Rockwell Automation 1770 DH,DHII,DH485 CABLE - Manual (Page 40)

Chapter 3
Constructing a Data Highway or
Data Highway Plus Cable System
3-8
Test the Connector for Electrical Shorts
After you have soldered the connector to the dropline, you must check for
electrical shorts. To do this, measure the resistance between:
the blue conductor wire and the drain wire
the drain wire and the clear conductor wire
the clear conductor wire and the blue conductor wire
If the resistance readings you obtain indicate there are no shorts, you are now
ready to attach the dropline to a station connector. Refer to the section later in
this chapter.
If the resistance readings you obtain indicate an electrical short exists, check the
other end of the dropline for a station connector.
If the dropline: Then go to this procedure:
Does not have a station connector ``Electrical Short Exists and Dropline
Does Not Have Station Connector"
Has a station connector ``Electrical Short Exists and Dropline
Has Station Connector"
Electrical Short Exists and Dropline Does Not Have Station Connector
Check for frayed wire or wire fragments at the electrical connector, or at the
other end of the cable. Check the resistance readings again.
If the resistance readings: Then:
Indicate there are no shorts Attach a station connector to the dropline. Refer to ``Selecting the
Type of Station Connector" in Chapter 2 for guidelines on choosing
the station connector appropriate for your application.
Indicate that a short exists Disassemble the electrical connector, try to locate and repair the
short, and test the resistances again.
After finding and repairing the short, test the resistances again:
If the resistance readings: Then:
Indicate there are no shorts Attach a station connector to the dropline. Refer to ``Selecting the
Type of Station Connector" in Chapter 2 for guidelines on choosing
the station connector appropriate for your application.
Indicate that a short exists The short is probably inside the dropline cable. Discard the
dropline cable and attach the electrical connector to a new piece
of cable. You may remove the connector from the discarded
dropline and reuse it on the new dropline.