Basics Of The VM-417 Diagnostic CCTV Meter
By Christian M Gillman
For surveillance installers a Difinitron VM-417 can at times be a very powerful tool in their arsenal for diagnosing video signal problems in a customers surveillance system.
What Is The VM-417
A VM-417 is a video test meter that allows an installer to test a CCTV cable line and make sure that certain levels are within their operating range. This meter tests to make sure that your sync, composite video, luminance, and color burst levels are all within operating ranges; as well as being able to help adjust your focus.
Furthermore the VM-417 is manufactured by Difinitron and it is made in the USA.
What Each Measurement Corresponds To
1. Sync Level Measures the amplitude of the video synchronizing pulse.
2. Video Level Measures the overall amplitude to determine Peak to Peak level.
3. Luminance Measures the white level of video.
4. Color Burst Measures the color burst amplitude of a color camera.
5. Focus is the maximum reading that corresponds to the most accurate focus.
Example Of Use
A great use for this meter can be to measure your video levels on a surveillance system that is using a video distribution amplifier. The reason for this is that if you find yourself trying to troubleshoot a surveillance system that has a faulty signal or no signal at all, and it is using one of these; the problem may lie within the level adjustments of the distributor.
A lot of video distribution amplifiers have their own adjustable levels for sharpness, brightness, etc... and if these levels are out of whack, then it can cause a failure. A quick way to test this is by testing your video levels before it reaches the amplifier, and then after it leaves the amplifier. If the levels are fine going in, but they are off when they come out; then your problem lies in the distribution module.
At this point it is a simple matter of fine tuning the adjustments on the distributor until the levels reach an acceptable range.
Now this fine tuning of the amplifier can be done without using a VM-417 test meter to confirm the diagnosis, but it will be a lot trickier as you wont know what levels are currently out of whack, and it will be a total "guess and test" in changing the adjustments.
Made For Installers
The VM-417 CCTV meter is a very impressive tool for diagnosing surveillance systems; however it is definitely designed for an installer and surveillance system designer to use. The reason being that it generally prices around $600, and this is not a cost effective solution to buy for use by a single end user.
VM-417 Optional Equipment
The VM-417 has an optional protective case for use in more hazardous environments. The OBC-12 is a highly visible orange case that is made for the VM-417 and it is made of a highly durable rubber. Furthermore this case can even accommodate other CCTV test meters.
Christian M Gillman has worked in the surveillance industry for over 6 years. Subscribe to our monthly newsletter, learn more about surveillance, and find great products at http://www.cu1.com.
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