Echelon DM-21 Device Manager - Manual (Page 98)

A-2 Troubleshooting
Troubleshooting the DM-20/21 Hardware
Power LED is extinguished
• The power supply providing power to the module may have lost primary
power. Check the power supply output for the presence of power.
• The power wiring may not be correctly connected to the module. Use a volt
meter to check for power on Base Plate power terminals.
• The input voltage may be too low due to an excessive load on the power
supply providing power to the module, excessively long power cabling, or
shorted power wiring. Use a volt meter to check for the correct voltage level
on the base plate power terminals. Correct cabling length if too long. Repair
faulty power cable.
• The Device Manager firmware version may be a down-revision prior to 2.0.
An error in the pre-2.0 firmware prevented the power LED from illuminating.
The Service LED is flashing
The module is unconfigured. This is the normal state of a new module. The
module is commissioned when a database is downloaded into it by the Device
Manager Loading Wizard.
The Service LED is illuminated
The module is applicationless and has lost its application software program. The
module must be reloaded by the Device Manager Loading Wizard. See Chapter 8
for more information.
No communication between the Device Manager and the network
• The network wiring may not be correctly connected to module.
• Network cabling may be shorted, open, or otherwise damaged. Use a
continuity meter to check cabling.
• One or more routers on the network may be not commissioned, not powered,
or otherwise not functioning correctly.
• A router may be installed with the incorrect router channel type.
Erratic or improper communication between the Device Manager and
the network
• The network wiring may not be securely connected to Base Plate terminals.
The optimum tightening torque for a Base Plate screw terminal is 4 lbs. in.
(0.5Nm) maximum.
• The Device Manager module may not be properly seated in the Base Plate.
Ensure that the module is pressed firmly into the Base Plate and secured
with suitable fixing screws.
• There may be improper or missing network termination. A free topology
TP/FT-10 channel requires one Model 44100 Terminator located anywhere on
the channel. A bus topology TP/FT-10 channel requires two Model 44101
terminators, one at each end of the bus.