AuxiliaryEmulatedQuadratureDivider Parameter
Default Value: 1.0
Minimum Value: 1.0
Maximum Value: 65536.0
Units: None
Type: float
HARDWARE: This parameter applies only to the iXR3 or XR3 that uses the -CT4 encoder multiplier option.
IMPORTANT: When you use the encoder multiplier, your drive adds a fixed latency of 800 nanoseconds when the Auxiliary Feedback connector is configured as PSO Distance input or PSO Window input.
The AuxiliaryEmulatedQuadratureDivider parameter decreases the effective resolution of emulated quadrature signals that the drive generates from the auxiliary encoder multiplier feedback module.
The default value of the AuxiliaryEmulatedQuadratureDivider is 1. Change this parameter from the default value only when the system resolution and speed of motion cause the maximum encoder frequency of the axis to be greater than the maximum quadrature output frequency of the drive. The maximum quadrature output frequency of all Automation1 drives is 100 MHz (counts per second). You can use the Drive Encoder Output feature to send the emulated quadrature signals from the drive. The maximum frequency of the Drive Encoder Output is 25 MHz. To calculate the maximum encoder frequency of the axis based on the features you want to use, use the equation that follows:
If you are using the Drive Encoder Output feature to send the emulated quadrature signals from the drive:
- If the maximum encoder frequency is less than or equal to 25 MHz, use the default value of 1.
- If the maximum encoder frequency is greater than 25 MHz, change the parameter from the default value.
If you are not using the Drive Encoder Output feature to send the emulated quadrature signals from the drive:
- If the maximum encoder frequency is less than or equal to 100 MHz, use the default value of 1.
- If the maximum encoder frequency is greater than 100 MHz, change the parameter from the default value.
Changing the AuxiliaryEmulatedQuadratureDivider from the default value:
The non-default value does not change the resolution of the servo loop.
The quadrature multiplication factor is equal to the value of the AuxiliaryEncoderMultiplicationFactor parameter divided by the value of the AuxiliaryEmulatedQuadratureDivider parameter. See to the equation that follows.
The quadrature multiplication factor must obey the conditions that follow:
- It must be an integer to get a whole number of quadrature pulses per encoder cycle. If it is not an integer, the controller rounds the result to the nearest integer and a small difference occurs between the expected quadrature resolution and the actual quadrature resolution.
- The value of the integer must be greater than 4. If it is not greater than 4, the drive will not generate emulated quadrature signals.
- The value of the integer must be greater than the minimum frequency divider. Use this equation to calculate the minimum frequency divider.
IMPORTANT: The AuxiliaryEmulatedQuadratureDivider parameter decreases the effective resolution of the quadrature signals that are used for PSO tracking. If you set this parameter to a non-default value, divide your PSO firing distances by the value that you set for this parameter. For example, if you set the AuxiliaryEmulatedQuadratureDivider to a value of 2, you must divide all PSO firing distances by a factor of 2.
Jitter Specifications
When you use the encoder multiplier, the drive may generate emulated quadrature signals that are not exactly the same as the encoder position. When the drive samples a sine wave encoder and generates emulated quadrature signals, it can only give an integer number of counts per encoder sample, up to the maximum quadrature encoder output frequency (100 MHz). This can cause jitter between counts of generated emulated quadrature signals. The table that follows specifies the jitter at different encoder input frequencies.
Table: Jitter Specifications
| Input Frequency (counts/second) | Jitter |
|---|---|
| < 10 MHz | +/- 100 nanoseconds |
| 10 to 20 MHz | +/- 25 nanoseconds |
| 20 to 30 MHz | +/- 8.33 nanoseconds |
| 30 to 40 MHz | +/- 4.17 nanoseconds |
| 40 to 50 MHz | +/- 2.5 nanoseconds |
| 50 to 60 MHz | +/- 1.67 nanoseconds |
| 60 to 70 MHz | +/- 1.19 nanoseconds |
| 70 to 80 MHz | +/- 0.89 nanoseconds |
| 80 to 90 MHz | +/- 0.69 nanoseconds |
| 90 to 100 MHz | +/- 0.55 nanoseconds |
