PrimarySsiEncoderSetup Parameter
Default Value: 0
Minimum Value: None
Maximum Value: None
Units: None
Type: int
HARDWARE: This parameter applies only to the drives and configurations that follow:
Table: Applicable Drive Types and Feedback Options
| Drive Type | Feedback Option |
|---|---|
| FLEX | Using an SSI absolute encoder |
| SI4 | Using an SSI absolute encoder with the -A1 absolute encoder option |
| iXA4 | Using an SSI absolute encoder |
| XA4 | Using an SSI absolute encoder |
| iXC2 | Using an SSI absolute encoder |
| XC2 | Using an SSI absolute encoder |
| iXC2e | Using an SSI absolute encoder |
| XC2e | Using an SSI absolute encoder |
| iXC4 | Using an SSI absolute encoder |
| XC4 | Using an SSI absolute encoder |
| iXC4e | Using an SSI absolute encoder |
| XC4e | Using an SSI absolute encoder |
| iXC6e | Using an SSI absolute encoder |
| XC6e | Using an SSI absolute encoder |
| iXI4 | Using |
| XI4 | Using |
| iXL2e | Using an SSI absolute encoder |
| XL2e | Using an SSI absolute encoder |
| iXL5e | Using an SSI absolute encoder |
| XL5e | Using an SSI absolute encoder |
| iXR3 | Using an SSI absolute encoder |
| XR3 | Using an SSI absolute encoder |
WARNING: The drive cannot detect if an SSI encoder becomes disconnected from the Absolute Encoder Clock or Data pin on the feedback connector. Use the Encoder Fault feature in the FaultSetup Parameter so that the drive can detect when the feedback connector is disconnected. The user is responsible for safely wiring the system.
Use the PrimarySsiEncoderSetup parameter to configure options related to the SSI encoder interface of the drive. The sections that follow give the possible settings for this parameter.
Initial Position
This option specifies how the drive initializes the position feedback of an axis when you use an SSI absolute encoder for feedback.
Always Positive is the default. When the drive initializes the position of an axis, it interprets the value from the encoder as an unsigned number. Thus, the initial position is always positive. For example if you set the
When you select Positive or Negative, the drive interprets the value from the encoder as a signed number when it initializes the position of the axis. Thus, the initial position can be positive or negative. For example, if you set the
Use Parity
This option specifies the SSI encoder frame to either receive or not receive a parity bit.
No Parity Bit is the default. When you use this setting, the drive does not try to receive a parity bit.
When you select Use Parity Bit, the drive calculates the odd parity of the position word that it receives from the encoder. The drive compares the odd parity against the parity bit that follows the last bit of the position word that the drive receives. If a parity error occurs during this calculation, the drive generates a feedback fault.
Timeout Behavior
This option specifies the drive to either generate or not generate a feedback fault if the condition that follows occurs - The drive does not receive the SSI encoder word within the period of time that is necessary to supply a new feedback sample for each execution of the servo loop. The period of time that is necessary to sample an SSI encoder can be very different between encoder manufacturers. To calculate the period of time that is necessary to sample an SSI encoder and determine if that period of time is sufficient for the execution of the servo loop, use the equation that follows:
The drive uses a 500 kHz (2 us period) serial clock to sample the SSI encoder.
Fault On Encoder Timeout is the default. When you use this setting, the drive generates a feedback fault if it cannot sample the SSI encoder within the period of time that is necessary for the execution of the servo loop.
When you select Do Not Fault On Encoder Timeout, the drive does not generate a feedback fault if it cannot sample the SSI encoder within the period of time that is necessary for the execution of the servo loop.
