Installation Manual

Versus Technology, Inc.
DT10000-A0001 24 Revision 8 December 1998
8. INSTALLING AND CHECKING COLLECTORS
Locate the punch block and collector unit(s) carefully to allow for wiring access, neat wire routing and dress,
and expansion space for future collectors that may be added as the system is expanded.
8.1 Checking the Collector Wiring
A quick visual check of the collector wiring should find that the punch block is secure and that the collector unit
connector is firmly seated against the punch block connector. See section 13.1 the Collector Voltage
Troubleshooting Flow Chart for checking the collector wiring.
The collector network (2-pair) must be tested before the system power is applied to be sure that wires are not
misconnected. Failure to thoroughly test the collector network wiring may result in equipment damage.
The concentrator and collector devices connect to the 2-pair wiring system using modular interfaces to allow for
easy testing of the wiring before power is applied. It is recommended that install crews be equipped with
appropriate USOC cable testers as required to verify the polarity and validity of installed wiring.
Note that 3-pair USOC interconnections may also be used. In this case, the third pair (outermost) will be used
in parallel with the second pair to improve power distribution to the collectors.
8.2 Checking Isolation
In the course of interconnecting many sensors to a collector, it is not uncommon to make contact with a sharp
metal edge, ganged knockout box, or electrical ground with one of the conductors. It is critical, however, that
such accidental connections be located and cleared prior to system start up. The effect of these accidental
connections can range from mild too severe. In many cases, erratic behavior may be noted. In some cases,
equipment damage may occur. In any case, an electrical code violation has been produced.
To verify that the system is "isolated" from building and electrical grounds, use an ohmmeter or multimeter set
to the 2K (2000)-ohm scale. Clip one probe to the nearest electrical conduit, electrical ground, or metal water
pipe and then touch the other probe to each punch block row in turn. Every row MUST indicate an infinite
(open) connection. If this is not the case, the suspect line must be traced to find the accidental connection to the
structure that has been made.
NOTE:
It may be helpful to disconnect the collector from the punch block while this measurement is
being made. This will isolate the sensor wiring completely.
CAUTION:
Correct two-pair wiring is essential. Crossed or reversed pairs can cause equipment damage
in some cases. ALWAYS TEST ALL WIRING PRIOR TO CONNECTION OF SYSTEM
POWER SOURCES.