Epson RC620 Manual page 26

2. Installation
Communications Power Supply
DeviceNet supplies 24V DC communications power to each node via 5-wire cables. You
can install the communications power supply at any location in the DeviceNet network.
Although the power can be shared to the node internal circuit power supply and I/O power
supply, it is recommended to use a dedicated communications power supply.
Shield Ground of Signal Wire
Ground the DeviceNet network at one point with 100 Ω or less.
As a noise countermeasure, you can leave the network ungrounded.
For details, refer to 4. Trouble shooting.
Maximum Network Length (Maximum Trunk Length)
The maximum network length is the longest distance either between terminating resistors
or between the two most distant nodes on the network.
Terminating
Resistor
The maximum network length is determined by the type of cable and the baud rate.
Baud Rate
Both Thick Cable and Thin Cable can be combined and used for trunk lines. In this case,
the maximum network length is calculated using the following formulas.
Baud Rate
16
The longest distance is the maximum network length.
Trunk Line
500 kbps
250 kbps
125 kbps
Thick Cable Length + Thin Cable Length ≤ 100m
500 kbps
Thick Cable Length + 2.5 × Thin Cable Length ≤ 250m
250 kbps
Thick Cable Length + 5.0 × Thin Cable Length ≤ 500m
125 kbps
Terminating
Resistor
Maximum Network Length
Thick Cable
100 m
250 m
500 m
Maximum Network Length
Thin Cable
100 m
100 m
100 m
RC620 Option Fieldbus I/O Rev.8