Hello Everyone,
I have a dilemma at the moment concerning the connection of 4 NRG #40 Wind Speed Sensors with a CR1000 datalogger. In fact, we are trying to use 4 of those sensors on a CR1000 datalogger for a project that we are supposed to wrap up pretty soon. The LLAC4 would be the best option to overcome this pulse port deficit. Unfortunately, due to time constraints and the inability for Campbell to deliver the LLAC4 in time, I could not think of a way to deal with that many speed sensors without the use of a LLAC4.
Anyone has any ideas?
Thanks.
* Last updated by: dionmanu on 6/30/2011 @ 8:19 AM *
Although strictly not recommended, for the reasons below, you can measure the AC output wind sensors using an analogue input and period measurement instruction.
The problem with this technique is the logger takes time to measure the period of a number of cycles output from the sensor, so sensors have to be measured sequentially and you cannot do this quickly.
This measurement method creates a dileamma as if specify only to measure over a very few cycles, although is quicker it can lead to apparently noisy readings. You also need to specify a timeout so the logger does not wait forever when the speed is very low or the anemometer stops. When the anemometer stops the period or frequency will read NaN, which you need to convert to zero windspeed before using the value in further processing.
Having said that we do have customers using NRG sensors in this mode as you can cram more on one logger, limited by the number of analogue channels.
* Last updated by: aps on 6/30/2011 @ 10:35 AM *