Tuesday, June 29, 2010

Reducing electricity usage

Sarah got me one of these gadgets for Christmas and it's been a real boon. It is a clamp meter that monitors your current draw in your house's 100A feed from the street and wirelessly sends it to a monitor that lives in the kitchen. It keeps tracks of rolling averages and the best display is the one that shows instant power draw as well as a previous week's average daily consumption (in kW-hours).
Now then, at Christmas we were averaging just short of twenty kWh per day and I started on a mission to reduce this;
  • Cut the number of computers! The kitchen Mac and the Windows machine that runs MediaPortal went and a single machine (with dual DVI o/p's and dual soundcards) replaced them - it also has much better power management.
  • 'phone chargers on a timeswitch. Those wall-warts are around 50% efficient (put your hand on one even when it's not charging a 'phone).
  • All incandescent bulbs replaced with compact florescents.
  • Intelligent mains switch - this gadget powers off the TV, XBox, Wii etc when you sleep the TV. I might get a couple more for other parts of the house.
So, I've managed to reduce my consumption from 19.8kWh to 16.9kWh (as of yesterday) - that's around a tenner a month.
My next step is to replace the 50w halogens in the bathroom and kitchen with 4w LED bulbs.

Wednesday, June 16, 2010

Root6 training

I've just finished a couple of days of running four of the half-day courses I've been developing. You can get my lecture notes;

Audio 101 for runners and trainee assistants.
Video 101 for runners and trainee assistants.
QC for Television using Tektronix WFM/WVR series test set.
TCP/IP for broadcast engineers.

Monday, June 07, 2010

2010 update for Optical cabling specification for fibre‐channel SANs

Root6 has supplied many thousands of terabytes of fibre‐channel storage over the last decade and has much experience in the area of bespoke optical cabling. We are often asked to audit existing installations and the following notes are our recommendations for customers who want to provide their own cabling and not make use of our Systems Integration services.

  1. Grade of cable ‐ All current models of film and video SANs make use of multimode connection. OM3 cable is increasingly the preferred grade (50 micron laser-optimised glass as opposed to OM1 & 2’s 62.5 micron VCSEL‐optimised glass in accordance with ISO‐11801) and since current configurations are 4 gigabit (moving to 8 gigabit) more attention needs to paid to circuit loss than 1 gigabit (the standard when OM1 was introduced). Mixing OM1 and OM3 should be avoided because of the 2.5dBs of loss when going between dissimilar core sizes (62.5 vs 50 microns). In the case of an existing OM1 installation thought should be given to staying with that standard or migrating to the newer OM3.
  2. Bandwidth ‐ Whereas 1 gigabit traffic will tolerate up to 8dBs of loss we are now dealing with SANs that demand at least two octaves more bandwidth and so best practise says that we now expect no more than 3dBs of loss on a SAN circuit.
  3. Style of cable ‐ Although tight‐buffered cable is easy to install it is never optimal for long runs. For interconnection between equipment within a cabinet it is appropriate and between cabinets if run in protection – Copex etc. For inter‐area runs a loose‐tube cable is the best solution as it is an order of magnitude more robust and although has an slightly larger install‐time cost has a much lower TCO.
  4. Connectors ‐ All contemporary host‐bus adaptors and fibre‐switches terminate runs in the LC connector. If existing cables are terminated in legacy SC or ST connectors they should either be re‐terminated or re‐run as adaptors introduce signal loss. SC or ST patch panels are fine so long as run‐out cables are SC‐LC (to equipment) as appropriate.
  5. Testing – We will ascertain if circuits are suitable for proposed SAN deployment by illuminating them with a calibrated laser tester (850nM wavelength, ‐19dB(m) signal) and measuring circuit loss – these results will be provided to the customer.

Friday, June 04, 2010

Requirements for Electrical Supply for Systems Integration projects

If we are obliged to power equipment sited in a machine room and/or edit suites we ask that the customer’s project manager and electrician read and sign these notes to ensure a proper configuration for the mains supply. The difference between an optimal arrangement of mains power and one that merely satisfies the requirements of safety legislation will be the difference between a smooth-running facility and one that is bedeviled by hum on signals and corrupt data streams. Attention to detail initially will save money and result in a robust system.
  1. Circuit breakers - Our requirement is that the customer’s electrician provides a separate spur connection for each bay and all feeds are provided via a D-rated 16A MCB. We recommend the area is protected by an Earth Leakage Breaker. For the edit rooms an MCB-protected 16A mains feed terminated in a Commando connector is required. Since most equipment used in modern television production represents inductive loads C-rates breakers found in domestic and office premises will results in unnecessary supply interruptions.
  2. It is important that the customer’s electrician runs the earths for the edit rooms back to the same earth bus-bar as the mains feeds to the bays thus creating a technical supply for all production/editing equipment.
  3. The practice of tying the domestic ‘cooking’ earth to the technical earth should be avoided as a quick and cheap way of unifying the earths between the edit suites and machine room. Although this satisfies the requirement of a safety-earth it means that the technical earth is now united with the dirty earth.
  4. Be aware that new projects that start after June 2008 have to conform to 17th Edition of the IEE regs (BS7671:2008). These notes are meant as additions to legal requirements and should be included in Root6’s Scope Of Works submission.
  5. Testing- we will regard demarcation of responsibility for the machine room cabinets and edit suite desks as being at the 16A Commando connector – we will provide a standard set of tests results (earth continuity, Insulation, run-current, leakage, and flash-test) from that point for every circuit. We ask that the electrical contractor provided us with a copy of his test results as detailed in IEE.17th.ed and Part-P.