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8 Pulse Output Units
NX-series Position Interface Units User’s Manual (W524)
8-10 Functions
8
8-10-8 Interpolation Control for Missing Synchronization Command
The Pulse Output Unit outputs pulses in sync with the command position that is received each fixed
period.
If synchronized communications falls out of sync or if the cycle is broken for any other reason and a
command is lost, the command position for that period is not updated.
In this case, the Unit will receive the same command position as before, which will result in a travel dis-
tance of 0 or in an immediate stop (velocity 0).
Therefore, refreshing synchronized commands is monitored to prevent the machine from stopping
abruptly or to prevent the stepper motor from step loss.
If the command position cannot be obtained at the expected time, the command position is predicted
based on the previous two command positions so that operation continues.
If the number of consecutive missing synchronization commands exceeds the value that is set
for the Number of Synchronization Command Interpolations parameter, an Incorrect Synchroni-
zation Command error occurs.
When the Output Mode Selection parameter is set to velocity-continuous pulse output, interpolation is
performed as follows when a synchronous command is missing:
• Command position: Command position is presumed based on the previous two commands (primary
interpolation)
• Command velocity: The previous command velocity is retained.
If a normal command is received so that the value set for the Number of Synchronization Command
Interpolations parameter is not exceeded and the Unit recovers from the interpolation control state, the
return operation for that command is performed with position-synchronous pulse output.
8-10-8 Interpolation Control for Missing Synchronization Command
Parameter name Setting Default Remarks
Number of Synchroni-
zation Command
Interpolations
0 to 16 (interpolations) 2 • This parameter sets the maximum num-
ber of interpolations for missing synchro-
nization commands.
• Set this parameter to 0 to disable the
function.
• Changes are applied when the power
supply to the NX Unit is turned ON or the
NX Unit is restarted.
Interpolation for Velocity-continuous Pulse Output
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