Emerson EZMotion, User Manual

Page: 118 / 268

106
EZMotion User/Programming Guide
www.controltechniques.com Revision: A8
One Shot
With this type of timer, when the Input activates, the internal clock begins to count. Once the Preset time is reached, the Output of
the timer turns ON. If the Input of the timer turns OFF before the Output turns ON, then the internal clock keeps counting and the
Output will turn on when Preset time is reached. If the Output is active and a rising edge of the Input timer is received the Output will
be reset. The Output will activate once the Preset time has past.
In the case of the One Shot type timer, once the rising-edge occurs on the Input, it does not matter what happens to the state of the
Input after that during the Preset time. When past the Preset time and the Output is still active and a rising-edge occurs on the Input
the timer will reset. The Output deactivates and will not become active until the Preset time has pasted.
Figure 112: One Shot Timer - Timing Diagram
Timer Timebase
This parameter is used to select the desired Timebase for each timer object. If you want to control the Timer using actual time
(seconds, or milliseconds, or microseconds) then the Timebase should be set to Realtime. Realtime is the default setting for the
Timebase of each Timer object. When using Realtime, the Preset value of the Timer is entered in units of seconds. For example,
after a program has run, you wish to hold an output active for ten seconds. This is an example that uses Realtime.
However, if you wanted to hold that same output active for ten revolutions of the Master Encoder instead of ten seconds, you set the
Timebase to Synchronized. This means that you are using the master encoder position to control the duration of the Timer rather
than actual Time. When the Timebase of the Timer is set to Synchronized, the Preset is entered in units of Master Distance rather
than units of Time.
Use the combo box in the Timebase column to change the individual Timer Timebase settings.
Timer Preset
This parameter is used to control the actual duration of the timer delay.
If the Timebase is set to Realtime, the user specifies the Preset value in units of seconds with resolution of 1 microsecond (0.000001
seconds). If the Timebase is set to Synchronized, the Preset value is set in units of Master Distance and the resolution is dependant
upon the Master Distance Units Decimal Places configured on the master Units view.
Once a timer has begun timing, if the Preset is modified, it is ignored until the next time the timer starts.
The Preset value must always be positive and can range from 0 to 2147483647 with the decimal place removed (example: 0.000000
to 2147.483647 with six decimal places).
Timer "Elapsed Time"
This is a read only parameter available on the Online tab that acts as feedback to the user to indicate how much of the Preset time
has expired. This value starts at zero and counts up to the Preset value.
This parameter has the same resolution as the Preset parameter.
If a Timer is Reset or Enable deactivates, this value is zeroed out automatically. Once the Preset time is reached, the Elapsed Time
will remain at its full preset value until the Timer is Reset, the Enable deactivates, or the Output deactivates.
8.5.5 Timer Signals/Events
The Timer objects has several inputs and outputs that are available on the Assignments view, or within a user program. A block
diagram of the Timer object is seen in Figure113 below.
Preset
Input
Output
Preset Preset
Active