90-70 timer

How do I change a timer in my 90-70?

Since you were just asking about a password for the Series 90-70, I'm going to assume that you're using the programming software to go about changing the timer, and that when you say 'change a timer', you mean that you want to change the timer's preset value.

Timers in the 90-70 can have either a constant or a register value for their preset. If the original programmer used a constant as the preset, then you need to modify the program to change the constant. If the preset is a register value, then you need to write a new value to the register.

When you're running the programming software, connected to the PLC, and the software tells you that you are in a "Logic Equal" state, move the cursor to the left of the timer block where it shows either "CONST" or "%Rxxxx" where xxxx is a number. If the preset is a constant (CONST), type in a new value and download the change to the PLC. If the preset is a a register address, follow the software's procedure for writing a new value. The exact procedure varies depending on which software package you're using. If you need help with the exact sequence of keystrokes or mouse clicks, let me know which package you have.