Time delay relays will begin their timing cycle either upon “power up”, or by having a separate input wire to begin the timing cycle sometimes known as Input Voltage, Signal, or Start in the datasheet timing diagrams. The timing diagrams in each datasheet will have to be checked out as they will vary between models and device settings.
Viewing this input waveform is crucial and will help you determine if you need a retriggerable device, if the input can remain on, be a pulse, or be able to turn off before the timing function is either activated or completed. Further information may have to be obtained from the circuit driving the time delay relay, such as frequency or switch functions (N.O./N.C.).
Take a look at below ON-Delay example, both are not retriggerable:
H3CR-A/-AS/-AP*/-A-301 (11 pin versions)
This model only requires a start pulse to initiate the ON-Delay, timer begins from the first upward pulse and is not retriggerable until timing cycle completes:
H3CR-A8/-A8S/-A8-301 (basically the same but 8 pin versions)
This model requires a continuous voltage to initiate the ON-Delay, timer begins when voltage is applied and will operate until voltage is removed:
See pages 13-15/61 below for full timing charts and retriggerable diagrams within this series:
https://assets.omron.com/m/541b101861257edf/original/H3CR-A-F-G-H-Datasheet.pdf
See pages 20-24/44 for H5CX series timing diagrams:
http://www.ia.omron.com/data_pdf/cat/h5cx-_-n_l111-e1_5_6_csm2122.pdf
See also:
Time Delay Relay Functions
Summary
H3CR-A AC100-240/DC100-125
H3CR-A8-302 DC24
H3CR-AS AC24-48/DC12-48
H3CR-A AC24-48/DC12-48
H3CR-A8 AC100-240/DC100-125
H3CR-A8E AC/DC24-48
H3CR-A-301 AC100-240/DC100-125
H3CR-AP AC100-240/DC100-125
H3CR-A8-301 AC24-48/DC12-48
H3CR-A8E AC100-240/DC100-125
H3CR-AP AC24-48/DC12-48
H3CR-A8 AC24-48/DC12-48
H3CR-A8-301 AC100-240/DC100125
H3CR-A-300 AC24-48/DC12-48
H3CR-A-301 AC24-48/DC12-48
H3CRA8AC100240DC100125Q1
H3CR-A8S AC24-48/DC12-48
H3CRAAC2448DC1248Q1
H3CRA8EAC100240DC100125Q1
H3CRA8AC2448DC1248Q1
H3CR-A-300 AC100-240/DC100-125
H3CRA8EACDC2448Q1
H3CRAAC100240DC100125Q1
OSA-A3
H5CX-A11D-N DC12-24/AC24
H5CX-L8-N AC100-240
H5CX-A11S-N AC100-240
H5CX-L8E-N AC100-240
H5CX-ASD-N-DC12-24/AC24
H5CX-L8D-N DC12-24/AC24
H5CX-A11-N AC100-240
H5CX-AD-N AC24/DC12-24
H5CX-A-N AC100-240
H5CX-AS-N AC100-240
H5CX-A11SD-N DC12-24/AC24
H5CX-L8SD-N DC12-24/AC24
H5CX-L8SD AC24/DC12-24
H5CX-AD AC24/DC12-24
H5CX-A11 AC100-240
H5CX-L8S-N AC100-240
H5CX-BWSD-N DC12-24
H5CX-L8D AC24/DC12-24Q
H5CX-A AC100-240
H5CX-ASD AC24/DC12-24
H5CX-AS-AC100-240
H5CX-L8ED-N DC12-24/AC24
H5CX-L8 AC100-240
H5CX-BWSD
H5CX-A11D AC24/DC12-24