User`s manual

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9
Allowable deviation during operation ±500
Allowable deviation at end of operation ±500
Deviation 0
[3] Mode 2
This mode is for performing positional compensation according to the feedback data.
Compensation is performed so that deviation is eliminated after the positioning instruction pulse is
output. When output of all instruction pulses is completed and then positioning does not fall within
the completion pulse allowable range within the positioning monitoring time, the completion range
error (017) is output and operation is stopped. When positioning does not fall within the closed loop
control allowable range during operation, the closed loop control allowable range over error (error
015) is output and operation is stopped.
• Set the ratio between the number of instruction pulses and number of feedback pulses from the
encoder in parameters in advance.
When this mode is used in stepping operations, it provides a function for correcting the position to
the intended position even if the stepping motor gets out of sync. In this case, make the following
two settings for distinguishing the extent of this out-of-sync (correctable or a fatal shift).
Set the number of pulses for judging end of positioning. (completion pulse allowable range)
Set the pulses for judging stepping motor out-of-sync. (closed loop control allowable range)
If a load is applied on one of the vertical axes, for example, when the servo is used, the servo
deviation that cannot be tracked is compensated. In the case of a servo, deviation is judged on the
driver side, so set the closed loop control allowable range to "0". When this range is set to "0", only
the allowable range at completion is monitored in this mode.
Example of connection with servo driver
In the following example, let us assume the following conditions:
• operation up to position 5000 by direct operation
• a completion pulse allowable value of 5
• a closed loop control allowable range of 0
(The deviation range during operation is monitored on the driver side.)
A completion range error (017) is output if the information from the encoder was 506 after the JW-
12PS started up and output 5000 pulses, and after the positioning monitoring time. During
operation, the position is compensated at all times, however, this error is output when, for example,
positioning does not fall within the completion range at completion due to a mechanical load.
• In this mode, the closed loop control allowable range is set to "0" and judgment during operation
is not performed.
(Note) The compensation time set at parameter 2 - 0001 is the area to which the compensation
speed when deviation is present is set.
"Compensation speed" refers to execution of compensation at the speed of one pulse per
compensation time when there is a deviation of one pulse. For example, the compensation
speed becomes 10 pulses (20 pps) per 500 ms when the compensation time is 500 ms at
deviation 10 pulses. If the deviation decreases by the compensation pulse, the speed of the
compensation pulse also falls correspondingly and the compensation speed reaches 0 at
deviation 0 to absorb deviation.
• Positioning does not fall within the allowable deviation in the monitoring time and an error does
not occur even if the deviation at completion of operation is not "0".
Example of connection with stepping motor (driver)
In the following example, let us assume the following conditions:
• operation up to position 5000 by direct operation
• a completion pulse allowable value of 5
• a closed loop control allowable range of 500
A completion range error (017) is output if the information from the encoder was 5006 after the JW-
12PS started up and output 5000 pulses, and after the positioning monitoring time. A closed loop
control allowable range over error (015) is output and operation is stopped if the deviation (error
between instruction value and feedback value) is monitored during positioning and the feedback
value was 5501 (deviation 501).
During operation, constantly monitor the deviation, and adjust the pulse so that deviation is
eliminated at all times.