High speed counter with reset
Posted 22 February 2011 - 10:52 PM
We have an application that involves an M91-2-UN2. We hope to use the HSC function reset (Hardware configuration). Digital input I2 apply the counting pulses (360 pulses per revolution) and the I3 to the reset, all square signals, taking the signal off and on the same duration. The shaft moves in one direction only.
The problem is that the reset signal ( I3 ) is not resetting the counter in less than 6 ms, but the count signal (I2) are being counted strictly accurate about 10kHz. Correct if wrong: With 60 revolutions per minute a reset and count pulse have approximately 1.4 ms. UN2 manual says the minimum pulse of HSC is 40us.
We also can not enable the SB10, and do not create any software in ladder, just configure the "hardware configuration", download to the OPLC and observe the counter MI in Debug Mode.
Posted 23 February 2011 - 04:31 PM
Input #0 and #2 can each function as either high speed counter or as part of a shaft encoder.
In each case, high-speed input specifications apply. When used as a normal digital input, normal input specifications apply.
Inputs #1 and #3 can each function as either counter reset or as a normal digital input. in either case, specificatons are those of a normal digital input.
As for SB10, it is normally on.
Posted 24 February 2011 - 01:59 AM
Posted 24 February 2011 - 11:41 AM
What exactly are you using the reset for?
Posted 28 February 2011 - 03:54 AM
I'll explain further. In this shaft which rotates in one direction to at most one rotation per second I have attached an encoder with 360 points where we use the A or B signal and the signal Z (reset).
We need to know the precise positioning at every turn. Like most PLCs have a fast reset input, we never use interruptions to reset the 360 angle. I think it would work, but I have no exactly idea how the U90 works with this interruptions in this case !!!!!
We could continue using the physical input reset, because we have speed control on the engine that drives this axis and thus "zero " the angle in super slow speed ...
Posted 28 February 2011 - 11:52 AM
Posted 02 March 2011 - 09:42 PM
Posted 06 March 2011 - 12:21 PM
I believe you will find this example helpful.
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