Hold the TIMER

Dear all,

If I want to make hold for current value of timer by switch and when I make switch on the program will read the end value of current value and start from this value
I use Siemens S7-300

Allen-Bradley has a tool called RTO (Retentive Timer ON) which does exactly that.

Check this out:
http://www.plctalk.net/qanda/showthread.php?t=8757&highlight=s7+timer

Or search here and the web for "RTO in S7"

S7 Pauseable timer

Please find attached my implementation of a pauseable S7 timer.
It consists of three parts:

1. A front end FC212 (the interface to your program)
2. An interrupt driven (OB35) data handler
3. A DB with data structures
4. An example is given in OB1

Some rules:

1. Timer is in 0.1s increments
2. Timer value cannot be larger than preset
3. Preset range is from 0..65535 (over 6500s)
4. Output is active if preset is larger than value
5. Reset input has priority over run input
6. Run input must be active for timer to increment

Maybe it has useability for someone.

Best regards,
tonus.

P.S.
The source is available in a zip but is just too large for this forum to accept.