Installation manual

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Network Grounding:
The DeviceNet cable must by grounded at only one location. This should be done closest
to the center of the network. Connect the network Shield and Drain wire to an earth
ground using #8 AWG wire up to a maximum 3m ( 10Ft ) in length.Also connect the V-
conductor ( Black Wire) of the network trunk cable and the DC ground of the power
supply to this ground connection.
Power Supply Discussion:
DeviceNet requires 24VDC. Use a power supply rated 24VDC (+/- 1% ). Make sure the
power supply has it's own current limit protection. Provide fuse protection for each
segment of the cable system. DeviceNet requires a power supply to have a rise time of
less then 250mS to within 5% of its rated output voltage. The power supply must be sized
correctly to provide each device with its required power.
1. The thin wire trunk line can only handle 3 amps and the thick wire trunk line can
physically handle 8 amps. However, in North America the current is limited to 4 amps.
Multiple power supplies can be installed on a DeviceNet network, but no section of cable
should have more current flowing than the appropriate rating. An important note is that
when putting multiple power supplies on a network; break the Red V+ wire between the
power supplies. This effectively isolates the power supplies from each other.
2. Common mode voltage can sometimes be an issue on DeviceNet networks which have
trunk lines that are extra long and/or have devices on them, drawing large currents at
longer distances. If the voltage on the Black V- wire ever gets more than 4.65 volts
different from one point of the network to another, then communication problems could
occur. On an existing network, if the voltage between the Red V+ wire and the Black V-
wire ever gets below 15 volts, then common mode voltage could be adversely affecting
network communications. Adding an additional power supply or moving an existing
power supply closer to the heavier current loads will normally cure common mode
voltage problems.
Important:
It is recommended that the DeviceNet power supply should be used to power
the DeviceNet network only. When multiple power supplies are required, verify that the
V+ connection is broken between the supplies. Please refer to the " DeviceNet Planning
and Installation Manual " for more specific installation procedures.
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