reklaw

Yeah, but if there is only one timer, there would only be one source. Cmp instructions compare source a to source b. I wouldn't have a source b, correct? @ BobLFoot --I would post the sample logic but this is all on paper. The lab is the only place I have access to any kind of simulator. I was using RSLogix to practice on my home PC but it was only for a limited trial period.

Hello! I am new to the forum here and thought I would join because it seems like a great place for PLC info. I am just beginning to design really basic PLC logic and had a n00b question. I was wondering if it were possible to use one timer with two or more time periods with an Allen Bradely PLC. Ex. When input A is turned on, a light will be on for 10 seconds. After that it will be off for 2 seconds and then again on for 5 seconds. After this, the light will not turn off again until input A is turned off. I know how to do this easily with more than one timer but it is supposed to be done using one timer only. But the AB plc only allows a timer (TON) with a single preset value as far as I know. Maybe this can only be done using something like a S7 or GE Fanuc, Modicon etc...? Any insight??? Thanks in advance for you time.