Check System Design - Parker H Series Installation & Service Instructions Manual

Check System Design

Table 5.1 Troubleshooting your system design
You can avoid many network problems by verifying that you have properly
designed your network. Begin by walking the physical network, and making a
sketch of your network layout. Then follow the checklist below.
check
number of nodes
cumulative drop line length
individual drop line length
branched drop line length
total trunk length
termination resistors
power supply cable
power cable to the trunk line
power supply cable
V- and shield wires
earth ground wire
CAN_L and CAN_H to shield
and/or V- wires
total current load
trunk and drop line currents
voltage at middle and ends of
network
lead dress at junction boxes
connectors
glands
glands
nodes
physical media (prior to applying
power)
physical media
Correct and Prevent Network Problems
to ensure that
you do not exceed the recommended maximum of 64 nodes. The practical limit
of DeviceNet nodes may be 61 devices, since you should allow one node each
for the scanner, the communication interface module, and an open node at
node 63.
you do not exceed the recommended maximum
you do not exceed the recommended maximum of 6m (20ft)
you do not exceed the recommended maximum
you do not exceed the recommended maximum
the trunk line is terminated at both ends with a 121Ω, 1%, 1/4W or larger
resistor
you are using the proper cable length and gauge
you are using the proper cable size and length
you do not exceed recommended electrical noise levels. Use an oscilloscope or
power disturbance analyzer to spot-check the cabling
these wires are properly connected and grounded. Break the shield to V-
connection at the power supply and use an ohmmeter to verify resistance is
less than 1MΩ with 24V dc removed.
you are using the proper length and gauge
no shorts are present. Use an ohmmeter to verify resistance is less than 1MΩ.
the current load does not exceed the power supply rating
you do not exceed recommended current limits
voltage measures higher than 11V dc but lower than 25V dc. If voltage falls
below 15V dc, a common mode problem may exist on the network. Refer to
Chapter 4 of this manual for more information.
you have made proper connections
connectors are screwed together tightly
glands are screwed together tightly
there is no foreign material (e.g., electrical tape, RTV sealant) in gland
nodes do not contact extremely hot or cold surfaces
there are no loose wires or coupling nuts
no opens or shorts are present.
Publication DNET-UM072C-EN-P - July 2004
5-5