the maximum specified resistance load.
■Lamp load
Lamp loads generally generate rush current 10 to 15 times the stationary current. Make sure that the rush current does not
exceed the current corresponding to the maximum specified resistance load.
■Capacitive load
Capacitive loads can generate rush current 20 to 40 times the stationary current. Make sure that the rush current does not
exceed the current corresponding to the maximum specified resistance load.
Capacitive loads such as capacitors may be present in electronic circuit loads including inverters.
■Resistance load
For maximum load specifications of resistance load, refer to the following.
For output specifications of the CPU module, refer to Page 21 Output Specifications.
For output specifications of the I/O modules, refer to Page 136 Output specifications.
Load capacity Contact life
20 VA 0.2 A/100 V AC 3,000,000 times
0.1 A/200 V AC
35 VA 0.35 A/100 V AC 1,000,000 times
0.17 A/200 V AC
80 VA 0.8 A/100 V AC 200,000 times
0.4 A/200 V AC