Mitsubishi Electric MELSEC iQ-R RD78G4 User Manual page 61

When "2: Used in incremental system" is set in the servo parameter "Scale measurement function selection (PA22.3)", "0" is
set for the initial value of the synchronous encoder axis position value and the synchronous encoder axis position value per
cycle after the servo amplifier axis is connected. Therefore, connection becomes valid, and the counter is enabled.
If the corresponding servo amplifier axis is not connected, the connection of the synchronous encoder axis will be invalid.
Precautions
• When "1: Used in absolute position detection system" is set in the servo parameter "Scale measurement function selection
(PA22.3)" and the movement amount after the synchronous encoder axis unit conversion (synchronous encoder axis units)
against the synchronous encoder movement amount (encoder pulse units) while the servo amplifier is disconnected or the
power supply is OFF exceeds "2147483647" or "-2147483648", the synchronous encoder axis position value is restored
with its opposite sign.
• If other than 0 is set to the servo parameter "Load-side encoder resolution setting (PE51)" while the A/B/Z-phase differential
output type rotary encoder is used, the following may occur.
- Since the Scale cycle counter (Obj. 2D36H) changes suddenly when passing through the first Z-phase, the synchronous
encoder axis position value and the synchronous encoder axis position value per cycle also change suddenly.
- If the incorrect encoder resolution is set to the servo parameter "Load-side encoder resolution setting (PE51)", the value of
the Scale cycle counter (Obj. 2D36H) becomes incorrect, and therefore the synchronous encoder axis position value and
the synchronous encoder axis position value per cycle may change suddenly.
■Point of the setting method
• When the servo parameters "Scale measurement function selection (PA22.3)" and "Load-side encoder resolution setting
(PE51)" are changed, it is required to switch the power of servo amplifier off once after the parameter is transferred to the
servo amplifier, and then switch it on again.
• If the servo amplifier set by the servo parameter "Scale measurement mode selection (PA22.3)" does not support the
"Scale measurement mode", "AL.37" (parameter error) will occur in the servo amplifier. Refer to the servo amplifier
instruction manual for details of the servo parameter "Scale measurement mode selection (PA22.3)".
• The following information of the synchronous encoder via servo amplifier can be output with the optional data monitor. The
setting details of the optional data monitor for the synchronous encoder information are shown below.
Information of synchronous
encoder
Scale position within one-revolution
Scale absolute counter
• A scale measurement encoder can be used in an incremental system by setting "2: Used in incremental system" in the
servo parameter "Scale measurement function selection (PA22.3)" even when using a scale measurement encoder that
supports the absolute position detection.
■Restrictions
• The scale measurement function can only be used when semi closed control mode is selected. Refer to the servo amplifier
manual for details.
• When "1: Used in absolute position detection system" is set in the servo parameter "Scale measurement function selection
(PA22.3)", "AL.25.2 (Scale measurement encoder - Absolute position erased)" occurs in the relevant servo amplifier after
the encoder cable is connected and the power supply is turned ON for the first time. Wait for five seconds with the alarm
occurring, and then turn on the servo amplifier power again to clear it.
• "Synchronous encoder via servo amplifier invalid error" (Error code: 1DFAH) occurs in the following cases.
• When "[Pr.141] IP address" of an unset axis or a virtual servo amplifier axis is selected as the axis No. for "Synchronous encoder via servo amplifier" in
"[Pr.320] Synchronous encoder axis type".
• When a servo amplifier axis not having the servo parameter "Scale measurement function selection (PA22.3)" enabled is set as the connection servo
amplifier axis No. in "Synchronous encoder via servo amplifier" and connected to the servo amplifier.
• When the axis No. selected as the "Synchronous encoder via servo amplifier" in "[Pr.320] Synchronous encoder axis type" has a servo amplifier other than
the MR-J5-_G_, MR-J5-_G_-RJ, or MR-J5D_-_G_ connected.
• A linear scale is connected. [Add-on SimpleMotion version "Ver.1.30" or earlier]
• A linear encoder (absolute position type) is connected. [Add-on SimpleMotion version "Ver.1.31" or later]
Setting detail for optional data monitor
H2B12: Load side encoder information 1 (Used point: 2words)
H2B13: Load side encoder information 2 (Used point: 2words)
2 INPUT AXIS MODULE
2.3 Synchronous Encoder Axis
2
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