Table 21: Rs-485 Terminations - ABB XSeriesG4 User Manual

7.4.7 RS-485 Communication Test
Tools needed:
-Oscilloscope
-Flat head tweeker screwdriver
To perform an RS-485 communication test using an oscilloscope:
IMPORTANT NOTE: Voltage on the following steps may be hard to see using a multimeter. If available, an
oscilloscope will provide a more accurate reading. To verify, the host software must be continuously polling the
meter.
Open enclosure
Measure line driver voltage, using an oscilloscope, on the circuit board J4 between:
a. COMM 1, pin 7 (BUS-) and COMM 1, pin 5 (BUS+)
b. COMM 2, pin 13 (BUS-) and COMM2, pin 12 (BUS+)
IMPORTANT NOTE: When the unit is receiving data from host, voltage should vary between -5Vdc and 0Vdc.
This would indicate that the unit is receiving data, continue to step 3. If unit is not receiving data, investigate wiring
issues (Table 19:).
Using an oscilloscope, measure remote request J4 to send (RRTS) voltage J6 between:
a. COMM 1, pin 2 (Ground) and COMM 1, pin 8 (RTS) or
b. COMM 1, pin 2 (Ground) and COMM 2, pin 14 (RTS).
IMPORTANT NOTE: When the unit is receiving data from host, voltage should vary between +5Vdc and 0Vdc.
This would indicate that the RRTS is receiving data. If unit is not receiving data, investigate wiring issues (Table
19:).
Call Totalflow Technical Support for additional help. If a communication problem still exists, and the unit has passed
the tests in steps 1 and 2, additional testing will be required.
CAUTION – Equipment Damage: Before removal or installation of either the above communication interface
!
modules, it is important that you disconnect the external battery charger and main battery pack cable connectors
from the circuit board.

Table 21: RS-485 Terminations

Communication Port
Jumper
First or Intermediate Unit
Last or Only Unit
160
1 2
J11 J12
pins 2–3 pins 2–3
pins 1–2 pins 1–2
XFC G4 2103335 Rev AB