Micro Input Module sample rate ?

[MikeBarker]

Can the VideoBox Lite ( using a RLVDLMICIN01 Micro Input Module ) log analogue data from, say, four strain gauges at 50Hz ?

How is the module connected to the VideoBox - RS232 or CAN ? What is the fastest scan / sample rate possible for each of the four inputs, and for the RPM input ?

[Lucie]

Can the VideoBox Lite ( using a RLVDLMICIN01 Micro Input Module ) log analogue data from, say, four strain gauges at 50Hz ?

How is the module connected to the VideoBox - RS232 or CAN ? What is the fastest scan / sample rate possible for each of the four inputs, and for the RPM input ?

Hi,
The Video VBOX Lite logs data at 10Hz, so will not be able to capture any inputs at 50Hz:(

The Micro Input Module is connected to the VVB via CAN. The only log rate which any data (GPS or MICIN) is captured at is 10Hz.

Hope this is helpful :thumbsup: :thumbsup:

[MikeBarker]

Lucie,

Thanks - what equipment do you have that will work at 50 Hz ?



Hi,
The Video VBOX Lite logs data at 10Hz, so will not be able to capture any inputs at 50Hz:(

The Micro Input Module is connected to the VVB via CAN. The only log rate which any data (GPS or MICIN) is captured at is 10Hz.

Hope this is helpful :thumbsup: :thumbsup:

[Lucie]

Lucie,

Thanks - what equipment do you have that will work at 50 Hz ?

We make dataloggers which log at rates of 5Hz, 10Hz, 20Hz and 100Hz.:thumbsup:

If you wanted to log data from a Mini or Micro Input Module at 50Hz, you would have to use a 100Hz logger and change the log rate to 50Hz.
--The Micro and Mini input modules work up to 100Hz when connected to the correct logger.

The only datalogger that would work at this rate is a VBOX3i.:rolleyes:

We also make speed sensors which output at 100Hz but these cannot log data.

What is your application? What tests are you doing? If you explain what you are doing we may be able to advise you which equipment would suit your application best....:D :D

[MikeBarker]

The idea is to measure the performance of human powered vehicles as used in various sports.

Typically they will travel at 0 - 25 km/hr, have a cadence of 0 - 45 beats per minute. We wish to measure speed ( 10 Hz GPS is fine ) but acceleration and a few analogue inputs will need to be at about 50 Hz. Can you break out the 3 axis acceeromenter data into 3 seperate raw data streams in the datalogger ?

I will doublecheck to see if 10 Hz for acceleration and analogue inputs are OK. 20 Hz may work.

It is also critical that there is low latency – we will want to match the all the sensor data to the 25 fps vide with good accuracy. Any idea what the latencies could be ?

We also need a seprate GPS timestamp to the nearest millisecond so we can sync with other GPS Cams.

We are most impressed with your GPS ! Good stuff.

[Darran]

The Video VBOX products are all designed to synchronise to the GPS data very accurately. Each sample of data written to the VBO file is stamped with the time index into the video which is corrected for latency within the Video VBOX. Any additional latency will be external to the system, such as CAN bus, etc. On a VVB sourcing data from a Micro Input Module on a dedicated bus, this should not be an issue (there's nothing else on there to contest the bus and cause arbitration and retransmission that might increase latency). In addition to this timestamp, the log file includes a UTC channel which provides the UTC time taken from GPS, which is very accurate indeed.

Neither the Video VBOX, nor the Micro Input Module have built in accelerometers. The acceleration reported by the Video VBOX is calculated from GPS as we have speed accurate to 0.1km/h and heading accurate to 0.1°. You could wire up an accelerometer to analogue inputs on the MICIN or use an accelerometer with CAN outputs such as our own Inertial Measurement Unit (IMU).

Given your desire for higher accuracy and video synchronisation, you may wish to take a look at the Video VBOX Pro (http://www.videovbox.co.uk/index.php/en/component/content/article/34/48-video-vbox.html) which is available in a 20Hz variant.

[MikeBarker]

Darran, Lucie,

Thanks for your prompt and knowledgeable replies. Do you mind if we take this offline to avoid boring the Group with all the trivial detail :)

My email is info@mikebarker.co.za