Providing the absolute machine encoder position over a standardized protocol

This section describes the machine capability to provide the absolute encoder position data.

Overview

Absolute encoders are capable of providing unique position values from the moment they are switched on. The output of an absolute encoder indicates the current shaft position, making it an angle transducer.

Machines running on a HIL device can send encoder data to external devices using EnDat, BiSS or SSI standardized protocols.

Basic, absolute single turn encoder is implemented.

Position data is 16bit value.

Encoder resolution is defined by the Encoder ppr property on the machine dialog window (Figure 1).

Figure 1. Encoder resolution definition

Protocol limitations

Implemented protocol limitations are:
  • EnDat:
    • Only the Encoder send position values command is supported (code 000111). This EnDat 2.1 command is compatible with EnDat2.2
    • Position values are sampled with interrupted clock
    • No CRC
  • BiSS:
    • Only point-to-point configuration is supported
    • Only Single Cycle Data (SCD) is supported
    • Right-aligned
    • No CRC
  • SSI:
    • Only point-to-point configuration is supported
    • No CRC

Digital Input configuration

Clock and/or data signals from an external device should be connected to the desired digital input pin on the HIL device. Additional, these pins need to be defined in the machine dialog window. On the Feedback tab (Figure 2) values for clock and/or data pins need to be defined. The connected signal can be active high, or active low, depending on the user’s external device.

Figure 2. Machine feedback tab

Digital Output configuration

Data from the HIL device (EnDat data, EnDat gate, BiSS data and SSI data) can be set to any digital output. Digital outputs are defined in the Digital Outputs window in SCADA (Figure 3).

Figure 3. Digital Outputs section
Note: Absolute encoder protocol is not supported on HIL402 (configurations: 1, 2, 3, and 4).