Event Measurer

Measures the number of pulses (distance) between the last two events and the elapsed distance since the last event.

The count input is freely connectable from any single Encoder or FI function block Count output in any smarty on the local network.

Convenient Pulses/Rev and Scaler parameters match other positioning blocks; Linear Position and Registration promoting direct incorporation for e.g. automatic object size measurement.

Multiple instances may be used for multiple, parallel object position tracking.

Reset input sets Output and Elapsed to zero. Both outputs remain zero after Reset is made Inactive until the next event at which point Elapsed begins to count. Output remains zero until two events have occured.

Typically, transitions of Reset should not occur while the count is actively incrementing. Transitions of Reset while the count is actively changing will be associated with an uncertainty equal to the revs per second times the timebase setpoint of the containing device.

Example

The Event Measurer function block is located in a speedy with the default timebase, 5ms.

The count is from an encoder spinning at 1800RPM.

1800RPM / 60s x 0.005s = 0.15 rev uncertainty with transitions at full speed.

Other motion control function blocks with high-speed event input capability that may be useful; Registration, Event Measurer, Event Timer.

Note that aliasing errors will occur when events occur faster than the the FBE timebase setpoint, typically 5ms, 200Hz.

The function block Status is Fault and the function block output is zero if the count input is not updated for a period longer than approximately twenty times the timebase, i.e. 100ms, by default.

• Available only in the dw2xx-v2 series products
• Requires library: Precision Motion (option -39)
• Firmware versions 0x210C and later

Event

The event input is freely connectable from any single encoder marker, digital input event, or FI Event output in any smarty on the local network.

Note that aliasing errors will occur when events occur faster than the the FBE timebase setpoint, typically 5ms, 200Hz.

Count

The count input is freely connectable from any single encoder or frequency input Count output in any smarty on the local network.

Output

The measured distance between the last two events.

Elapsed

The elapsed distance since the last event.

Reset

Resets Output and Elapsed to zero. Both outputs remain zero after Reset is made Inactive until the next event at which point Elapsed begins to count. Output remains zero until two events have occured.

Status

The function block Status is Fault and the function block output is zero if the count input is not updated for a period longer than approximately twenty times the timebase, i.e. 100ms, by default.