# Sinumerik Alarm 300749 Axis %1 drive %2 conversion factor between motor and load too large

Sinumerik Alarm 300749 Axis %1 drive %2 conversion factor between motor and load too large

Parameters:
%1 = NC axis number
%2 = Drive number

Definitions:
The conversion factor from the motor system [increments] to the load system [µm/mdeg] is larger than 1 or the factor which converts the load system to the motor system is larger than 65535. Conditions: The condition for the factor load system to motor system is: µm_to_incr <= 65535 The condition for the factor motor system to load system is: incr_to_µm <= 1 with µm_to_incr = 1 / incr_to_µm Formula for rotary axis: The following applies for rotary motor encoder and rotary axis: incr_to_µm(n) = (MD1321 SAFE_ ENC_ GEAR_ DENOM(n) / (MD1322 SAFE_ ENC_ NUMERA(n)) * incr_to_µm_rot_rotax with n = 0 ... 7 (gear stage) and incr_to_µm_rot_rotax = (360000 / 8192) * (1 / MD1318 SAFE_ENC_RESOL)• MD 1318 SAFE_ENC_RESOL (number of encoder lines per revolution)• MD 1321 SAFE_ENC_GEAR_DENOM[n] (encoder/load gear denominator)• MD 1322 SAFE_ENC_GEAR_NUMERA[n] (encoder/load gear numerator) Formula for linear axis: The following applies for rotary motor encoder and linear axis: incr_to_µm(n) = (MD1321 SAFE_ ENC_ GEAR_ DENOM(n) / (MD1322 SAFE_ ENC_ NUMERA(n)) * incr_to_µm_rot_lin incr_to_µm_rot_lin = (1000 / 8192) * (1 / MD1318 SAFE_ENC_RESOL) * MD1320 SAFE_ENC_GEAR_PITCH Explanations: • MD 1318 SAFE_ENC_RESOL (number of encoder lines per revolution) • MD 1320 SAFE_ENC_GEAR_PITCH (spindle pitch) • MD 1321 SAFE_ENC_GEAR_DENOM[n] (encoder/load gear denominator) • MD 1322 SAFE_ENC_GEAR_NUMERA[n] (encoder/load gear numerator) • n = 0 ... 7 (gear stage) Request: During boot-up of the control.Reactions:
– Mode group not ready.
– Channel not ready.
– NC Start disable in this channel.
– NC Stop on alarm.
– Alarm display.
– Interface signals are set.

Remedy:
Please inform the authorized personnel/service department. Check the following safety- relevant MDs depending on the motor encoder type and axis type and correct, if necessary.
• MD 1317 SAFE_ENC_GRID_POINT_DIST Grid division linear scale (for linear encoder)
• MD 1318 SAFE_ENC_RESOL Encoder marks per revolution (for rotary encoder)
• MD 1318 SAFE_ENC_RESOL
• MD 1320 SAFE_ENC_GEAR_PITCH (for rotary encoder and linear axis)
• MD 1321 SAFE_ENC_GEAR_DENOM
• MD 1322 SAFE_ENC_GEAR_NUMERA (when using a gear)
• The motor encoder type and the axis type are determined via MD 1302: \$MD_SAFE_IS_ROT_AX.

Program Continuation:
Switch control OFF – ON.

#### References

1. Siemens Diagnostics Guide by Siemens
Sinumerik Alarm 300749 Axis %1 drive %2 conversion factor between motor and load too large