Speed Encoder Of The Spindle - HEIDENHAIN iTNC 530 HSCI Technical Manual

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6.12.2 Speed encoder of the spindle

Digital speed control requires a shaft speed encoder:

Define the speed encoder input in MP113.x. MP121.x is used to assign the

outputs to the spindles with the CC 61xx controllers.

The iTNC 530 monitors the reference mark of the speed encoder. The monitor

checks whether the line count for one revolution from reference mark to

reference mark is equal to the line-count entry in the motor table.

If differences occur, the DSP error message C3A0 Incorrect reference

position S appears. If this happens, check the speed encoder, encoder cable,

and whether you have selected the correct motor.

With a gear wheel encoder, even if it is properly installed, monitoring can

result in this error message due to its inherent inaccuracy:

In this case, switch the monitoring off with MP2220 bit 0 = 1.

The iTNC 530 monitors the direction of rotation. If the nominal value of current

exceeds the limit value for a certain time, the DSP error message C380 Motor

<spindle 1/2, axis> not controllable appears.

In MP113.0 and MP 113.1 you can set different inputs for the speed encoder

of the spindle, even if the PWM output for the spindle drive stays the same.

The PWM output and the two encoder inputs must be on the same drive-

control motherboard (DSP) of a CC, however. This means that they must be

configured on CC connectors with the same letter A or B.

This may be necessary for applications in which you switch between two

spindles or spindle motors that are operated with the same UM power

At lower speeds, high-frequency spindles only have a low amount of torque.

If such a spindle is having its speed controlled, the tool changer may slightly

twist the spindle, causing the limit of current to be exceeded. This leads to the

above error message:

In this case, switch the monitoring off with MP2221 bit 1 = 1.

For axes, monitoring of the rotational direction (MP2220 bit 1) must not be

deactivated. An error (e.g. one motor phase interchanged with another or

incorrect entry in the DIR column of the motor table) might cause

uncontrolled acceleration of the motor in one direction if the monitoring

function for the rotational direction is deactivated.

This also applies to spindles. For spindles, however, an incorrect

acceleration in one direction is less dangerous than for axes.

Monitoring of the direction of rotation (MP2220 bit 1) for synchronous

motors (entry SM in the column TYPE in the motor table) cannot be switched

HEIDENHAIN Technical Manual iTNC 530 HSCI