System Tolerance Section 3 Installation
72 9ARD000015-600
System Tolerance
It is possible to make performance trade-offs and meet the DeviceNet requirements
by using the stack up limits listed in Table 57. The maximum system voltage
tolerance for DeviceNet is 24 volts +/- 4.0%. Table 57 lists the allocated tolerance
budget.
Avoiding Errors
ODVA suggests the following steps to minimize the number of design and
construction errors that could be encountered while configuring power on the
network:
• Execute the calculations suggested in the section Configuring Network Power
on page 63 to prevent network overloading.
• To verify accurate configuration, measure the voltage once the network is
constructed. A minimum of 11 volts is required at a node and the maximum
voltage drop (from V+ to V-) of 10 V is permitted.
• Allow sufficient margin of error to correct configuration problems without
damaging the network.
• For heavily loaded multiple supplies, turn on all supplies simultaneously to
prevent overloading fuses or make sure that unpowered sections are
disconnected from the rest of the network.
Table 57. Recommended Stack Up Standard for DeviceNet
Specification Parameter
Initial Power Supply Setting 1.0%
Line Regulation 0.3%
Load Regulation 0.3%
Temperature Drift 0.6% total
Schottky Diode Drop 0.75%
Time Drift 1.05%
Total Stack Up 4.0%
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