Emerson Control Techniques FM-4 Reference Manual page 95

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.
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 Figure 76 below.
Input Events
TimerEnable
TimerInput
TimerReset
Figure 74: Timer Object Block Diagram
Input Events / Destinations
The following signals are available in user programs and as Destinations on the Assignments view.
Timer.#.TimerEnable
The Timer Enable event is level sensitive (not edge only) and is used to enable the Timer object. If a timer is not Enabled,
the Output will never activate regardless of the state of the Input.
Timer.#
Preset
Type
Timebase Elapsed Time
Setting Up Parameters
Output Events
TimerActive
TimerOutput
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