Sensor change for RS1D v8

Technical Support
1

Hi everyone,
this is my first post on the forum.
I just switched on my RS1D at home to perform some tests, it seems to work perfectly out of the box :slight_smile:

I plan to use the RS1D for a structural monitoring application, which requires the use of an horizontal geophone instead of the vertical one.

The current vertical geophone in the RS1D seems to be a 4.5 Hz 395 Ohm vertical Racotech RGI-20DX, electronically extended down to 1Hz as described in the spec sheet.

I guess that I must find an horizontal sensor with the same caracteristics (eigenfrequency, resistor, no damping shunt, same sensitivity of 23.4V/(m/s)?
Would you recommend any brand? (maybe sticking with Racotech would be a good idea?)

I also have three minor questions which come as a following:

-> is there a simple way to rename the channel from EHZ.D (actual code for vertical channel) to EHN.D or EHE.D (once the horizontal sensor will be setup), for example?
(I can do it afterwards using obspy in /opt/data/archive/ otherwise)

-> would it be possible to use geophones with lower eigenfrequencies (e.g. 1Hz) and higher sensitivities (e.g. 80V/(m/s) or 200V/(m/s)) in order to get clearer ambient noise measurements?
I think it will interfere with the electronic correction and sensitivities, so that the waveform may be distorded? And the instrument response will not be accurate anymore.

-> Using the RS3D, is it possible to replace the Z sensor by a third horizontal sensor?
I plan to use 3 geophones each in a landcase, installed on 3 different structures and connected to the RS3D with a few meter-long cable for each.

Thank you for your help,
and for designed such a tool!

Best regards

Pierre

2

Hello Pierre, welcome to the community!

This is a very interesting project! I’ll start by saying that yes, a RS3D could be the best solution for you.

Regarding the geophone sensor that you could use for horizontal detection, you can find it our recommendations here: DIY Options for your Raspberry Shake Seismograph Earth Monitor remembering also that there is no problem switching the vertical with a horizontal geophone

Unfortunately, it is not possible to rename the channels, because they are set according to the standard naming convention. As you stated, you can do it afterwards, if needed.

It is not possible to use the geophones with different eigenfrequencies, and also, naturally, the instrument response will no longer be valid for any geophone that is not provided by us.

It is instead possible to replace the vertical with another horizontal sensor, always remembering to rename or recall which channel the new sensor is transmitting on.

To conclude, it is not possible to have the geophones/sensors so far away from the Shake. The maximum distance is 20cm. If the cables are longer than that, they start acting like antennas, picking up more and more interferences.

I hope that I was able to clarify your doubts on the matter.