Cool Tools: Testers
Published: June 2012
No alarm, surveillance or control system can be considered complete until tested to confirm it meets industry standards and will perform to specifications.
Field-testing installed communications cabling is critical to ensure the proper operation of security and life safety systems, said Dan Payerle, business unit manager at Ideal Industries (www.idealindustries.com).
“Even the most experienced installer can make routine mistakes that are not obvious through visual inspection and only become evident when tested,” Payerle said. “And while rare, defective components can also find their way into an installation. Trying to find a defective component that is the source of a performance problem without the assistance of a field tester can lead to many hours of trial-and-error troubleshooting.”
Andre Rebelo, Extech (www.extech.com) global communications manager, emphasized that there is no room for error when wiring and testing security and life safety systems.
“Without exaggeration,” Rebelo said, “people’s lives depend on a properly tested configuration. Proper testing also means getting the job done right the first time. Missing a fault in wiring or fiber can result in installations that run long as the task switches from systematic testing to hunt-and-peck troubleshooting.”
A network is totally dependent on adequate cabling infrastructure for successful performance, said Harley Lang, Fluke Networks (www.flukenetworks.com) product marketing manager.
“Cabling is only as good as the quality of the installation practices and components,” Lang said. “Unless it is certified with a cable tester, it cannot be known if a link or channel will be able to support the demands of the network. Most network owners and contractors own multiple types of tools and use them selectively for the tasks they undertake.”
Ideal’s Payerle said most basic yet essential testing is for proper continuity and polarity. For coaxial and twisted-pair cabling, a basic wire map tester will catch the vast majority of problems associated with termination errors.
“When selecting a wire map tester, make sure that it includes a test for split pairs,” he said. “The most inexpensive testers omit this critical function and will pass a cable that in actuality will not operate above 10 Mbps, even though the installer expects the Cat 5e or Cat 6 cabling to operate at 1,000 Mbps or more.
“For coaxial cabling used in video surveillance, it is important to test the loop resistance of the runs to ensure good picture quality. It can be tested with a simple digital multimeter using the ohms function. The loop resistance should be no more than 10–15 ohms. Test it by shorting the center conductor to the shield at one end of the cable and measuring the resistance across the center conductor and shield at the other end. One of the most typical causes of picture quality issues is the use of copper-clad steel coaxial cable rather than 100 percent copper coaxial. Copper-clad steel is used in CATV/satellite applications but should never be used for CCTV,” Payerle said.
Continuity and polarity tests ensure the fiber is not broken and that it is routed to the intended location.
“Continuity testing is performed with a visual light source, which can be an LED [light-emitting diode], laser or even an incandescent flashlight with an adapter to hold a fiber optic connector. After testing continuity, optical fibers should be tested for insertion loss to make sure that there is no excessive power loss from bends or poor terminations,” Payerle said.
The cost of testers varies widely based on functions and capabilities. Payerle summarized testers and cost ranges for testers for the three primary types of cables used in security, alarm and control systems.
A wire mapping tester with split-pair capability ($75–$300) is the minimum required test. Additional features such as length and TDR capabilities and support for multiple remotes can speed up troubleshooting. Wire mapping tests do not measure the performance of the cabling; they only verify that continuity is correct.
To measure the performance of twisted-pair cabling, there are two classes of field testers available. Qualifiers ($1,000–$1,500) work by performing a series of tests that ensure the cabling will support the desired application, most commonly gigabit Ethernet.
Beyond qualifiers, certifiers ($5,000 and up) can be used to test all the electrical and radio frequency (RF) characteristics of the cabling to verify that the installed performance meets industry standards such as Cat 5e, 6 or 6a. Certifiers also are used to providing warranty coverage that may be offered by the cable and connectivity manufacturers.
Many twisted-pair wire mappers also include adapters to test coaxial cable for continuity and length, Payerle said. For CCTV applications, a digital multimeter ($25–$300) is essential to test loop resistance (less than 15 ohms) and port termination values (76–90 ohms). There also are specialty CCTV meters available ($400–$800) that test the voltage level (measured in IRE units) coming from a camera, which is useful in troubleshooting camera and cabling issues.
Payerle classified the most basic tester as an LED continuity device ($25–100) that can be used to check the continuity of short multimode cables. A step up is a visual fault finder ($200–$350) that uses a powerful laser light source instead of an LED. The laser injects more power, making the tether useful on both multimode and single-mode cables at distances of several miles. Additionally, the laser light will shine through most plastic buffer tubes, which helps the technician visually locate bends, kinks or breaks in individual fibers.
An optical power meter and light source test kit ($500–$3,000) measures optical power loss in a system.
“This is vital when testing that loss of the cabling system is matched to the electronics in the optical network. Optical receivers operate within a certain range of power and an optical test set is the only way to ensure proper operation of the system,” Payerle said.
Most mid-range testers for twisted-pair cabling will have at least some capability to test coaxial cabling by using adapters, he said. Performance qualifiers and certifiers usually can test twisted-pair, coaxial and fiber optic cabling.
“A qualifier with fiber optic options can be had for about $2,000 and provides testing and printed documentation to prove the performance of the installed cabling system,” Payerle said. “Fully loaded certifiers with all the options for coax, multimode and single-mode fiber optic testing can cost $15,000 or more.”
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at email@example.com.