ETEL DSC2P/DSC2V Servo Controller Debugging Guide

Fine phase adjustment (K52=1) is not enabled. After activation, the controller will replace the phase obtained from this initialization with K53 (the phase value pre measured by the AUT command) each time the zeroing is completed, ensuring that the electrical angle is consistent with each power on.

If using the combination mode of Home switch and Index (such as K40=34/35), it is necessary to correctly configure the polarity reversal of K58 (limit/origin switch signal source selection) and K32 (bit1 reverse Home switch, bit2 reverse encoder limit).

Parameter tuning of regulator and vibration suppression

The DSC series adopts a state space position regulator (equivalent PID)+PI current regulator. Beginners should use the "Scope" tool of ETEL Tools to iteratively optimize parameters by observing the waveforms of position (M7), velocity (M11), and current (M20/M21) through step movement.

5.1 Current loop regulation (K80/K81)

The current loop is the inner loop of the system, and its bandwidth should be much higher than that of the position loop. Automatic tuning of AUT usually provides a good initial value, but if there is current oscillation or large current tracking error, it can be manually adjusted:

K80 (Proportional Gain): Increasing K80 can accelerate current response, but if it is too high, it can cause current ripple or amplification of switch noise.

K81 (Integral Gain): Used to eliminate steady-state current errors, but excessive gain can cause overshoot or oscillation of the current loop.

5.2 Position ring adjustment (K1/K2/K4)

The position loop parameters directly affect the positioning accuracy and dynamic characteristics:

K1 (Proportional Gain): Increasing K1 can reduce tracking error, but if it is too large, it can cause overshoot. Observe the step response. If the overshoot is greater than 10%, reduce K1 or increase K2.

K2 (velocity feedback gain, equivalent derivative): Increasing K2 can suppress overshoot and oscillation, but it will reduce system stiffness. A balance needs to be struck between rigidity and stability.

K4 (Integral Gain): Used to eliminate static position errors. When K4=0, the system is purely proportional control and there is steady-state error; Gradually increase K4 until the error returns to zero, but pay attention to integral saturation (anti windup controlled by K5/K6).

5.3 Feedforward compensation (K20/K21) and filters (K8/K9)

To improve high-speed tracking accuracy, speed feedforward (K20) and acceleration feedforward (K21) can be enabled. Usually, the initial value of K20 is set to 70%~100% of K2, and K21 is set as the value related to the system inertia ratio. If the position curve appears concave or convex during acceleration and deceleration, K21 compensation can be adjusted.

For mechanical resonance (manifested as high-frequency howling from 500Hz to 1kHz), low-pass filter K8 (velocity feedback filtering) or K9 (force reference filtering) can be used. The cut-off frequency calculation formula for K8/K9 can be found in Section 13.1.2.3 of the manual. The typical starting value is 10-50, and the lower the frequency, the stronger the filtering effect but the greater the phase lag.

Synchronous startup and debugging of digital I/O and STI

The DSC controller provides digital input (DIN)/output (DOUT) for interaction with external PLCs or sensors. Especially when multiple axes need to start synchronously, using the STI command in conjunction with K160~K164 parameters can achieve the logic of "waiting for external trigger signals - starting motion simultaneously".

Typical fault: STI triggers rear axle immobility, reporting "SYNC HRO START" (M64=63).

Troubleshooting:

Check if K160 (DIN mask) and K161 (required level state) match the actual wiring. For example, if DIN1 is used as the trigger, K160=1 and K161=1 indicate waiting for the rising edge of DIN1.

Check K164 (timeout, unit STI). If the trigger signal does not arrive within the timeout period, the controller will report an error. For DSC2P/DSC2V, STI=166.67 μ s; For DSCDP/DSCDL/DSCDM, STI=500 μ s. Reasonable settings should be made based on the response time of external signals (e.g. K164=6000 corresponds to approximately 1 second).

Confirm that the controller is in "Power On" and there are no other errors (such as limit triggering).

Parameter Save (SAV) and Curing

After all parameter adjustments are completed, it is necessary to execute SAV.<axis>=2 to save the K, X, E, R, F parameters and axis numbers to Flash, otherwise the parameters will be lost after power failure. If you need to save the sequence (S register) and lookup table (L), use SAV.<axis>=0.

Attention: During the execution of the SAV command, the controller sequence execution will briefly stop, and the manual warns that the SAV command will cause the controller to perform a save operation (M64=190), which is a normal prompt message and not a fault.

On site rapid fault comparison table

Possible causes of malfunction: refer to parameters/commands for priority handling

After power on, there is no display on the LCD. The power supply is missing or the fuse is damaged. Check the main power supply and F7 fuse