
1.CONNECTING DeviceNet FUNCTIONS CONNECTION B-63404EN/03
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1.8 COMMUNICATIONS POWER SUPPLY
With DeviceNet, power must be supplied for communications. Use a
power supply that satisfies the specifications shown in the table below
and that has insulated AC input and DC output as the communications
power supply. Also, select a communications power supply having
margin in its current capacity greater than the total current
consumption of all nodes to which power is to be supplied.
Communications Power Supply Specifications
Item Specifications
Output voltage 24VDC ± 1%
Output current 16 A max.
Input fluctuation Max. 0.3%
Load fluctuation Max. 0.3%
Influence of ambient temperature Max. 0.03%/°C
Output ripple 250mVp-p
Output side capacity Max. 7000 µF
Ambient temperature During operation : 0 to 50°C
During storage : -40 to +85°C
Inrush Current Limit Less than 65 A (peak)
Protection against overvoltage Provided
Protection against overcurrent Provided (max. current 125%)
Startup time 250 ms up to 5% value of final output
voltage
Overshoot at startup Max. 0.2%
Insulation Across output and AC power supply,
and output and housing
Compliant standards Necessary : UL
Recommended : FCC Class, B, CSA
TUV, VDE
Ambient humidity 30 to 90% (no condensation allowed)
Surge current Max. 10%
Be sure to supply power from the trunk down to the branches. The
maximum current capacity of the communications cable is 8A on
thick cables and 3A on thin cables.
The communications power supply is connected in various forms
depending on the user's power supply requirements.
The current capacity of the branch varies according to the branch
length. The longer the branch, the smaller the branch's maximum
current capacity becomes. The same applies if the cable used as the
branch is thick cable or thin cable. Calculate the possible current
capacity (I) on a single branch (the total current that is consumed on
each branch) according to the following expression:
I = 4.57/L I: Allowable current (A)
L: Branch length (m)