First and foremost: you should know what you're doing, use your head. The values to be computed with this tool are as accurate as possible, but please allow not only for programmer's faults, but also for oxydized contacts, loose screws (have you recently checked your cables, eh?) etc.

Purpose of this tool is to calculate voltage drop, resulting power drawn, and max. number of frames per PSU for a given G-Lec installation.

Handling is as easy as possible:

(1) input the data of your installation (frame type, cable lengths)

(2) read the maximum number of frames possible with the cables given

(3) let the programm know how many frames you wish to link, in order to calculate the max. power drawn

(4) evaluate the results

(5) about this cable calculator

And now the details:

Please select the frame type you're using. Its power determines very much all other electrical data. Please know that the power data given includes the maximum values (at 100% white), as well as the minimum values (base cosumption, not shown), to calculate the true consumption at a certain brightness level. If you enter an arbitrary value manually, no base consumption is assumed.

Set the brightness you're planning to use. Do so either by entering a value manually (numeric values 0...100), or use the slider. You should know that the power drawn goes very much parallel with the actual brightness, i.e. a Phantom II/60 draws appr. 100 W at 100% white, whereas colors, or reduced brightness, reduces the power according to the maximum and base power consumption (ref. frame type).

Please select the length of the cable running from the last frame to the plugbox, or to the PSU if no plugbox is used. Common cable langths are available for selection; use the 'arbitrary...' item if you wish to specify your own cable langth.

Please select the (average) length of the cables used to link frame to frame. This is actually a little weak point in this calculation: it does not allow for different lengths between different frames - but this would massively reduce the program's usabililty. To be safe, just select your maximum link cable length; but using an average is also not too bad. Try it, and see the difference to get a feeling. Again: use the 'arbitrary...' item if you wish to specify your own cable langth.

And again:

Please select the length of the multicore, to connect the plugbox with the PSU. If no plugbox is used (speakons directly run to the PSU), use the item '0 m - speakon directly into PSU'. Again: use the 'arbitrary...' item if you wish to specify your own cable langth.

And again:

Whilst you entered the frame type and cable length data, the values in the table below have already changed accordingly; now it's time to have a quick glance.

The details (e.g. current, or voltage drop) are the facts which determine the entire thing we're calculating; but they are something for real electricians. For us, the results are more interesting. Basically, everything is about that all frames need at least the minimum voltage - otherwise they might start flashing, or some other strange behaviour.

- entirely gray rows indicate valid combinations of cables and frames. At that stage, the column 'max length multicore' is certainly the most important: it gives you an idea which options for wiring are available.

- red rows indicate that this number of frames with this combination of cables doesn't work: short your cables, reduce the number of frames, or reduce the brightness. For obvious reasons, it is not possible to calculate exact power consumption for such invalid combinations.

- light-yellow cells indicate a power > 1,200 Watts at max. possible multicore length, which is more than possible with Version 1 PSUs (4 power blocks). Usually this gives problems only if you exceed this limit greatly or over a long time, but you'd better be aware of it. Don't be too concerned; this value will change with the next step (exact multicore length).

- yellow cells indicate a power > 1,500 Watts at max. possible multicore length, which is more than possible with Version 2 PSUs (2 power blocks). Usually this gives problems only if you exceed this limit greatly or over a long time, but you'd better be aware of it. Don't be too concerned; this value will change with the next step (exact multicore length).

With those data, you're able to determine whether your desired installation is basically within the electrical limits or not. If for your desired number of frames the max. allowed multicore length is already close to the length you intend to use, and you're expeting lots of full-white content, you might already reconsider your cabling (see the note at the very top).

Just click on the desired frame number's button 'last frame', and the program will calculate the exact values for the very multicore length you're using. This might even change the light-yellow or yellow cells; also, the total power consumption will slightly change. To indicate which frame number you just calculated, the corresponding row will turn green.

Just a couple of things you should keep in mind (most of them already mentioned above):

- the input power of the first frame (well, the last in the power chain) must not be lower than 36 Volts; actually, we regard 37 Volts as a minimum for safe operation. This tool helps you determine whether this condition is met or not.

- the number of frames, and the length of the links, feeds, and multicores, very much determine the total power consumption

- if you encounter problems with your chosen installation, (a) reconsider the cabling, (b) bring the PSUs closer to the frames (thus shortening the multicores), (c) reduce the number of frames per PSU, or (d) reduce the panel brightness (and use the fader here to re-calculate the power drawn)

- if you're just slightly above the limits, and there's no way to change something alike, it's worth a shot to split the frame's group, and wire both parts independently to the plugbox, using the two speakon outputs per channel. This is currently not to be calculated with this tool.

- finally, cross-check the total power consumption of both channels per PSU ( = the PSUs total power consumption) with the mains distro's voltage/rating

This tool was originally written as an Excel/OpenCalc spreadsheet, when I bumped into the idea to translate it to HTML/JS in Oct. 2007. The values computed have proven true (which is: very close to reality, cable lengths +/- 2 m) on several installations.

Please feel free to contact me (the author) in case of questions, problems, or improvements (or just to let me know if you find this useful):

Sebastian Beutel - sebastian.beutel@g-lec.com or s-beutel@gmx.de

G-Lec InfoMail - info@g-lec.com

G-Lec Website - http://www.g-lec.com

and finally:

the inofficial G-Lec technician's blackboard - http://www.jobbbs.de/g-lec

This is version 1.1 of the calculator, issued august 2008.

May 2006 - first Excel version

Nov 2007 - HTML/JS calculator version 1.0

Aug 2008 - HTML/JS calculator version 1.1

- slider for easy brightness setting added
- correct power consumption values
- base consumption calculated
- iteration problem with some values fixed (thanks to A. Lehrke)
- JS-Problem with help fixed (thanks to C. Muessener)
- power limitation added

number of frames to be connected to

Frame No. | min. voltage [Volts] | max. current [Amp] | total current [Amp] | voltage drop (link cable) [Volts] | min. voltage into link cable [Volts] | voltage drop from plug box [Volts] | min. voltage at plug box [Volts] | max. length multicore [Meters] | total power with max. multicore [Watts] |