We are having problems reading the basket speed (RPM) of a centrifuge. The speed pickup is a Hall Effect sensor as described in attached pdf. Speed gear has 72 teeth so our PCI/PULSE_VAL is set at 0.01388 and max speed is 1500 RPM. Frequency (1800hz) at max speed is well within the operating range of the probe and the CHARM DI. The DI Input (using diagnostics) did not appear to be reading until the RPM is above 500. Once there or above, it appears to read ok until the RPM drops below 500. The diagnostics show 0hz below 500 RPM. What gives?
Speed pickup for CE1701.pdf
From Books Online:
Please check if you have the HIGH_FREQ_ENA parameter enabled. If so, please disable it.
Regards,
Rune
In reply to Rune Reppenhagen:
Rune, thank you for this tid-bit! It will make a difference in our results.
The parameter meaning in DeltaV Explorer HELP is misleading. Our top speed 1500 RPM generates a probe frequency of 1.5 kHz. By interpreting the HIGH_FREQ_ENA parameter use below, this value should be set to TRUE because we are reading above 500 Hz. This is what caused or reading to drop off.
I also noticed the default FILTER time is set to 1.3 sec (1sec period of control) for a PCI discrete. Why is this? Do speed probes have a noisy signal?
In reply to putelism: