Wake and Shake Function WSCNFG 0

Valid for S300, S400, S600, S700

The W&S routine consists of two parts. A rough regulation of the MPHASE value in the current mode and a fine-tuning in the velocity mode.

• Rough determination: At the beginning of the W&S current, pulses are switched to the motor with different room vectors (0°, 90°, 180°, 270°). By the resulting movement, the angle of rotor/stator position is determined.
• Fine determination: With the roughly certain phase value you change over to the velocity mode. Now a fine tuning of the angles takes place.

Commutation angle MPHASE

Relevant parameters for W&S

Temporal course of W&S

Currents which are relevant at the W&S

S300/S700

Rough determination: REFIP2
Fine determination: REFIP2 for the ID component, IPEAK for the IQ component

S400/S600

Rough determination: REFIP
Fine determination: REFIP2 for the ID component, IPEAK for the IQ component

Guide for the attitude of the W&S parameter (in special cases)

Process related limitation of the W&S function

In the previous section it is described that the angle is determined by the position change which is caused by the impressed current.
This means however, that during the W&S process a movement only occurs, that has been caused by the current impression. 
The angle will be determined with a wrong value, if an external impression causes a movement, too.

Disturbing outer excitations can be:

• powerful vibrations of the machine caused by other components
• Other axes which make a W&S at the same time
• Cross forces
• A busy axis at the W&S start
• A oscillation capable construction. The first W&S excitates the system distorts further measuring

Minimization of uncontrolled movements

Despite all security procedures there are constellations which make an uncontrolled movement of the motor possible:

• incorrect determination of the commutation angle
• incorrectly stored angle value
• incorrect orientation of the feedback
• incorrect wiring of the motor lines
• incorrect wiring of the feedback lines
• not correctly adjusted DIR value
• not correctly adjusted resolution of the feedback

We recommend two possible strategies to reduce the energy in the moved maschine parts:

Method I – F25 / F08 switch off directly

ERRCNFG 83894402 -> both a F08 ((over-speed) and a F25 (Commutation faults) switch the power stage off immediately (no speed-down ramps), also at overload / power stage fault / AS option .

reduce VCOMM e.g. to 5 -> fault F25 is recognized faster. Axis has to build up no time energy.

VOSPD adjust to smallest possible value -> (to) fast movements can cause F08 (over-speed). A dynamic adaption would be also conceivable.

Method II – F25 switch off directly / F08 ramp speed down

ERRCNFG 83894274 -> a F25 (Commutation faults) switch the power stage off immediately (no speed-down ramps), also at overload / power stage fault / AS option .
-> a F08( (over-speed) starts a fast speed-down ramping. If this is not possible, the power stage is disabled after 20% of the time EMRGTO.

EMRGTO to 1,5 x DECSTOP -> ramp in the fault case. The ramp must be chosen as short as possible but the motor still can follow with the requested current and the mechanics.
Example:
DECSTOP 200 (ms) / EMRGTO 300 (ms) !! Dimension of EMRGTO ms, DECSTOP in ACCUNIT !!.

reduce VCOMM e.g. to 5 -> fault F25 is recognized faster. Axis has to build up no time energy.

VOSPD adjust to smallest possible value -> (to) fast movements can cause F08 (over-speed). A dynamic adaption would be also conceivable.

Tip: 
Soft-Reset of faults:
DRVCNFG2 1073741824 -> F04 and F25 can be softly reset (without restart). Considerable gain in time at field bus systems.

Guarantee a stable function

To guarantee a stable function a correct parameterizing is necessary.

• A "correct" setting of the inpressing current. (See setup possibilities W&S)
• Small values are necessary for the observer at linear motors with a stiff coupling of the feedback. At the S300 an automatic tuning should be done with the command "OTUNE".
• The parameter setting of the controller must be correct. A too high gain lead to oscillation. Too small gain does not move the motor sufficiently.

Possibility for the analysis of the W&S function

• If during the W&S a commutation fault appears, then the cause of the message can be checked with the macro variable LAST25.
• With an oscilloscope image of the W&S procedure, causes like a not open holding brake, strong resonances or similar causes can be found out.

Current Velocity SEARCHKOM

Procedure

Check list

Searchkom status

1: switch to OPMODE=2
2: startingposition saved
3: roughly adjustment in OPMODE=2, Activity of WSTIME3
4: switch to OPMODE=0
5-8: smooth adjustment with x%ID of REFIP2
9: calculate MPHASE
10: back to the pre OPMODE and succesful end of W&S
20: back to the pre OPMODE and faulty end of W&S

Commutation fault F25

The commutation fault F25 is a collecting error message which can have several causes.

S400 / S600, LAST25

To be able to find the cause of this error message, the macro variable LAST25 has been introduced with firmware 5.97. This variable contains an identifier, that is refreshed at every appearance of a F25 fault. The identifier can be requested with the command "M LAST25".

These identifiers are possible:

• LAST25 = 0 W&S contouring fault supervision
  The drive did more than 1.5 mechanical "turns" during the W&S phase
• LAST25 = 1 W&S phase 1 (rough determination)
  Deflection too big: the position distance before and after the current flow is (electrically) larger than 35 degrees.
• LAST25 = 2 W&S phase 1 (rough determination)
  Deflection too small: The sum of the squares of the deflections is smaller than WSAMPL (or 65536/ENCLINES if WSAMPL = 0)
• LAST25 = 3 W&S phase 2 (fine determination)
  Iq current value too high: If the current is higher than 7.6% of DIPEAK at the end of the phase 2, then this indicates a wrong commutation angle.
• LAST25 = 4 W&S after the phase 2 (fine determination).
  The difference between the MPHASE of the phase 1 (rough determination) and the MPHASE of the Phase2 (fine determination) is larger than 30 degrees.
• LAST25 = 5 HALL faulty segment number when switching on the amplifier
  Segments 0 or 7 has been detected when reading the HALL signals. This indicates a faulty HALL cable.
• LAST25 = 6 HALL faulty segment number at the segment change
  Segments 0 or 7 has been detected when reading the HALL signals. This indicates a faulty HALL cable.
• LAST25 = freely 7
• LAST25 = 8,9 Top level supervision of the commutation fault
  This fault is aroused if the actual speed is greater than threshold VCOMM, if the ctual current is greater than ICONT and the sign of the current does not match the actual acceleration (e.g. braking action at positive speed and positive current). The supervision reprts if the described faulty situation lasts at least 12 msek

S300 / S700, ERRCODE2

To be able to find the cause of this error message, the variable ERRCODE2 has been introduced. This variable contains an identifier, that is refreshed at every appearance of a F25 fault. The identifier can be requested with the command ERRCODE2 .

• ERRCODE2 = 8 W&S contouring fault supervision.
  The drive did more than 1.5 mechanical "turns" during the W&S phase
• ERRCODE2 = 9 W&S phase 1 (rough determination) Deflection too big.
  The position distance before and after the current flow is (electrically) larger than 35 degrees.
• ERRCODE2 = 10 W&S phase 1 (rough determination) Deflection too small.
  The sum of the squares of the deflections is smaller than WSAMPL (or 65536/ENCLINES if WSAMPL = 0)
• ERRCODE2 = 11 W&S after the phase 2 (fine determination).
  The difference between the MPHASE of the phase 1 (rough determination) and the MPHASE of the Phase2 (fine determination) is larger than 30 degrees.
• ERRCODE2 = 12 W&S phase 2 (fine determination) Iq current value too high.
  f the current is higher than 7.6% of DIPEAK at the end of the phase 2, then this indicates a wrong commutation angle.

Reasons for commutation fault (F25) / VCTIM description

S300 (version: 03.08.2008)

1. During standard operation

a. Acceleration-/Deceleration phase
The commutation fault F25 occurs, if the sign of the current actual value and the sign of the the speed change do not fit to each other (8 msec long). This indicates the run-away of the motor and is stopped by an immediate block of the power stage. The commutation fault is supervised only when the current speed exceeds the adjusted threshold VCOMM. To switch the supervision off, the threshold value VCOMM must be set to the maximum possible value.

b. constant speed
The commutation fault occurs, if at a constant positive speed, the sign of the currrent actual value is negative and the value exceeds half of the max. value (for VCTIME msec). The commutation fault is only then supervised if the current speed exceeds the lowest of the two values VLIM/s and VCOMM. To switch this supervision off, the threshold value VLIM and VCOMM must be set to a higher value (if possible). With the parameter VCTIME the sensitiveness of the supervision can be adjusted. At VCTIME=0 the commutation fault is reproted immediately. In the case of an error message during the regular operation the time and/or the threshold value VCOMM should be increased.

2. During the Wake&Shake process

If a speed of more than 180 rpm is measured during the wake & shake process (determination of MPHASE at FBTYPE = 7), this indicates the run-away of the motor and leads to the block of the power stage. The fault F25 is then generated, too, if during the W&S a too low amplitude of the sine/cosine signal is measured (< 10% of nominal value)

3. With Hall sensors

(FBTYPE=11, FBTYPE=12) a fault F25 is generated, if a not valid segment number (0 or 7) has been read.