Wednesday, March 19, 2014

Blackmagic VideoHub software and QLogic fibre cards under MS Windows

Here's something from the dim recesses of my brain that I'd just remembered. Blackmagic VideoHub routers take all their network traffic over port 9990; which is also used in some QLogic/SAN configurations for metadata traffic. They don't play nice with each other. 
To fix this set the BM Software (whilst USB-connected to the hub) to use another port. Then you'll have to set all the client copies to use whatever number you chose. The default won't do!

Tuesday, March 18, 2014

Next update on the Oscilliscope Watch

I got the email saying that mine has been shipped! Also - a Post Office depot card was awaiting me at home yesterday; as soon as I can get to the collection office...!

 Please keep in mind that there is a lot to do and the little that has been implemented has lots of bugs.

Oscilloscope Watch Overview

Firmware upgrading

One common task you will need to perform is to update the firmware, this is done thru the USB port and using the FLIP application from Atmel. To enter bootloader mode, you need to press the KL and KI buttons for a few seconds. You will hear a distinctive sound to indicate that the device is in bootloader mode, and the red LED will stay lit once connected to the computer, the LCD will be blank. The Oscilloscope Watch will appear as a new device on the host computer, the drivers required are found in the FLIP application folder.

The procedure to upgrade the firmware:
  1. Start Flip.
  2. Select ATXMEGA256A3U in the device selection list.
  3. Select USB as communication medium.
  4. Open the USB port to connect to the target.
  5. Make sure the FLASH buffer is selected and check: ERASE, BLANK CHECK, PROGRAM, VERIFY.
  6. Load the HEX file Xprotokey.hex.
  7. Press RUN.
  9. Load the HEX file Xprotokey.eep.
  10. Uncheck ERASE and BLANK CHECK, only leave checked PROGRAM and VERIFY
  11. Press RUN.

The latest HEX files will be stored in Github.
I am planning to incorporate the firmware upgrading to the XScopes Software, so all these steps will be replaced with a single button press.

Firmware development

I hope to be releasing new firmware updates every one or two weeks. Any Beta backer that wants to participate in the development of the firmware is welcome. You can send me a message with your Github ID if you want to stay in sync and share your contributions.
To develop on the Oscilloscope Watch you will need to download Atmel Studio. The source code for the Oscilloscope Watch is available on Github.
If the device hangs, one method to reset the device is to press the KL and KI buttons for a few seconds. This will make the device enter bootloader mode, then press KM and KD to reset the device.

Wednesday, March 12, 2014

Bryant's network control/measuring PDUs

My good pal Simon Quill at Bryant has been developing this line of intelligent bay mains distribution for the last few years and I bought a couple last year and have (due to the weight of work) only just got around to playing with them. Quite a lot of manufacturers offer remotely controllable power strips with either a bit of client software or a web interface to control the various circuits. Some even offer current monitoring (typically via a shunt-resistor so you get apparent current; the heating effect, in effect!) but Bryant claims to actually measure the current via a clamp-inductor and they calibrate each circuit's 16-bit ADC prior to it leaving the factory. Simon tells me each circuit can measure to 50A to an accuracy of 1mA and they sample at 1Khz so you can see any harmonic content that is being put on by UPSes etc. 

Some of the other features;
  1. Macro start-up, close sequence. You can (for example) get o/p 2 to hold off powering up until o/p 1 has settled.
  2. Control of each circuit via the web interface - re-power that server?
  3. Inspect the current draw (and power factory) on a per circuit basis; worried that an array of disks is starting to show odd consumption; maybe a drive is about to fail?
  4. Look at the quality of the incoming mains - it's rarely a sine wave nowadays!
Simon & I intend to do an episode of The Engineer's Bench on IP controlled PDUs (not just these Bryant ones) but until then here are some screen-grabs.

 This one shows the graph for the third circuit which has an AlicePak audio balancing interface attached and is (we hope!) a linear supply and hence should be an entirely resistive load.
 This is my trusty Tektronix WFM7120 which is clearly using a switch-mode supply; notice how the current draw is when the driver transistor switches as the voltage passes a set value.
 This one shows the earth leakage current against incoming mains; a bit more sine-like but remember the effect is made worse by the presence of the Tek & the AlicePak.
This is a circuit which has no load and so consequently we're seeing the auto-ranged current draw which is just the quantised noise of the ADC.


Thursday, March 06, 2014

Real live pictures via Antrica - over the Internet

Although it's a shaky iPhone video this is the Antrica system streaming over the public Internet between Root6 West (where the Dev team live) and the main Root6 offices in Wardour Mews. So - it's going via different bandwidth providers (so not just to Sohonet's local pop or anything); presumably all the way to the London Internet Exchange in Docklands. I limited the stream to 4 Mbit/sec and it went all afternoon without so much as a dropped frame. Compression artifacts are rare and minor.
Here is a screen grab from VLC (which can also be used as a viewer).