ABB ACQ550-x1-06A6-2 User Manual page 195

ACQ550-U1 User's Manual
Troubleshooting
The troubleshooting table below should be followed in order from top to bottom by
parameter number. Begin the troubleshooting process by displaying the first
parameter in the table (5308) and determining if the display on the panel exhibits the
symptom. If it does, review the possible cause(s) and take the necessary corrective
action(s). Once the symptom for this parameter is eliminated, continue to the next
parameter and repeat the process until you have reached the end.
Parameter
Number
5308
UART
ERRORS
5307
(5007)
DV CRC
ERR
Display on
Panel Possible Cause
(Symptom)
Rapidly 1. Duplicate
Increasing Addresses
Numeric
1
Value
2. Swapped Wires
3. Incorrect Baud Rate
4. Incorrect Parity
5. Too many devices
on wire
6. Incorrect Bias
7. Noise on EIA-485
wire
8. Blown EIA-485
transceiver
Rapidly 1. Duplicate
Increasing Addresses
Numeric
2. Too many devices
1
Value
on wire
3. Noise on EIA-485
wire
Corrective Action
1. Ensure EFB PROTOCOL parameters
5302 [also 5311 & 5317 when using
BACnet] are unique. 5302 must be a
unique address on the segment. [5311 &
5317 must be unique addresses on the
network when using BACnet.]
2. Swap wires B(+) & A(-).
3. Adjust parameter 5303 & Cycle power.
4. Change parity using parameter 5304 &
cycle power.
5. Limit to 31 devices on 1 segment.
6. Turn off VFD termination resistors (move
jumpers). Install loose resistor
recommended by the DCS controls
company. (Terminate final device on the
trunk.)
7. Install EIA-485 (3 conductor shielded)
data grade cable communications wire.
See drawings on page 180.
8. Find and correct ground loop or high
voltage problems before replacing any
component assemblies.
Perform the following steps to determine if
the EIA-485 transceiver is damaged.
a. Power unit down.
b. Remove bus wires and retighten
connections.
c. Turn bus termination ON.
d. Measure impedance between B(+) &
A(-).
ACQ550 164 ohms +/- 5%
If measurements are not within the
specified range the EIA-485 transceiver is
bad, replace the assembly containing the
EIA-485 port.
1. See Corrective Action 1. Parameter
Number 5308
2. Limit to 31 unit loads on 1 segment
(ACQ550 = 1 unit load)
3. See Corrective Action 7. Parameter
Number 5308
Embedded fieldbus
195