Rockwell Automation 1788 NetLinx Media Checker Users Manual - Manual (Page 26)

26 Testing the Wire Map (WIRE MAP)
1788-UM002A-US-P – April 2000
Table 11. DeviceNet Wire Map Failures (with Cable ID)
Display Failure Description
Miswire (wires
are swapped) “H” and “+” are blinking. The first line on the display (LH +- S) shows the
near end connections. The second line (L+ H- S) shows far end
connections. This mapping shows that the H and + wires are swapped.
Short The S and L wires are shorted together.
Open, or a wire
is swapped with
the shield “o” is blinking in the bottom line. The “+” wire is open at the far end or is
swapped with the shield (S).
Multiple shorts* “ss”, “L-”, and “o” are blinking. “ss” blinking indicates a short from L to S.
“L-” blinking indicates a fault between the L and – wires. Use TEST or
LENGTH to check the resistance between the wires.
Split pair If nothing is blinking, the connection is good. If part of the display is
blinking (for example, “+-” in both rows), there is a split pair, or a fault that
the MediaChecker cannot clearly identify because the fault interferes with
testing.
* The MediaChecker alternately displays “??” and “RA” when the Cable ID is detected, but a problem with the cable or with the Cable ID is
interfering with the identification process.