Function Blocks
RTMR Resettable Timer Function Block
330 HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07
RTMR Resettable Timer Function Block
Description
The RTMR label stands for Resettable Timer.
This block is part of the
Counters/Timers category.
Function
The Resettable Timer block has the following attributes:
• Provides increasing or decreasing timing base on an enable input.
• Increasing time from 0 or preload value.
• Decreasing time from preset or preload value.
• Increasing time provides digital output upon reaching Preset
• Decreasing time provides digital output upon reaching zero
• Reset input sets increasing timer to zero.
• Reset input sets decreasing timer to preset value.
• Preset value may be internal, or remote via a dedicated input
• Inc./Dec. selection is via digital input.
• Toggling the reset (RST) pin resets the current elapsed time and loads the new preset value; therefore,
if changing the preset value (remote or local), the user must enter the new preset value, then reset the
timer for the new preset to be used during the next time cycle. If the timer is reset prior to entering the
new preset value, the timer will use its previous preset for its compare condition.
Inputs
RST
= Off to On transition, Reset. Toggling RST resets the current elapsed time and loads the new preset
value; therefore, if changing the preset value (remote or local), the user must enter the new preset value,
then reset the timer for the new preset to be used during the next time cycle. If the timer is reset prior to
entering the new preset value, the timer will use its previous preset for its compare condition.
EN = ENABLE ON = run; timer is counting
OFF = Timer is stopped; output (TIMER) held at last value
TIM_DN = ON (time down); OFF (time up)
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