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4
HARDWARE TROUBLESHOOTING AND ANALOGUE INPUT
INSPECTION
This chapter illustrates the most frequent hardware faults and gives some information on their possible causes
and solutions. It also describes the procedure to be followed to check the analogue inputs in the controller
board.
4.1 Network faults
Below is a list of the main problems which may occur in a line.
Problem
Possible causes and solutions
The terminal buzzer sounds for no
reason. When it stops sounding,
the display is cleared (hardware
reset).
- The same address has been given to several components.
Check the configuration of the addresses.
One or more terminals have the address set to "0".
Check the configuration of the addresses.
- The network connections have not been made correctly. - The data
lines (tx+ / rx+ and/or tx- / rx-) may be short-circuited to earth or
disconnected.
Check the connections.
- A pCO board may be damaged.
Although it is powered, the display
of some terminals fails to show
data.
Access the configuration procedure pages. If the address field is "-" in
the “I/O board Adr” line, the terminal has not been configured.
Configure the terminal.
The alarm screen appears
showing "NO LINK".
- The terminal is not receiving signals from the network, the
connections are disconnected.
Check all the connections to the network.
There are no network components connected to the terminal.
The “I/O board xx fault” alarm
message appears.
- The power board with address "xx" is not working properly.
Check the LEDs of the corresponding serial addressing board.
The green LED fails to come on in
the pCO* board.
- The board involved is not receiving the network signal: the
connections are incorrect.
Check all the connections.
There are no other components connected to the network.
The green LED in the pCO* board
switches on and off periodically.
- Go back to the first item.
The unit will not get started
(network detection LED on the
pCO* off, LCD off, other LEDs
off).
Check that the network is energised.
4.2 Other faults
Problem
Possible causes and solutions
When the unit is switched on, the
line LEDs or the three pLAN LEDs
are ON or either no texts or
random texts appear on screen.
- Problems are detected in the Flash Memory.
Contact our Service Department.
Incorrect reading of incoming
signals.
- Check the calibration of the inputs (as per program).
- Check that the pCO* and the probes are powered correctly.
- Separate the power supply to the digital inputs from the power supply
to the pCO* using a 24 Vac/24 Vac transformer of at least 12 VA.
- Check that the wires in the probes are connected correctly.
- Check that the probe cables are at a sufficient distance from possible
sources of electromagnetic interference such as power cables, cable
contactors with high voltages and with devices connected having high
starting current draw.
- In the event of a probe error or a pCO* conversion error, refer to the
"Analogue input testing" section.