Omron NY532-1500 Reference Manual page 481

Precautions for Correct Use Precautions for Correct Use
• This instruction is not sufficient to actually turn digital outputs ON and OFF.
• This instruction requires that you use an NX-series Encoder Input Unit and that time stamping
is operating.
Time stamping is not possible in the following cases.
• An Encoder Input Unit or Servo Drive that does not support time stamping is used.
• Object 6010 hex (Time Stamp) in the NX-series Encoder Input Unit is not assigned to a
PDO.
• The distributed clock in the EtherCAT Coupler Unit is disabled.
• An error does not occur for this instruction even if the time stamp is not updated. The ON/OFF
time will be calculated, but the result will not be the intended value.
Use this instruction only after you confirm in the MC Monitor Table or Watch Tab Page of the
Sysmac Studio that the TimeStamp member of the Axis Variable is being updated.
• If you use this instruction together with the NX_AryDOutTimeStamp instruction and with a Dig-
ital Output Unit that supports time stamp refreshing, the minimum ON/OFF range will be pro-
portional to the value of the task period and the value of the rotation rate.
For example, the minimum ON/OFF range would be 5° if one rotation of the rotary table is
360°, the rotation rate is 800 r/min, and the task period is 500 μs. The minimum ON/OFF
range would become 10° if the task period was increased to 1,000 μs.
• Set the values of the FirstOnPosition, LastOnPosition, and Duration in the switch structure
variable so that the ON/OFF range of the digital output is larger than the minimum ON/OFF
range. If it is smaller than the minimum ON/OFF range, the actual digital output may not turn
ON or OFF.
• This instruction calculates the time stamp for when the specified position is reached based on
both the current position and current velocity of the axis. The accuracy of the calculated stamp
times is influenced by the encoder resolution and the rotation rate of the axis. The error will
increase if the encoder resolution is low or the rotation rate of the axis is slow. You can calcu-
late a guideline for the maximum error with the following formula.
Maximum error in time stamp (s)
Some examples of the maximum error in time stamps for the encoder resolution and rotation
rate are given in the following table.
3,600
131,072
If the axis accelerates or decelerates quickly, the calculation error may increase. Use this
instruction when the axis is at a constant velocity.
Verify operation sufficiently to confirm safety.
• If you specify an unused axis or if the MC Test Run is in progress, Busy will change to TRUE
and InOperation and Error will change to FALSE when Enable changes to TRUE.
• Do not create two instances with the same instance name. If you do, unintentional outputs may
occur.
NY-series Motion Control Instructions Reference Manual (W561)
= 180/(Encoder resolution (pulses/rotation) × rotation rate (r/min)
Encoder resolution
(pulses/rotation)
3 Axis Command Instructions
Rotation rate (r/min)
400
800
400
800
Maximum error in calculated
time stamps (μs)
±125.0
±62.5
±3.4
±1.7
3-397
3