What instruction is used to change the value on a on delay timer so that the operator can change the value on the time delay without rewriting the ladder program.
If you are using AB 5000, with an HMI Ethernet I believe you have to open the factory talk view and assign an address to change the particular value trough the HMI
I forgot to mentioned in a PLC 500 AB used the MOV instruction then destination to a specific register N7:XXX OR directly into the timer delay you may have to use the BCD converter. This is done assuming u have the operator panel inputs linked to the PLC