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FREQUENTLY ASKED QUESTIONS
Question #1: What is voltage drop, and how can I calculate it for my application?
Question #2: What is video resolution?
Question #3: I am using Under Pressure Software, and get an error about "Can't                          Parse that value." What is causing this, and how can I fix it?
Question #4: Do you sell used equipment?

Question #1 Back to top
  What is voltage drop, and how can I calculate it for my application?
Answer: In many cases (especially with low voltage lights), the output voltage from the power supply must be much higher than the lamp voltage. The reason for this is that a significant amount of power is lost due to the electrical resistance of the power cable.
 
  The voltage drop over a length of cable can be calculated by using the formula, V = IR, where V is the voltage drop, I is the current draw of the light in amps, and R is the total electrical resistance of the power cable in ohms. The current draw of a particular lamp can be calculated if the wattage and voltage of the lamp are known. The current draw is equal to the lamp wattage divided by the lamp voltage, or, amps = watts/volts.
 
  For example, referring to the table of electrical resistance's of various wire gauges listed below, we can calculate the voltage required to operate a 24 volt-300 watt light at 24 volts over 250 feet of 16 gauge cable. The current draw, I, of a 24 volt-300 watt lamp operating at 24 volts is 300 watts/24 volts = 12.5 amps. The resistance of 16 gauge wire is approximately 4 ohms/1000 feet. Since the total path of the circuit is from the power supply to the light and back to the power supply, the total resistance of the cable is twice the length of the cable times the linear resistance, or for this example, R = (2 x 250 ft) x (4 ohms/1000 ft) = 2.0 ohms. Since V = IR, the voltage drop, V is equal to 12.5 amps x 2.0 ohms = 25 volts. This means that 25 volts is lost due to resistance and so the power supply will need to provide at least 49 volts to power this 24 volt-300 watt light over a 250 foot cable!
Wire Gauge Ohms/1000 ft (approx)
20 10
18 6
16 4
14 2.5
12 1.5

Question #2 Back to top
What is video resolution?
 
Answer: Resolution is the ability of a camera, monitor, or system, to represent fine detail. The better the resolution, the more detail is perceivable to the observer (man or machine). Several factors contribute to the level of resolution in a system, including the quality of the camera and the monitor, the quality of the transmitting equipment, and the number of active scanning lines. TV images are two dimensional, thus we are concerned with resolution in two dimensions, vertical and horizontal.
 
  Vertical resolution is defined by the number of vertical elements that can be captured by a camera or reproduced on a monitor. Vertical resolution is measured by the number of alternate black and white horizontal lines that can be distinguished in the height of the camera image or display picture. The number of active lines are generally referred to as approximately 575 lines for CCIR, and 480 for EIA, yet these figures still do not reflect realized vertical resolution.
 
  In the mid 1930's it was determined that a correction factor (K factor) of approximately 0.70 times the number of active scan lines was required to achieve actual vertical resolution figures for tube type cameras and displays. This correction coefficient takes into account monitor over-scanning, brightness tradeoffs, limitations in electronic beam width, as well as grill mask limitations in color imaging. With this correction factor, vertical resolution of a CRT is generally reduced to a practical value of 400 lines PAL/CCIR, and 330 lines for NTSC/EIA. Other types of cameras and displays which do not use a scanned beam (CCDs, LCDs, EL, Plasma) are able to approach a K factor of 1.0. Often these devices will only offer 240 active scan lines however. An LCD with 240 scan lines, even with a K factor of 1.0 will only reproduce at most 240 vertical lines of resolution. Vertical resolution is dependent on the system technology and is largely independent of system bandwidth.
 
  Similarly, horizontal resolution is defined by the number of horizontal elements that can be captured by a camera or reproduced on a monitor. Horizontal resolution thus tells us how many alternate black and white vertical lines can be discerned in the width of the image. In order to make this number comparable to the value determined for the vertical resolution, the horizontal resolution is multiplied by .75 to correct for the difference in the picture height to width ratio (3:4). Horizontal resolution is highly dependent on system bandwidth.
 
  In conclusion, vertical resolution for most CRTs is typically based on the standards for television receivers, 400 TV lines for CCIR, and 330 TV lines for EIA. Since it is independent of system bandwidth it is often considered fixed for a given video standard (e.g. PAL or EIA). However, horizontal resolution remains variable and is related to the camera or display's horizontal resolution as well as factors such as the quality of the transmission media (cables, etc.) and system bandwidth. When "resolution" is discussed for camera comparison purposes it is generally presumed to be horizontal resolution. Like a chain, resolution of a video system is only as good as its weakest link. Solid state cameras (e.g. CCDs) have overcome many of the limitations of tube type cameras and are able to more closely achieve their theoretical resolutions (number of vertical and horizontal pixels).

Question #3 Back to top
I am using Under Pressure Software, and get an error about "Can't Parse that value." What is causing this, and how can I fix it?
Answer: The problem that you are having appears to be from the "Numeric Parser", which is the part of the program that takes the input numbers (including grouping symbols, decimal symbols, and engineering units) and converts them into a value that it can work with. Due to difference in how Europeans and Americans (and others, on both side of the equation) represent their digit grouping symbol, and decimal symbol, this is a somewhat complicated problem.
 
  In the US, we represent values using commas (",") as grouping symbols, and periods (".") as decimal symbols. So we would write 38,420.23 whereas in Europe it would be written 38.420,23, to represent the value "Thirty eight thousand, four hundred twenty, and twenty three one hundredths".
 
  Windows has a configuration option that declares what the digit grouping symbol, and decimal symbol are, and these choices are used by the "Parser" in the program to figure out what the numbers are.
 
  If a computer is set up for European units, and it sees a US format number such as "38,420.23", or even something as simple as "4.08" it stumbles, because it expects 3 digits between grouping symbols (as a place holder - which, because it is in European units, it thinks should be a ".").
 
  From your description, it looks as if there is some conflict between what the computer is set up to use as its units, what is being put into the computer as input, and the file format that it is opening. For instance, if the computer is set up for European units, then the information for the program must be entered in European format (using "." as the place holder, and "," as the decimal mark). Also, if a European configured system tries to load a file saved on a US configured system that will result in the same problems.
 
  Here is a common fix for this problem -
Assuming that you are running on Windows 98 or NT, go to Start, Settings, Control Panel, double click on Regional settings, select the numbers tab and then:
  1. What is the Decimal symbol? It should be "," for a European configured computer, and "." for a US configured one.
  2. What is the Digit Grouping symbol? It should be "." for a European configured computer, and "," for a US configured one.
         Are you trying to load example files? If so, please be sure to load the European format examples if your system is European configured. These should have been loaded with your install.
 
  If you are inputting numbers from scratch, are you using European format - i.e. 38.420,23 with a European configured computer? If the computer is configured for European input, then the values must be input to match this format.
 
  Are you using this program on multiple computers, where one computer may be configured in US and the other in European units? It is easiest to have both computers configured the same, so that they can share files.

Question #4 Back to top
Do you sell used equipment?
Answer: No, all of the products we sell are new and rigorously tested before leaving our facility. Our products provide the "Best Value" for the needs of our customers. Each product comes with the full confidence and backing of DeepSea Power & Light, and is guaranteed with a one year warranty.

 
 
 
 
 
 
 
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