PLUS+1 Hardware > PLUS+1 Compliant Hardware
EMD Speed Sensor
Nilla:
Hi guys!
To get the fastest support I would recommend you to get in contact with PLUS+1 Helpdesk on plus+1helpdesk@danfoss.com.
I'm not sure where you found the info on MA-filter but I don't think that will solve Marbek's initial issue; "Our problem is the value of speed. It isn't constant. It varies over a wide range."
As I understand Marbek, although the motor that the sensor is used for keeps a constant speed, the sensor doesn't. There are no details on the accuracy or tolerance of the speed range, only that it is 0-2500 rpm. This is how the sensor works.
As the EMD sensor is managed outside our business unit, and the question is hardware related, I will try to send your feedback to their engineering department.
Best regards
Nilla
PLUS+1 Helpdesk team
Marbek_Elektronik:
Thanks Nilla.
Our customer asked helpdesk and they only send a short datasheet.
So, I asked here and I hoped to get information.
The sensor is mounted on an oil pump and the output of sensor is not constant.
We don't know how constant the oil pump is running. May be not constant over 360 degree.
But also the sensor seems to be not constant in output even if there would be a constant input speed.
If engineers give us documents of Speed over angle and other datas, this would be very interesting for us.
Now, I will test rate 50ms and 200ms and will test ma-filter 64.
If I had to programm this sensor, I would suggest a modus of the CAN transmitter to send on the same position, not on constant time intervall.
At higher speed it should send every 360 degrees 1 message for example.
At lower speed every 180 degrees, but on same positions.
The message should be the speed and then the pulses and time since last meassurement.
Ok, I am dreaming.......
G30RG3:
Hi Nilla, Marbek ...
https://assets.danfoss.com/documents/DOC152886482077/DOC152886482077.pdf Or google "L1017819 pdf"
See page 8 for info and 14 on instructions to set the parameter.
BR
G30RG3
G30RG3:
--- Quote from: Marbek_Elektronik on December 01, 2019, 03:36:40 PM ---If I had to program this sensor, I would suggest a modus of the CAN transmitter to send on the same position, not on constant time interval.
At higher speed it should send every 360 degrees 1 message for example.
At lower speed every 180 degrees, but on same positions.
The message should be the speed and then the pulses and time since last measurement.
Ok, I am dreaming.......
--- End quote ---
Wouldn't like this behavior myself, because that would mean very long intervals when the motor is close to standing still, or even no updates at all when the motor stops... OTOH at high speed you would get lots of data on the CAN-bus. The actual interval period of the MA filter should be able to filter out variations in angular velocity, but the techinfo isn't clear about the base clock on the MA filter. I expect it to be maximum 64 pulses of the encoder in its highest resolution (180 pulses per round, so about 1/3 of a round) but it could be anything.
What bothers me more: It takes about 2 rounds of the motor/sensor before there is output after a power up. So to use the sensor as a position encoder means you need to get an initialisation setting after every power up..
Marbek_Elektronik:
We use the CAN mode:
We use MA-Filter Parameter 64, because we get the best signal.
And we use Transmission Rate of 10ms.
If you use longer Transmission Rate, 200ms, the signal is not better! It's the same signal as you get if you choose 10ms and look only every 200ms to it. There is no average beause of waiting 200ms.
But, the sensor is not very good: Signal is not smothed.
For example, it is running with constant speed of 200 rpm,
the signal is : (in 0.1 rpm)
2000
2018
1990
2029
2036
2003
2026
2030
2008
2026
There are big tolerances! So it is very difficult to regulate the speed of an oil motor.
Why does speed measurement is so unexactly?
jpg: blue is the current of valve, orange is the rpm
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