User`s manual

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(2) When an incremental type driver and encoder feedback are used
When powered ON, this module clears the present value to "0" (zero). Also, when a zero return is
performed, the position where zero return ends becomes "0". When an error (emergency stop,
etc.) occurs and the servo is turned OFF, perform zero return by the following procedure:
Clear the error.
Clear deviation.
( The present position from the encoder feedback counter is adjusted.)
Turn the servo ON.
is automatically executed internally following a deviation clear.
(3) When an absolute system-compatible driver is used
When powered ON, this module asks the driver for the present value, and matches the present
value to the absolute data from the driver. The driver is asked for the present value and the present
value is matched to the absolute data from the driver also when the absolute present value read
relay is turned ON. When the servo is turned OFF by an emergency stop, etc., perform zero return
by the following procedure:
Clear the error.
Clear deviation.
Turn the servo ON.
Read the absolute present position.
Reading of the absolute present position can be instructed by the relay at any time if
motor operation has stopped.
(4) When an absolute system-compatible driver and encoder feedback are used
When powered ON, this module asks the driver for the present value, and matches the present
value to the absolute data from the driver. When the servo is turned OFF by an emergency stop,
etc., perform zero return by the following procedure:
Clear the error.
Clear deviation.
( The present position from the encoder feedback counter is adjusted.)
Turn the servo ON.
is automatically executed internally following the deviation clear. Reading of the
absolute present position can be instructed by the relay at any time if motor operation
has stopped.
(Note 1) The instruction present position is read to read to the servo driver on an absolute system.
Reading must be performed after a deviation clear is executed with the servo OFF when
reading the value as this is the value of the instruction system counter and not the count
value of the encoder. If the instruction present position is read before a deviation clear,
the present position cannot be used as the count value of the encoder becomes an
unadjusted value.
(Note 2) Clear signal output at a zero return is an important element in determining the accuracy of
zero return. Due to this, in acceptance of the driver's clear signal, the edge of the signal is
more effective than its level on positional shift. (driver adjustment) This is because, when
the signal level is used, the deviation counter stops for 20 ms (signal output time for
positioning), encoder pulses that arrive in that time are ignored, and this causes a
proportional error.