SIEMENS SINUMERIK 840C 611-D Startup and Troubleshooting Guide

2. Motor selection and data calculation

For Siemens motors, parameters can be automatically loaded from the built-in motor data sheet through the "Select Motor" function. For non Siemens motors, SW5 and above versions provide a convenient starting method:

Select 'Non Siemens motor' and fill in the nameplate data (rated power, rated current, rated speed, etc.).

The system will automatically calculate the equivalent circuit diagram data from the nameplate data.

Next, through the "Calculate Controller Data" function, the system will automatically calculate the gain and integration time of the current controller and speed controller, as well as the torque and power limits, greatly simplifying the integration work of non-standard motors.

3. Measurement and optimization of drive control circuit

The system provides measurement functions for current, speed, and position control circuits for precise optimization.

Frequency response measurement: By injecting noise signals and evaluating the Bode plot, mechanical resonance points can be accurately identified. This enables engineers to set the current or speed setpoint filter (low-pass or band stop) in the 611D driver in a targeted manner, thereby suppressing resonance and improving control stability.

Step response measurement: By observing the actual value following the step change of the speed or position setting value, the proportional gain (P) and integration time (I) of the speed controller can be optimized, and the KV coefficient of the position loop can be adjusted.

Data backup and CPU replacement strategy

Data is the soul of numerical control systems. SINUMERIK 840C provides multiple data backup mechanisms to prevent production interruptions caused by hardware failures.

1. Valitek tape drive/PC link backup

The system supports data backup through VALITEK tape drive (connected to MMC-CPU parallel port) or PC link (connected to external PC through dedicated parallel port cable). In the "Diagnosis ->Startup ->Backup" menu, engineers can choose:

Backup system: Fully backup all software (operating system, user programs, options) on the hard drive.

Backup user data: Only backup all data under the user branch.

Restore system/user data: Backfeed previously backed up data to MMC-CPU.

2. Restart process after MMC CPU replacement

After replacing the MMC CPU, the following steps must be performed to restore the system:

Use a tape drive or PC link to restore the entire system or user data.

If the hardware configuration of the new CPU is different from the original system, it may be necessary to reconfigure the WOP options or display parameters through the "Setup/Configure options" in the ACKUP menu.

In SW6 and above versions, if the buffer battery of the NCK CPU is replaced or a software update is performed, the S-RAM area of the NCK will be automatically cleared. The system will display alarm 10 ("Start after software update") and enter startup mode during the next startup, at which point a complete startup process must be executed.

3. Loading phase of NCK user data

When the system is powered on, the data loading of NCK is divided into three key stages:

Stage 1: Boot the system program. Triggered when NCK detects system program loss or system error in DRAM.

Stage 2: Load user data. The system will request and load user UMS (User Memory Structure), IKA (Interpolation and Compensation) data records, etc. Note that TEA1, TEA2, TEA3 (axis/spindle drive data) will not be loaded at this stage.

Stage 3: Load data from the standard workpiece program.

Advanced diagnosis and special function applications

1. Contour monitoring and quadrant error compensation

Contour monitoring: The system detects collisions or driving faults by comparing actual tracking errors with model-based calculated tracking errors. Engineers can set tolerance zones (NC MD 332) and response threshold speeds (NC MD 336) to avoid false alarms due to small fluctuations.

Quadrant Error Compensation (QEC): Used to compensate for contour errors caused by friction and clearance when the axis exceeds the imaging limit. SW4 introduces the neural network QEC, which can automatically calculate and optimize the compensation characteristic curve through a "learning phase" without the need for manual complex parameter settings. Users only need to pass the circular test, and the system will automatically complete the optimization.

2. Processing of absolute value encoder

For shafts equipped with SIPOS or ENDAT absolute encoders, the relevant machine data settings are crucial:

MD 1808 *, bit 0: Indicates that the axis is equipped with an absolute value encoder.

MD 1808 *, bit 3: Indicates that the absolute value offset in MD 396 * is valid. This offset is used to synchronize the absolute value system of the encoder with the absolute coordinate system of the machine tool. If the value is 1, the system will automatically recognize it as "reference point reached" after power on.

MD 1808 *, bit 6 (single turn absolute value encoder): For a rotating shaft, if you want to use the absolute position information of the encoder within one turn and ignore the possible overflow of the number of turns, you need to set this bit.