Bus/Hardwired Mode Selection; Brief Devicenet Description; Network Cable; Terminator - Emerson Keystone OM11 Installation And Maintenance Instructions Manual

Keystone OM11 - EPI2 DEvIcENEt INtErfacE
InstallatIon and maIntenance InstructIons

6.3 bus/hardwired mode selection

the DeviceNet interface manages the bus/
hardwired mode selection by means of the
input terminal indicated with HW MODE. the
physical input accepts from 24 to 125 v Dc
or ac, polarity insensitive. When the input is
left unconnected or no voltage is applied, the
actuator is under bus control from which is
possible to send commands and read status.
When an appropriate voltage is applied to the
HW MODE input, the actuator turns under
Hardwired control. In this condition the bus can
only read actuator status while the actuator
follows the hardwired open and close controls
connected to the terminal board. for further
details see the relevant wiring diagram and
the user's manual: EPI2 Quarter-turn Electric
actuator IOM.

7 brIef deVIcenet descrIptIon

DeviceNet is a low-level network that provides
connection between industrial field devices
(sensors and actuators) and higher-level
devices (controllers). DeviceNet uses caN
(controller area Network) for its datalink layer,
and cIP (common Industrial Protocol) for the
upper layers of the network. the major physical
and media characteristics of the DeviceNet are:
• trunk-line / drop-line topology of the
network.
TR
Drop
PLc
DeviceNet scanner
Power tap
term.
DeviceNet
Power supply
caN v+
caN H
Shield
caN L
caN v-
• Support for up to 64 devices in a network
(i.e. 1 master and 63 EPI2 actuators).
• Node removal without altering the network
behavior.
• Support of both network-powered and self-
powered devices on the same network.
• Wiring error protection.
• Selectable data rate of 125 k baud, 250 k
baud and 500 k baud.
data
rate
125 k baud 500 meters
250 k baud 250 meters
500 k baud 100 meters
• adjustable power configuration to meet
individual application needs.
• High current capability (up to 8 a at 24 v Dc).
• Operation with off-the-shelf power supplies.
• available power taps that allow the
connection of several power suppliers.
• Build-in overload protection.
• controller area Network (caN) technology for
Media access control and Physical Signalling.

7.1 network cable

to obtain the expected performances from
the communication network the suitable cable
must be utilized. DeviceNet requires a specific
cable composed of a Power pair, a Data Pair
and a shield with drain wire. DeviceNet defines
different cables to be used in the different parts
of the network:
trunk
tap
trunk drop length
distance Maximum cumulative
6 meters 156 meters
6 meters 78 meters
6 meters 39 meters
tap tap
• in the trunk line is normally used the thick
cable.
E.g. BELDEN 3082a:
1 pair 15 aWg 19x28 tinned copper -
Power pair
1 pair 18 aWg 19x30 tinned copper -
Data pair inner shield 100% coverage
• in the drop line is normally used the thick
cable. e.g. BELDEN 3084a
E.g. BELDEN 3084a:
1 pair 22 aWg 19x34 tinned copper -
Power pair
1 pair 24 aWg 19x36 tinned copper -
Data pair inner shield 100% coverage

7.2 terminator

the DeviceNet network must be terminated to
each end of the main trunk line with a 120 ohm
resistor across caN_H and caN_L data line.
TR
term.
8