DT9857E Data Loss

[GSAS - Karthick]

Hi,

One of my customers will use DT9857E with 64 expandable channels connected across 52 sensors through BNC cables. 

They will be capturing data from vibration sensors across 25 railway compartments. 

1. Will there be any loss of data because of the length of the cable?

2. The maximum sampling size of the module, will it change when it's expanded to 64 channels.

3. If the sampling rate varies, what is the max sampling rate for individual channel when it is expanded to 64 channels?

[Fausto]

Hello @GSAS - Karthick.

All analog input channels of the four DT9857E devices can be synchronized using the Sync Bus. Note that the RJ45 cables connecting the Sync Bus on each device must be less than 1 foot in length.  Therefore, all four devices should be at the middle point between compartments.

All cable lengths between all four DT9857E devices to their connected sensors should be the same length.

All channels will acquire data simultaneously at the set sampling rate.

What is the application's sampling rate requirement?

Given the number of analog input channels and high sampling rate capability, a new robust Windows system (i.e. latest processor, high RAM, minimum background processes running, USB 3.x) and a custom application developed with the Open Layers API is recommended.  The maximum achievable sampling rate is dependent on the ability of the host system to process the data.

What are the sensors to be used?  Please provide their datasheets.

 

Regards,

Fausto

[GSAS - Karthick]

Hello Fausto,

I will get the sensor datasheet shortly.

If the cable lengths are of the same length, can we guarantee there won't be any loss of data? 

 

[Fausto]

Hello @GSAS - Karthick.

Thank you.  The A/D channels will acquire synchronously based on the sync bus connection, but there is no guarantee of any loss of data based on the unique application described.  Please elaborate more on the customer's concern.

Regards,

Fausto

[GSAS - Karthick]

Hello Fausto,

They are using 52 Single Axis Accelerometers in 25 Railway Coaches to measure the Vibration Data from the Train Coaches.  

They will be using a maximum of two sensors per train, they want to connect all the sensors to the DAQ either at the end of the coach or at the center of it. 

This way is preferred because it is easier to connect with a UI.

The maximum sampling rate for their application is 100K.

[GSAS - Karthick]

Hello Fausto,

Any update on the above?

[Fausto]

Hello @GSAS - Karthick.

The customer's proposed application is unique and we cannot guarantee any data loss.  Field testing would be required to determine data integrity.  Also, please share the sensor's datasheet.  Is a sampling rate of 100 kHz a requirement?

Regards,

Fausto