
B-64044EN/01 CONNECTION 1.CONNECTING THE DeviceNet
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1.7 POWER SUPPLY FOR COMMUNICATION
In DeviceNet, a power supply is required for communication. The
power supply must satisfy the following specifications and its AC
input and DC output must be insulated. The power supply must have
a capacity greater than the sum of power consumption of all nodes to
which power is supplied.
Specifications of a power supply for communication
Item Specification
Output voltage 24VDC±1%
Output current 16A or less
Input fluctuation Max. 0.3%
Load fluctuation Max. 0.3%
Effect of ambient
temperature
Max. 0.03%/°C
Output ripple 250mVp-p
Output side capacity Max. 7000µF
Ambient temperature Use:0 to 58°C
Storage:-40 to 85
°C
Instantaneous maximum
output current
Less than 65 A (peak)
Protection against
overvoltage
Enabled
Protection against
overcurrent
Enabled (maximum current 125
%)
Startup time 250 ms until 5% of the final output current is
achieved
Overshoot at startup
Max.0.2
%
Insulation Between output and AC power and between
output and cabinet ground
Complying standard
Required:
UL
Recommended:FCC Class B, CSA, TUV, VDE
Ambient humidity 30 to 90% (non-condensing)
Surge current 10%
Power must be supplied from the main line to nodes. The maximum
current capacity of a communication cable is 8 A for thick-wire cables
or 3 A for thin-wire cables.
The power supply for communication can be connected in various
layouts depending on the power requirement of the user.
The current capacity of a branch line varies with the branch line length.
The maximum power capacity of a branch line is reduced as the
branch length increases. This is the same when either a thick-wire
cable or a thin-wire cable is used. The capacity of current "I" that
can pass through one branch line (sum of current used for each branch
line) can be obtained with the following expression.
I = 4.57/L I: Allowable current (A)
L: Branch length (m)