N31415 — Encoder 1: Amplitude alarm track A or B (A^2 + B^2)

N31415 reports that the signal level of encoder 1 — the amplitude formed from tracks A and B as the root of A^2 + B^2 — is outside the permissible tolerance. The manuals print the message as Signal level track A or B outside tolerance (alarm) and as Amplitude alarm track A or B (A^2 + B^2); the condition behind both titles is the same. The nominal signal level of the encoder must lie in the range 375 mV to 600 mV (500 mV -25/+20 %); the drive responds below a threshold of 230 mV, and the frequency response of the encoder must be observed. On Sensor Modules for resolvers, for example the SMC10, the nominal signal level is 2900 mV (2.0 Vrms) and the response threshold is below 1414 mV (1.0 Vrms). Depending on the drive configuration, the same condition can also be issued as a fault (F) or an alarm (A); the message version itself triggers no drive reaction. The manual notes that the analog values of the amplitude error are not measured at the same time with the hardware fault output by the Sensor Module.

• The signal level of encoder 1 — the root of A^2 + B^2 from tracks A and B — is outside the permissible tolerance.

1. Check the speed range: the frequency characteristic (amplitude characteristic) of the measuring equipment may not be sufficient for the speed range in question.
2. Check that the encoder cables and their shielding are routed in compliance with EMC.
3. Check the plug connections.
4. Replace the encoder or the encoder cable.
5. Check the Sensor Module, for example its contacts.
6. If the coding disk is soiled or the lighting has aged, replace the encoder.

• The drive puts the amplitude in %1 and the angle in %2 of the message value; the same information is held in r2124.
• Interpret r2124 hexadecimal as yyyyxxxx: yyyy is the angle, xxxx is the amplitude, i.e. the root of A^2 + B^2 (16 bits without sign).
• The angle 0 ... FFFF hex corresponds to 0 ... 360 degrees of the fine position; zero degrees is present at the negative zero crossover of track B.
• For encoders, a signal level of 500 mV peak value corresponds to the numerical value 10650 dec.
• For resolver Sensor Modules such as the SMC10, a signal level of 2900 mV peak value corresponds to 3333 hex = 13107 dec.

• r2124 — alarm value: read the amplitude and the angle of this message here and split the hexadecimal value as yyyyxxxx (xxxx = amplitude, yyyy = angle).
• p0491 — motor encoder fault response (ENCODER): the manual's note for this message points to this parameter, which sets the drive's response when the signal-level condition is present as a fault.

The message and the alarm require no acknowledgment: the entry clears itself as soon as the signal level of encoder 1 is back inside the tolerance. If the drive raises the condition as a fault, the response executed is the motor encoder fault response set in p0491; the fault is acknowledged immediately, with no waiting time, after which the drive can be restarted.