Daikin MD5 - Page 57

Duplicate Stations
If two or more stations have duplicate numbers:
• Two or more drives cannot be addressed.
• Every time there is a read or write to one particular
station, the value for 5307 EFB CRC ERRORS or 5308
EFB UART ERRORS advances.
To correct: Check all station numbers and edit conicting
values.
Swapped Wires
If the communication wires are swapped (terminal A on one
drive is connected to terminal B on another):
• The value of 5306 EFB OK MESSAGES does not
advance.
• The values of 5307 EFB CRC ERRORS and 5308 EFB
UART ERRORS are advancing.
To correct: Check that the EIA-485 lines are not swapped.
Fault 28 – Serial 1 Err
If the drive’s control panel shows fault code 28 “SERIAL 1
ERR”, check for either of the following:
• The master system is down. To correct, resolve problem
with master system.
• The communication connection is bad. To correct, check
communication connection at the drive.
• The time-out selection for the drive is too short for the
given installation. The master is not polling the drive
within the specied time-out delay. To correct, increase
the time set by parameter 3019 COMM FAULT TIME.
Fault 31 – EFB1
For BACnet: If the drive’s control panel shows fault code 31
“EFB1”, the drive has an invalid Device Object Instance ID. To
correct, use parameters 5311 and 5317 and establish a unique
drive ID that is in the range 1 to 4,194,303.
Faults 31…33 – EFB1…EFB3
Except as noted above, these three EFB fault codes (listed for
the drive in Diagnostics on page 74, fault codes 31…33) are
not used.
Intermittent off-line occurrences
The problems described above are the most common
problems encountered with MD5 serial communication.
Intermittent problems might also be caused by:
• Marginally loose connections,
• Wear on wires caused by equipment vibrations,
• Insufcient grounding and shielding on both the devices
and on the communication cables.
• Two conductor wire (plus shield) is in use instead of the
recommended three conductor wire (plus shield), see
page 46.
eMbedded fieldbUs
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