F33115 — Encoder 3: Amplitude error track A or B (A^2 + B^2)

F33115 reports that the amplitude of the two signals of Encoder 3 — the root of A^2 + B^2 — has left its permissible window. The nominal signal level of the encoder must lie between 375 mV and 600 mV (500 mV -25/+20 %); for Sensor Modules for resolvers (e.g. SMC10) the nominal level is 2900 mV (2.0 Vrms).

The manuals describe the same code under two titles and slightly different limits: on G130/G150 it is raised as "Encoder 3: Amplitude error track A or B (A^2 + B^2)" when the amplitude leaves the tolerance band in either direction, while on S120/S150 it is raised as "Encoder 3: Signal level track A or B too low" only when the level falls below the response threshold. Depending on the drive configuration, the same condition can also be output as an alarm (A) or with no reaction (N).

• On G130/G150, the amplitude (root of A^2 + B^2) of encoder 3 exceeds the permissible tolerance: it falls below 170 mV (observe the frequency response of the encoder) or rises above 750 mV. For resolver Sensor Modules such as the SMC10, the limits are below 1070 mV and above 3582 mV.
• On S120/S150, the signal level (root of A^2 + B^2) of the encoder falls below the permissible limit value: below 170 mV when the input frequency is 256 kHz or less, and below 120 mV when the input frequency is above 256 kHz. For resolver Sensor Modules such as the SMC10, the threshold is below 1070 mV.

1. Check that the encoder cables and shielding are routed in compliance with EMC.
2. Check the plug connections.
3. Replace the encoder or encoder cable.
4. Check the Sensor Module (e.g. contacts).
5. For measuring systems without their own bearing system: adjust the scanning head and check the bearing system of the measuring wheel.
6. For measuring systems with their own bearing system: ensure that the encoder housing is not subject to any axial force.

• The drive stores the measured levels in r0949, to be interpreted as hexadecimal yyyyxxxx: xxxx is the signal level of track A and yyyy the signal level of track B, each 16 bits with sign.
• The message value is output as "A track: %1, B-track: %2", i.e. the two decoded signal levels.
• For orientation: a signal level of 500 mV peak value corresponds to the numerical value 5333 hex = 21299 dec; a signal level of 2900 mV peak value (resolver Sensor Module, e.g. SMC10) corresponds to 6666 hex = 26214 dec.
• The analog values of the amplitude error are not measured at the same time with the hardware fault output by the Sensor Module.

• r0949 — fault value of this message: read it as hexadecimal yyyyxxxx to see the measured signal levels of track A (xxxx) and track B (yyyy) and compare them with the nominal 500 mV (5333 hex) or 2900 mV (6666 hex) level.

Remove the cause first. The drive executes OFF1, and the acknowledgment is only accepted while the pulses are inhibited: bring the drive to pulse inhibit, acknowledge the fault, then restart the drive. Where the condition is configured as an alarm (A) or without reaction (N), neither a reaction nor an acknowledgment applies.