Moog Inc., Components Group, Halifax Operations
Focal Technologies Corporation
77 Frazee Avenue
Dartmouth, Nova Scotia, Canada B3B 1Z4
Tel: 902-468-2263 • Fax: 902-468-2249
[email protected] •
www.moogpowerdata.com
Application Note
This document is the property of Focal Technologies Corporation, and may not be neither copied, reproduced or otherwise dealt with nor its
contents communicated to others except in accordance with written instructions received from Focal Technologies Corporation.
700-0290-00 Rev. 1
Page 2 of 6
MOST COMMON VIDEO PROBLEMS
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Improper impedance matching (75 ohms) or missing ground connection
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Video signal “too hot”, i.e. >> 1 Vpp nominal. (Camera outputs may be set to drive long copper cables.)
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RG-179 OK but attenuates at higher frequencies, so limit to a few meters or use RG-59 for long runs
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Isolation required, e.g. Deerfield Labs transformer (grounding problems between camera, mux, monitor)
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Wrong jumper settings on video card for composite versus S-video (Y/C) and RGB (see user's guide).
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Anti-piracy protection on VCR tapes or DVDs during testing (e.g. Macrovision)
MOST COMMON DATA PROBLEMS
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Improper RS-485 auto sense settings (refer to manual for proper settings)
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AIB plug-ins not installed in proper orientation or socket, or different card types used in remote and console end.
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Incorrect RS-485 polarity: Focal standard is negative pin is inverting and RS-485 biased with 619 ohm pull
up/down resistors plus optional 120 ohm terminator. When the two-wire polarity is correct, the red receive LED
is typically on less often then when the wires are reversed.
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No or poor terminations: terminators and impedance controlled cable is needed at high data rates (> 500 kbps).
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Poor cabling or grounding: Use twisted pairs for differential serial links. Verify proper grounding and shielding.
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AIB switch settings: Incorrect or default settings need to be changed.
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RS-422 Cross-over: Pins 1, 2 (Mux Rx) and 3, 4 (Mux Tx) are the same at both ends. Hence RS-422 coming
into the mux on pins 1/2 at one end will exit the mux at the other end on pins 3/4 for the corresponding channel.
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MS900 AIB settings: Jumper on AIB must be set one way for the remote and the opposite way for the console.
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ARCNET AIB settings: Mux and sonar settings must match, per manual.
MOST COMMON OPTICAL PROBLEMS
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Bad or contaminated connections (excessive loss and/or back reflection) cause 80% of all link problems.
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Excessive fiber bends or damaged cables cause excessive optical loss, particularly at 1550 nm.
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Insufficient fiber bandwidth, particularly in multi-mode fiber, can cause intermittent problems on long cables.
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Optical overload (not enough attenuation) during bench tests can cause link faults or errors.
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Dust contamination from bushings or connectors not being covered (especially turrets) can cause link faults.
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Mixed multimode/singlemode fiber jumpers (orange/gray vs yellow jackets) cause optical faults.
FIBER HANDLING GUIDELINES
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Never use the fiber to pick up or support the weight of the device to which it is attached.
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Do not exceed the minimum bend radius (typically 1" for many loops, 0.5" for single half loops).
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Never clamp down on fiber. For example, when securing the fiber to a PCB, do not use a tight string, clamps or
any mechanical mean to tightly bind the fiber. Local stress on the fiber increases loss and may break the fiber.
Hard epoxies should also be avoided when securing fibers on a PCB.
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Follow ESD guidelines for handling electrostatic sensitive devices, such as cards with electro-optical devices.
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Clean all optical connectors (tips and barrels), bushings, adapters, and attenuators before use.
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Momentary violations of bend radius or excessive lateral pressure may significantly reduce the long term
reliability of fiber, even if it appears undamaged. When in doubt, do not use the fiber.
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Always use dust caps on bushings, turrets and connectors, especially on turrets.
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Ensure connectors are well secured in the bushing and are not side loaded.
