A07960 — Drive: Incorrect friction characteristic

A07960 reports that the friction characteristic of the drive is incorrect. The characteristic consists of speed and torque entries held in the parameters p3820 ... p3829 (speeds) and p3830 ... p3839 (torques). While the entries violate the conditions the drive places on them, the output of the friction characteristic (r3841) is either limited to a boundary value or set to zero. The alarm value in r2124 shows which condition is affected, and the message value of the alarm names the parameter concerned.

• The friction characteristic is incorrect: the speeds and torques entered for it do not correspond to the conditions the drive expects.
• The speed entries must correspond to 0.0 < p3820 < p3821 < ... < p3829 <= p0322 or p1082, if p0322 = 0.
• The torque entries must correspond to 0 <= p3830, p3831 ... p3839 <= p0333.
• The friction torque must stay within the effective torque limits: it may be neither greater than the maximum from the upper effective torque limit (p1538) and zero, nor less than the minimum from the lower effective torque limit (p1539) and zero.

1. Read the alarm value in r2124 (interpret it as a decimal number) to determine which condition is violated.
2. Fulfill the conditions for the friction characteristic.
3. Alarm value 1538: check the upper effective torque limit (p1538), for example in the field weakening range.
4. Alarm value 1539: check the lower effective torque limit (p1539), for example in the field weakening range.
5. Alarm values 3820 ... 3839: set the parameters of the friction characteristic so that the speed and torque conditions are fulfilled.
6. If motor data (for example the maximum speed p0322) were changed during commissioning (p0010 = 1, 3), recalculate the dependent technological limits and threshold values by selecting p0340 = 5.

• The drive stores the alarm value in r2124; interpret it as a decimal number.
• 1: incorrect parameter format — this value is listed only in the S120/S150 description of the alarm.
• 1538: the friction torque is greater than the maximum from the upper effective torque limit (p1538) and zero; the output of the friction characteristic (r3841) is limited to this value.
• 1539: the friction torque is less than the minimum from the lower effective torque limit (p1539) and zero; r3841 is limited to this value.
• 3820 ... 3829: incorrect parameter number — the speed entries violate the condition given under causes; r3841 is set to zero.
• 3830 ... 3839: incorrect parameter number — the torque entries violate the condition given under causes; r3841 is set to zero.

• r2124 — alarm value: read it here, interpreted as a decimal number, to identify the violated condition.
• r3841 — CO: friction characteristic output: shows the effect directly, because it is limited or set to zero while the characteristic is incorrect.
• r3840 — friction characteristic status word: the manual refers to it in connection with this alarm.
• p3820, p3821 ... p3829 — speed entries of the friction characteristic: set them ascending and within the boundary of p0322 or p1082.
• p3830, p3831 ... p3839 — torque entries of the friction characteristic: keep them between zero and the value of p0333.
• p0322 — maximum motor speed: forms the upper boundary for the speed entries; if it is 0, p1082 applies instead.
• p1082 — maximum speed: takes over as the upper boundary for the speed entries when p0322 = 0.
• p0010 — drive commissioning parameter filter: motor data changes relevant here are made while it is set to 1 or 3.
• p0340 — automatic calculation of the motor/control parameters: select value 5 to recalculate the technological limits and threshold values.

No acknowledgement is required, and the alarm does not stop the drive. Once the friction characteristic fulfils its conditions again, A07960 goes away by itself.