Heidenhain encoders can acquire data from production machines and plants to carry out the diagnostics of their status. This enables digital networking at a higher level. We focus on rotary encoders for the acquisition of motor data.
by Elena Magistretti
The digital networking of machines has become an important factor for productive and flexible production. Equally important, however, is the exchange of information within a machine. Only if the individual components interact effectively in the overall system can the machine develop its range of services.
Modern machines and systems are able to monitor themselves. They know their stages of wear, and they can even optimize themselves during operation. The prerequisite is the exchange of information between drives, sensors and the control.
Heidenhain encoders have been supporting extensive internal machine communication for many years and, with system monitoring, offer other important functions for acquiring, monitoring and providing motor information.
The acquisition of motor data
Rotary encoders from Heidenhain, featuring high control quality and system accuracy, have many practical functions that make drives even more efficient and safer. One of these functions deals with temperature control. If temperature values in the motor are measured by sensors, Heidenhain encoders can transmit these values to the inverter via the EnDat interface. By comparing them with a temperature model of the motor, the inverter can then adjust the control behavior. Also, with the help of the temperature values, an excessive load on the bearing or wear can be detected in good time.
Inductive encoders from Heidenhain can also ascertain the gap between the graduation carrier and the scanning unit and thus the distance from the shaft to the motor stator. This makes it possible to detect changes, e.g. due to high force acting on the motor shaft during operation.
Forward-looking system monitoring and data analysis
Changes in the engine can have a negative effect on the machining result or on the motor itself. It is therefore particularly important to detect these changes in good time. The permanent evaluation of the temperature values and the scale-to reticle gap enables the early detection of malfunctions, excessive load, or wear. This enables you to react before damage occurs or the production availability is impaired. Heidenhain encoders also contain specific warning messages and categorized error messages that are output via the interface. The control can act accordingly and execute predetermined error reactions.
To evaluate the encoder functions, evaluation numbers can be read cyclically from the encoder during normal operation. The valuation numbers show the current condition of the encoder and provide information on the functional reserve. For encoders without integral bearings, it is also possible to use the valuation numbers to assess the assembly quality.
Heidenhain inspection and testing devices make easy commissioning and extremely comprehensive diagnostics of the encoders possible. In addition, these data enable you to document the shipping status of the motor and save it in the company database.
Encoders from Heidenhain have a fixed and a freely definable memory area. Specific encoder data, but also motor data, e.g. the electronic ID label of the motor, can thus be stored in the encoder. These data simplify the commissioning of the motor and can even automate it. In addition, the operating data of the motor shortly before a fault can be saved in the encoder memory. The evaluation of speed, temperature, angular acceleration and current values provides important analysis information on the cause of a fault.
Data transfer and Functional Safety
The EnDat interface from Heidenhain is a digital, bidirectional interface for encoders. Position values are output via the EnDat interface while information is read out, updated or stored. The data are transmitted in synchronism with the CLOCK signal from the subsequent electronics. Heidenhain offers encoders that can be used in safety-related applications. These encoders operate as single-encoder systems with purely serial data transmission via EnDat 2.2. Reliable transmission of the position is based on two independently generated absolute position values and on error messages that are provided to the safe control. For the encoder analysis Heidenhain offers the appropriate PWT testing units and PWM inspection units. The PWT testers offer a variety of basic functions that enable easy diagnostics and commissioning. The PWM inspection units can be used universally. They have smaller measuring tolerances and can be calibrated.