Honeywell TA3840 Maintenance Manual page 18

Communication fault message for all analog
4-20 mA channels from one analog 4-20 mA
inputs board (channels 1 to 48 or 49 to 96).
Communication fault message for all analog
4-20 mA channels or On/Off inputs or On/Off
outputs from one multifunction board (channels 1
to 48 or 49 to 96).
Fail message for all analog 4-20 mA channels
from one analog 4-20 mA input board (channels 1
to 48 or 49 to 96).
Observation
Communication failure with any external
application, relevant Rx and Tx indicators don't
flash.
Communication failure with any external
application, relevant Rx indicator flash but not Tx.
(*) refer to the relevant paragraph in "REMEDIAL MAINTENANCE" chapter.
TA3840C A/D Communication unit
Observation
Indicator
5 Vdc off, despite power
supply switch on
and
No communication for all analog
4-20 mA channels from one analog 4-20 mA
inputs board (48 first channels or 48 further
channels).
(*) refer to the relevant paragraph in "REMEDIAL MAINTENANCE" chapter.
Doc No: MM5008E – Revision 6 – ENG
green LED 24 Vdc main
input off,
green LED 24 Vdc main
input on,
green LED 24 Vdc main
input on, power supply
board's fuse not blown out.
- No communication with the
relevant board.
- No communication with the
relevant board.
- Relevant analog transmitters
not powered, green LED
24 Vdc Analog Sensors off.
Likely cause
- No communication from the
external application.
- No communication from the
external application.
Likely cause
- 24 Vdc Power supply not
connected on TA3840C.
- Power supply board's fuse
blown out.
- Power supply board out of
service.
- No communication with the
relevant board.
Data Processing Racks
TA3840 Maintenance Manual
- Replace the analog 4-20 mA
inputs board (*).
- Replace the multifunction
board (*).
- Switch on (toward bottom)
the switch on relevant board.
Remedy
- Check and secure the cable of
connection with the external
application.
- Check the configuration of the
supply and communication
board (refer to the installation
manual).
- Replace the power supply
board (*).
- Check the TA3840C rack
address setting in the
external application.
Remedy
- Check the presence of the
24 Vdc on the terminal block
on rear face.
- Check the EMC filter.
- Replace the fuse F1 on
power supply board (*).
- Replace the power supply
board (*).
- Replace the analog 4-20 mA
inputs board (*).
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