Time base problem.

[Rami]

Hello all,

i am having problems when i change the preset time for timers in Jazz.

I found a note at the web-page that you should not change the timer values when they are running, and made a bit which stops the running timers when (actually before) operator goes into the timer setting page, but this does not help. Still sometimes i got very long times after operator presses 'Enter'.

Is there any way this could be prevented?.

[Stein Yair]

Hi,

The preset value only takes effect when the timer is started. Then, the preset value is transferred to the current value register and every hundredth of a second it decreases by one until it reaches zero.

If you change the preset value after it started, the timer will continue to run according to the previous value and the new value will take effect the next time the timer is started.

However, there are advanced functions which allow you to control the timer. You can find them in the help file under Ladder > Functions > Special Functions > Store/Load Timer's Preset/current value.

[Rami]

Yes, this is how it should work, but now it seems that after the operator presses enter the timer actual value is occasionally very big time value. Even if i have set the time to MM or SS only it can take a time of hours or minutes even if the timer is only for seconds.

This Jazz is controlling wood chip boilers chip feedind system and combustion air blower. If we turn off the power shortly then it starts to count time from the correct value again, but the operator sometimes misses to turn off the power after setting the times. Now we are getting very cold weather here in Finland, so we need to tune the time values a lot until we get a balance of feed / consumption.

I have an idea of using fixed one second timer and to do the "timers" with counting these pulses until requred duration is elapsed.