Date post: | 07-Jul-2015 |
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Self Improvement |
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Always check the obvious!
Treat a digital switching installation like any traditional system
Is there a signal at the input?
Is there power feed to an output device?
Is their power coming out of the output device?
Does the configuration match the inputs?
Believe it or not incorrect wiring still happens with Digital switching installations. With any new technology the easiest diagnosis is to blame the system
Before You Begin
Are all modules online, with no conflicts?
If yes:
• System is ready to use
• Fault is elsewhere – start diagnosing other areas
Fault finding - Network
Are all modules online, with no conflicts?
If No – here are some possible codes you will see:
“Conflicting Module”
If a Conflict error is displayed then two or more modules have the same
dipswitch setting
• The module stating ”Conflict” has the correct setting
• The Module reporting ”Offline” is incorrect
Fault finding - Network
Conflicting Modules – Solution
Reset the dipswitch setting on the module to match the configuration tool:
1. Obtain the correct dipswitch setting for the module:
2. Unplug the NMEA2000 connection to the module and set the dipswitches to the correct setting
3. Reconnect the NMEA2000 cable
Fault finding - Network
Offline Modules
A module that is not communicating with the network will be identified as being “offline”
Alarms will also be raised on the displays appearing as a “Blue Bell” alarm.
The error message will state that there is a “Device Missing”
Fault finding - Network
Missing Modules - All modules are offline
Configuration related checks:
• The USB – CAN tool is plugged in correctly
• The drivers for the USB-CAN module have
been installed correctly on the PC
• The configuration tool has been opened
after the system has been plugged in and
turned on
Fault finding - Network
All modules are offline
Physical network checks:
• Check all network connections have been made and are tight
• At devices
• Along the backbone and “T” joiners
• Check power to the network
• At the point of the power connection
• At each end of the network (minimal voltage should be detected)
• Have both terminating resistors been fitted?
• Check for shorts on data and power pairs
• Have bridges been connected and powered correctly?
Fault finding - Network
Offline Modules
Physical network check:
• Check the network status LED on each module
The Network Status LED on each module has three functions:
• Green – Network power detected
• Red Flashing – Network activity
• Solid Red – Network failure such as shorted CAN high and low wires
Fault finding - Network
Offline Modules
Physical network check:
Voltage Readings on network conductors:
•Red to Black 12VDC (supply voltage)
•Red to Shield 12VDC (supply voltage)
•Blue CAN L to Black (Neg) around 2.5VDC
•White CAN H to Black (Neg) around 2.5VDC
Resistance between CAN L and H should be 60ohms with no devices on network
Recommend cutting an end off an extension cable to use as a testing tool
CAN connections can be accessed internally on smaller boxes for voltage testing
Fault finding - Network
Missing Modules
Only some modules are offline
Configuration related checks:
• Has the module got the correct Firmware
loaded for the network?
• All previously mentioned checks apply to
individual missing modules
Fault finding - Network
Fault - Switches not controlling the correct load as per the configuration
eg Galley light switch controls cabin fans
Potential cause - Swapped Dipswitches. A module may have the incorrect
dipswitch settings for its application.
Solution - Identify the module correctly in the configuration design and reset its
dipswitch settings accordingly
Fault Finding – Operational Anomolies
Fault - The correct load is switching but the control of the load is not as expected
eg. a) A horn stays on when a momentary control button is pressed
b) A load turns on or off in the opposite direction to the button press
c) A load, which has many switches for controls, can not be toggled on or off after one of the switches has been turned on or off
General causes:
Incorrect switch output function is selected in the configuration tool
Incorrect switch wiring i.e. normally closed instead of normally open
Incorrect switch type installed i.e. momentary instead of latched
Switches wired to wrong input
Fault Finding – Operational Anomolies
Fault - If a load does not turn on when controlled by a switch (or display)
Potential cause - The load wire is connected to the wrong output channel.
Remedy - Check on the OI/MOI which status LED turns on and that the load
wiring is connected to the correct channel
Fault - A load can be controlled correctly by a display but the circuit switch does
not control the load (or controls a different load)
Potential cause - The wiring into the SI or SCI is incorrect
Remedy - Refer to the installation instructions and wire devices to match design
Fault Finding – Operational Anomolies
Fault - A load cannot be controlled (turned off) -
Potential cause - The fuse may be in the bypass position. Look at the appropriate channel and ensure the fuse is in the “Normal” position
Fault - A load has turned off un expectedly
Potential Causes
1. Load Shedding is enabled for the circuit and a low voltage trigger point is reached
2. Power to the network or at least the controlling modules network has been lost resulting in all loads shutting down.
3. The main power supply to the CZone™ module has been lost
Fault Finding – Operational Anomolies
1. Disconnect all wiring connections then remove the faulty module
2. Ensure the Firmware on the replacement device matches the replaced device
3. Ensure all the dipswitches on the new module are switched to the off position
4. If the module is an OI or a MOI remove the fuses from the failed module and
fit in the same locations on the new module (to ensure bypass fuses match
load)
5. Fit the new module and connect all wiring except the NMEA cable
Replacing Damaged Modules
6. Once fitted temporarily connect the NMEA cable until all the indication lights
flash once. Then remove the NMEA connection. This has now wiped any
program that may have been on the module.
7. Set the dip switches to match the settings of the replaced module. Once the
dipswitches are set plug in the NMEA cable.
After a short period of time the new module will receive a copy of the program
from the network and begin functioning normally
Replacing Damaged Modules
If a circuit cannot be controlled via the network or you wish to test the output channels manually the channel can be placed into a manual over-ride position
• Remove the cover from the OI
• Locate the channel you wish to bypass
• Remove the fuse from its ”Normal” position
• Place the fuse in the “Bypass” position
This will provide a complete mechanical bypass of the module
Note: It is important you ensure the fuse rating is appropriately rated
before putting the circuit into bypass
Warning. Bypassing can cause a potential ignition source. Ensure surrounding area is free of flammable/explosive gasses and vapors
Manual Circuit Bypass