Table 20: Rs-485 Field Wiring On Xfc Board J4 A And B; G4 Board J4 A And B - ABB XSeriesG4 User Manual

IMPORTANT NOTE: When the unit is receiving data from host, voltage should vary between -5Vdc and +5Vdc.
This would indicate that the unit is receiving data, continue to step 3. If unit is not receiving data, investigate wiring
issues (Table 19:).
Measure, using an oscilloscope, Request to Send (RTS) voltage on electronic board J4 between:
a. COMM 1, pin 1 (Ground) and COMM ,1 pin 8 (Request to Send)
b. COMM 1, pin 1 (Ground) and COMM 2, pin 14 (Request to Send)
IMPORTANT NOTE: When unit is communicating with the host, voltage should be +5Vdc and remain +5Vdc until
the flow computer transmit stops. This would indicate that the unit is transmitting data. Continue to step 4. If unit is
not receiving data, investigate wiring issues (Table 19:)
Using an oscilloscope, measure transmit data (TXD) voltage on electronic board J4 between:
a. COMM 1, pin 1 (Ground) and COMM 1 pin 4 (Transmit Data) or
b. COMM 1, pin 1 (Ground) and COMM 2, pin 12 (Transmit Data).
IMPORTANT NOTE: When the unit is transmitting to host, voltage should vary between -5 Vdc and +5Vdc. This
would indicate that the unit is transmitting data. If unit is still not responding, continue to next test as directed in
Figure 102:
7.4.6 RS-485 Communication Test
The following RS-485 Serial Communication Test procedure is directed from Figure 102: and will assist the user in what may be
the possible cause for indicated error message.
Before performing this test, please verify that the field wiring (Table 20:) is correct.
IMPORTANT NOTE: When troubleshooting RS-485 mode, verify termination settings of COMM 1 J11 and
COMM 2 J12 on XFC
G4
board are correctly jumpered (Table 21: ).
Table 20: RS-485 Field Wiring on XFC
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
159
G4
Board J4 A and B
Description
Ground
VBattery
Switched VBattery
TXD/BUS+
BUS+
RXD/BUS-
BUS-
RTS
N/A
N/A
N/A
TXD/BUS+
RXD/BUS-
RTS
N/A
Operate
XFC G4 2103335 Rev AB