How to proceed if, when operating TTL / HTL encoders on the SMC30,
the messages 3n100 and/or3n101 (n stands for encoder 1 or 2) are
displayed resp. the higher-level controller is deactivated with
These messages may be caused by the following:
1) The encoder evaluation input frequency was exceeded or
2) The zero pulse signal is too short in time.
SMC30 comprises a zero mark monitor counting the number of encoder
pulses between two zero marks. If the encoder frequency exceeds 300
kHz, encoder pulses may get lost or the zero mark can no longer be
identified. In this case, the drive sets the fault bit 15 in the
encoder status word Gn_ZSW, which is displayed in SINAMICS
parameter r0481[n-1]. The SINAMICS messages 3n100 and/or 3n101 are
The SINUMERIK responses to the fault bit with fault 25000.
This problem can be solved by switching over to encoderless mode.
For this, set the drive machine data ENCODERLESS MODE CHANGEOVER
SPEED Servo-p1404 to a speed supplying reliable signals. Further,
the drive machine data CURRENT CONTROL AND MOTOR MODEL
CONFIGURATION must be set to Servo-p1402.2=1.
Set the axis machine data ENCODER LIMIT FREQUENCY MD36300 in the
axis machine data.
A SIMODRIVE position encoder with 5000 pulses/rev has been attached
as direct measuring system to an axis (6FX2001-2CF00). That means,
the critical encoder pulse frequency of 300kHz is reached at 3600
rpm. With a certain safety margin, the SINAMICS shall be operated
without encoder as from 3000 rpm:
p1404 = 3000 rpm
Park the encoder as soon as the drive is operated without
p1402.2 = 1
On the SINUMERIK, the encoder limit frequency value may not
MD36300 <= 0.95 * (p1404 * p0408) / 60 = 237500 Hz
The number of encoder pulses is stored in SINAMICS parameter
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