Specify the Required Analog Averaging and Sampling Rate
Analog Averaging and Analog Sampling Rate fields are displayed on the SCADAPack x70 tab of I/O Modules that support these options.
- Analog Averaging—Use this combo box to specify whether samples of analog input values are collected and averaged. Averaging is equivalent to low-pass filtering and is intended to reduce noise on analog input channels. Choose from:
- None—No sample values are collected or averaged.
- 2 Samples—This option calculates the average value of the current sample and previous sample. The current sample value is then replaced with the calculated average value.
This option provides the fastest averaging, but allows more noise to pass through the analog input channel than the other sampling options.
Noise suppression starts at 8 Hz when the Analog Sampling Rate is set to 'Fast'. If the Analog Sampling Rate is set to '50/60Hz Filter', the input filter values will increase approximately 10-fold.
- 3 Samples—The default. This option calculates the average value of the current sample, previous sample, and the next sample. The current sample value is then replaced with the calculated average value.
This option provides the middle level of averaging and noise reduction compared to the other sampling options.
Noise suppression starts at 5 Hz when the Analog Sampling Rate is set to 'Fast'. If the Analog Sampling Rate is set to '50/60Hz Filter', the input filter values will increase approximately 10-fold.
- 8 Samples—This option calculates the average value of 8 samples starting from the current sample. The fourth sample is then replaced with the calculated average value.
This option provides the highest level of smoothing and noise suppression, but the calculation takes longer to perform than the other sampling options.
Noise suppression starts at 3 Hz when the Analog Sampling Rate is set to 'Fast'. If the Analog Sampling Rate is set to '50/60Hz Filter', the input filter values will increase approximately 10-fold.
- Analog Sampling Rate—Use in conjunction with the Analog Averaging property to specify the rate at which analog input values are sampled. Choose from:
- Fast—Select this option to calculate samples at the fastest possible rate, but not provide any noise filtering at 50/60 Hz.
- 50/60Hz Filter—The default. Select this option to filter noise at 50/60 Hz, while sampling values at a rate that is slower than the fastest possible sampling rate. Such noise filtering might be required when equipment such as power supplies that generate noise in this frequency range are nearby.