I am trying to check Endress Huaser ultrasonic level sensor FDU 83 with transmitter FMU867. I connected in my workshop. Changed the most important parameters like full and empty calibration type of material being measured. My problem is that I am not getting reading. I can not see any signal/noise ratio. The transmitter as well as the sensor are new.

What should I do?

 

First, put the device back to its default parameters. You may well have set something incorrectly.

Second, aim the sensor at a target (the wall, a large piece of wood, metal, etc.) and let the signal stabilize. You should be able to read the distance from the sensor to the target. Then move either the sensor toward the target or the target toward the sensor. You should get readings that track the change in distance. Then you can put the level parameters in, and you should see level instead of distance.

If you have setup your transmitter and sensor the way I suggest, and you have no signal, or the distance to the target is erroneous, something is wrong. Call Endress+Hauser tech support for help.

Walt

Walt Boyes, FInstMC, Chartered Measurement and Control Technologist
Life Fellow, International Society of Automation
Editor in Chief, Control and ControlGlobal.com
[email protected]

 

Thanks

I tried almost the same way, but in some cases it works. But again when i check the same sensor with same transmitter next time, it does not work. No echo at all. The transmitter gives give fault code 261 or 261 which says the internal temperature sensor faulty, although it is new sensor.

Even when it works the response is very slow. Now i am confused whether the transmitter is having problem or the sensor itself is malfunctioning. OR both are ok but we are missing something. As you told, I reset the parameter to factory default and set three main things, empty/full and type of material used and unit of measurement. but ...as described up ,it is not working.

 

It definitely needs to go back to the factory, it sounds like to me.

Walt Boyes, FInstMC, Chartered Measurement and Control Technologist
Life Fellow, International Society of Automation
Editor in Chief, Control and ControlGlobal.com
[email protected]

 

Once again thanks

I managed to find out the problem but don't know why exactly does this instrument is behaving like this. Terminal number 63 and 64, which I don't have Idea what for these terminal are. But When i removed the wires from 63, 64 the instrument started working OK. I can see that at 63&64 written "syn.FMU"

any idea?

 

Google is your friend.
The manual is your friend.

Page 16, FMU manual 45564377:

Synchronisation line

In order to avoid cross-talk between parallel routed sensor lines connect the transmitters max. 20) to a synchronisation line. The sensors are then scanned in sequence. If more devices are present, groups of 20 transmiters should be used. The cables within one group can be in parallel. The cables of different groups must be separated. Common screened cable can be used.

The synch line is for synchronizing the pulsing of multiple (more than one) level transmitters in close proximity to avoid crosstalk.

 

I believe this is required in the sensors fixed in same tank or bin for getting average or difference in level. In such case if both sensor work together it may affect each other. Right?

What about if there are many bins and each has its individual sensor? This syn. is required or can be neglected ?

 

Synch is for
- transducers installed in the same tank/bin or

- when the cables from the electronics box to the transducers run in parallel even when transducers are in separate tank/bin

 

thanks guys

I read some other documents of the manufacturer and came to know that by when all the transmitters are connected in syn., all the transmitter send pulse to sensors simultaneously and wait until all get the feedback from the sensors. In such case if one of the sensor or transmitter is not working, the rest will also not work. Am I correct or not?

 

I'm not sure which document you were reading, but other ultrasonic vendors do not do it in that fashion.

> The sensors are then scanned in sequence.

I would interpret that statement as multiple transducers are not fired simultaneously, but in sequence, one after another. Since the same transducer is used for firing its energy and then listening for the return echo, sequential firing would presumably allow sufficient elapsed time between firings so the last fired transducer can fire, ring down and 'listen' for its returning echo, without having adjacent or nearby transducers producing 'false' echoes during its listening period.

I would not expect one failed transducer to affect others, but I'm not Mr. Endress or Mr. Hauser.