Omron CS1D DUPLEX SYSTEM - 10-2009 Operation Manual page 533

Specifications of Basic I/O Units and High-density I/O Units
About Contact Output Units
When used in the ways shown below, there may be differences in the life expectancies of the relays.
• When using in excess of rated values
• When appropriate surge countermeasures are not taken
• When connected to a load (e.g., relay, solenoid, or motor) that generates a high counterelectromotive force
when power is interrupted
• When connected to a load (e.g., capacitor or lamp) that generates a high inrush current when power is
turned ON
In the above cases, ensure the rated life expectancies of the relays by, for example, taking the appropriate
surge countermeasures as explained in the manual, or using a switching device (as a relay) with ratings appro-
priate for the load.
Life Expectancy of CS1W-OC201/211 Relays
The life expectancy of the CS1W-OC201/211 Contact Output Unit is shown in the following diagrams. Use the
diagrams to calculate the relay service life based on the operating conditions, and replace the relay before the
end of its service life.
Note The diagrams show the life expectancy of the relay itself. Do not use a contact current, therefore, that
exceeds the maximum switching capacity specified in the specifications for each Contact Output Unit. If
a switching capacity exceeding the specifications is used, the reliability and life expectancy of other
parts will be reduced and the Unit may malfunction.
300
200
100
50
30
20
10
5
3
2
0.1
Inductive Load
The life of the Relay varies with the load inductance. If any inductive load is connected to the Contact Output
Unit, use an arc killer with the Contact Output Unit using an inductive load.
Be sure to connect a diode in parallel with every DC inductive load that is connected to the Contact Output
Unit.
Contact Protection Circuit
Arc killers are used with the Contact Output Unit in order to prolong the life of each Relay mounted to the Con-
tact Output Unit, prevent noise, and reduce the generation of carbide and nitrate deposits. Arc killers can, how-
ever, reduce relay life if not use correctly.
Note Arc killers used with the Contact Output Unit can delay the resetting time required by each Relay
mounted to the Contact Output Unit.
Service Life with AC Load
120 VAC, resistive load
240 VAC, resistive load
240 VAC
cos = 0.4
120 VAC
cos = 0.4
0.2 0.3 0.5 0.7 1 2 3
Contact current (A)
Service Life with DC Load
300
200
100
50
30
20
10
5
100 to 120 VDC
3
= 7 to 40 ms
2
5 0.05 0.1
Max. switching frequency: 1,800 times/h
Appendix A
24 VDC = 7 ms
24 VDC, resistive load
0.2 0.3 0.5 0.7 1 2 3 5
Contact current (A)
497