Introduction to DeviceNet

1
Chapter 11

• Introduction to DeviceNet

2
DeviceNet Purpose

• Open network
• Link low-level devices to PLCs
• Sensors
• Pushbutton stations
• Distributed I/O blocks
• Intelligent motor started overloads
• Variable frequency drives

3
DeviceNet Open Network

• Open network
• Network devices (nodes) can be purchased from
  many different vendors
• Network managed by Open DeviceNet Vendors
  Association (ODVA)
• ODVA.ORG

4
DeviceNet Advantage

• Save wiring costs
• Rather than run power wires separately to each
  device
• Rather than run signal wires from each field
  device separately back to PLC, I/O module connect
  devices directly to a network
• One cable with four wires
• Two power wires
• Two signal wires

5
Field Devices More Intelligent

• Traditional systems
• A photo switch counting pieces as they pass on a
  conveyer was wired directly into an input module.
• Counter programmed on ladder to track parts
  count
• Counter done bit triggered output point to
  control field action

6
DeviceNet Advantage

• Many DeviceNet devices are intelligent.
• Photo switch has counters and timers incorporated
  into sensor.
• PLC does not need to have timer or counter on
  ladder.
• When timer or counter is done, the action is
  carried out through RSNetWorx for DeviceNet
  software to trigger field device across the
  network.

7
DeviceNet Components

• PLC with DeviceNet scanner
• RSNetWorx software for DeviceNet
• Trunk line
• Drop lines
• Nodes
• Minimum one power supply
• Two 121-ohm ¼-watt termination resistors
• Up to 64 nodes

8
DeviceNet Network Example
Cable to open-style connector on network PLC
scanner
Prox switch and cable
Stack light
KwikLink cable
Power supply
Termination resistor
ArmorBlock maximum 4 I/O points
Termination resistor
Insulation displacement connector
Open-style connection for power supply
CompactBlock I/O module
RightSight photo sensor
9
Sample of Some DeviceNet Media Components
Thick round drop line cable
Device port
T-port
KwikLink drop line cable
KwikLink flat trunk line cable
KwikLink flat trunk line cable insulation
displacement connector
DeviceLink
10
DeviceNet Cabling

• Thick round
• Thin round
• KwikLink cable
• Special-use cable
• Open-style connectors

11
Thick Round Cable

• Used for trunk line
• T-ports used to connect from trunk line to drop
  lines

12
Thin Round Cable

• Typically used for drop lines
• Can be used for trunk in short networks with low
  current requirements

13
KwikLink DeviceNet Connection
Insulation displacement connector
KwikLink flat cable
14
Insulation Displacement Connection

• For non-wash down
• Typical usage conveyor lines
• Mount on inside rail of conveyor
• No conduit needed
• Easy installation of new nodes
• No minimum spacing

15
DevicePort

• Passive 4- or 8-point taps
• Connected to trunk line by drop line
• Previous slide showed an 8-point DevicePort
• Nodes connected to DevicePort by drop lines

16
T-port

• Used to connect drop line to trunk line
• Drop line connected to DevicePort and then on to
  multiple nodes
• Drop line connected directly to node
• Maximum drop line length 20 feet

17
DeviceLink

• Adapter to interface non-DeviceNet devices to
  network
• 2- or 3-wire 24-V sensors
• Mechanical limit switches
• Any non-DeviceNet device with relay contacts
• One required for each non-DeviceNet node

18
Additional Media

• Refer to the DeviceNet Media catalog for a
  complete listing of available products.

19
Maximum Trunk Line Length (1 of 2)

• Maximum cable distance between any two nodes
• Not necessarily actual length of backbone
• Maximum length determined by cable type and baud
  rate

20
Maximum Trunk Line Length (2 of 2)
21
Trunk Line Calculation One
Node number
22
Example One

• Left terminating resistor to node 1 is 12 feet.
• Drop line node 1 is 2 feet.
• Right terminating resistor to node 12 is also 12
  feet.
• Node 12 drop line is 2 feet.
• From node 1 drop line to node 12 drop line is 800
  feet.

23
Trunk Line Calculation (1 of 2)

• For this example, trunk line length is maximum
  length of cable between terminating resistors.

24
Trunk Line Calculation (2 of 2)

• 12 800 12 824 feet
• Refer to table for maximum baud rate of network.

25
Maximum Trunk Line Length
Trunk line length is over 820 feet so maximum
baud rate for this network is 125 K.
26
Trunk Line Calculation Two

27
Example Two

• Left terminating resistor to node 1 drop line is
  20 feet.
• Node 1 drop line is 6 feet.
• Right terminating resistor to node 12 drop line
  is 2 feet.
• Node 12 drop line is 8 feet.
• Trunk line from node 12 drop to node 14 drop line
  is 3 feet.
• Node 14 drop line is 12 feet.
• Node 1 trunk line to node 14 is 300 feet.

28
Trunk Line Calculation

• For this example, trunk line length is maximum
  length of cable between any two nodes or
  terminating resistors.
• Assume round thick trunk line.
• Look at network again.

29
Trunk Line Calculation Two (1 of 2)
30
Trunk Line Calculation Two (2 of 2)

• The longest cable distance is between the left
  terminating resistor and node 14.
• For this example, the distance between
  terminating resistors would not be the correct
  calculation.
• 20 300 12 332 feet
• Refer to table for maximum baud rate of network.

31
Maximum Trunk Line Length (1 of 3)
Trunk line length is over 328 feet so maximum
baud rate for this network is either125 K or 250
k.
32
Maximum Trunk Line Length (2 of 3)

• The rule is to go back 20 feet from the
  termination resistors and see if there is a drop
  line that is longer.
• If a drop is longer, then it must be included in
  the trunk line calculation.
• Remember maximum drop line length is 20 feet.

33
Maximum Trunk Line Length (3 of 3)

• Terminating resistor and node 00 is 3 feet.
• Node 00 and node 1 is 4 feet.
• Trunk line to node 7 is 15 feet.
• 15 foot drop is longer than 3 4 for trunk.

34
Cumulative Drop Line Length (1 of 2)

• Sum of all drop lines
• Maximum drop line length to any one node
• 20 feet
• Cumulative drop line length also determines
  network baud rate

35
Cumulative Drop Line Length (2 of 2)
Text figure 11-30
36
Total All Drop Line Lengths (1 of 2)
37
Total All Drop Line Lengths (2 of 2)

• Cumulative length is 131 feet.
• Nodes 10, 13, and 14 exceed the 20-foot maximum
  drop to any 1 node.
• Shorten up cable.
• Cumulative drop line length is now 127 feet.
• Refer to the table for maximum baud rate for
  network.

38
Cumulative Drop Line Length
39
Power Calculations

• Add up total device current
• Determine trunk line length
• Cable type
• How many power supplies and where mounted
• Look up tables for power allowed on network
• Full calculation method available for additional
  accuracy

40
Common Problems With DeviceNet Networks (1 of 2)

• Improper installation
• Trunk line length correct?
• Cumulative drop line length correct?
• Power supply proper size?
• Overdriving network with too much information
  flow?
• Refer to DeviceNet Cable System Planning and
  Installation Manual from Rockwell Automation Web
  site.

41
Common Problems With DeviceNet Networks (2 of 2)

• Network modification after installation
• Trunk line length recalculated?
• Cumulative drop line length recalculated?
• Power supply recalculated?
• Overdriving network with too much information
  flow?

42
DeviceNet Interface
43
FlexLogix PLC DeviceNet Daughter Card
DeviceNet open-style cable connection point
Set baud rate
Status LEDs
Set interface cards node
44
CompactLogix DeviceNet Scanner
DeviceNet scanner Open-style cable connection
CompactLogix processor
CompactLogix is a member of the ControlLogix
family.
45
ControlLogix Modular Interface
1756-DNB

• ControlLogix modular chassis interface module
• 1756-DNB
• DeviceNet bridge module

Information window
Status LEDs
Open-style network connection
46
Example of Rockwell Automation PLC DeviceNet
Interface Modules

• SLC 500 DeviceNet scanner
• 1747-SDN
• PLC 5 DeviceNet scanner
• 1771-SDN

47
Example of General Electric PLC DeviceNet
Interface Modules

• Series 90-30 PLCs
• DeviceNet master module
• IC693DNM200
• VersaMax PLC
• Remote I/O DeviceNet network interface
• IC200DB1001

48
Personal Computer DeviceNet Interface

• Computer type determines interface needed.
• Notebook uses PCMCIA such as a Rockwell
  Automation 1784-PCD.
• Desktop or industrial computer would require a
  DeviceNet 1784-expansion card.
• Computer with serial port could use Rockwell
  Automation 1770-KFD interface box.

49
1770-KFD Interface
Desktop or notebook computer with serial port
SLC 500 1747-SDN
Interface cable plug
Open-style connector to DeviceNet network
Interface cable
1770-KFD
KFD to serial port interface cable
50
1784-PCD Card
51
Use ControlLogix PLC as a Bridge (1 of 2)

• Most popular interface to PLC for upload,
  download, on-line editing is Ethernet
• Ethernet interface card in ControlLogix
  chassis(1756- ENBT)
• A 1756-DNB or DeviceNet bridge module in
  ControlLogix chassis to communicate with DeviceNet

52
Use ControlLogix PLC as a Bridge (1 of 2)

• Use RSLinx Ethernet driver to get to Ethernet
  interface module
• Bridge across ControlLogix backplane to DeviceNet
  Bridge module (1756-DNB)
• Out DNB to DeviceNet network
• No separate DeviceNet interface required

53
RSNetWorx Software

• RSNetworx for DeviceNet software
• Set up network
• Map data flowing on network
• Program, monitor, or modify device parameters

54
RSNetWorx for DeviceNet
55
RSNetWorx View of DeviceNet
Network scanner
Drop line
Termination resistor
Termination resistor
Node address
Trunk line
Device or node on network
Power supply not shown in RSNetWorx
56
DeviceNet Scan List

• RSNetWorx software
• Scan List is part of scanner properties.
• Any device that is on the network that is to be
  scanned by the PLC scanner must be in the Scan
  List.
• Network devices are not mapped until placed in
  the Scan List by programmer.
• Auto mapping
• Manual mapping

57
DeviceNet PLC Scanner Properties
Scan List tab
ControlLogix DNB scanner properties screen
Scan List
Add or remove single device to or from Scan List
Add or remove all devices to or from Scan List
Electronic keying
Auto map devices when add to scan list
58
Available Devices on Network

• When going on-line with a network scanner, like a
  1756-DNB, scanner will recognize devices
  currently present on network.
• These devices or nodes will be listed in the
  Available Devices view.
• These devices are not in the scan list at this
  time.

59
Auto Map Devices When Add to Scan List

• Do you want the device(s) to be auto-mapped when
  added to the scan list?
• If Automap is selected, you have no control of
  how devices are mapped.
• If you uncheck Automap, then devices can be
  manually mapped by the programmer.

60
Electronic Keying

• How close does a replacement device have to be to
  the original when replaced?
• Device type
• Vendor
• Product code
• Major revision
• Minor revision
• Minor revision or higher

61
DeviceNet Data Mapping

• ControlLogix

62
ControlLogix 1756-DNB Mapping
Input tab
Scanner properties
Click here to unmap a device.
Input devices in Scan List
Unused processor memory. Can be manually mapped
later.
Data mapping for each node
ControlLogix processor tags or addresses where
data is mapped.
63
DeviceNet Data Mapping

• ControlLogix is a 32-bit PLC.
• All tags will be either 32 bits wide or a
• Word, called an integer (INT) which is16 bits
• Byte, called a short integer (SINT) which is 8
  bits
• Minimum memory allocation for any DeviceNet
  device is a SINT.
• Node 6 is a bulletin 160 Allen-Bradley Drive.
• Drive has two words of data.
• Drive status information as single bits
• Drive speed feedback represented as 0 to 32767

64
ControlLogix Input Mapping
32 Bits
16 Bits
31
0
7
8
15
16
Node 3 Series 9000 Photo Electric Sensor mapping
ControlLogix Tags
Node 6 Drive Input Status word
Node 6 Drives Speed Feedback word
Node 4 Series 9000 Photo Electric Sensor mapping
65
ControlLogix Processor Data Mapping or Tags (1
of 2)

• Node 6 is Bulletin 160, the variable frequency
  drive
• Status bits mapped as upper word of
  Local1I.Data2.
• Drive Speed Feedback word is mapped as the lower
  word of Local1I.Data3.

66
ControlLogix Processor Data Mapping or Tags (2
of 2)

• Node 4 is a Series 9000 Photo Switch mapped as
  the upper byte of the lower word at
  Local1.I.Data2.
• Node 3 is a Series 9000 Photo Switch mapped as
  the lower byte of the lower word at
  Local1.I.Data2.

67
DeviceNet Data Mapping

• SLC 500

68
DeviceNet Data Mapping

• SLC 500 and PLC 5 are 16-bit computers.
• All data will either be a 16-bit word or one
  byte.
• Minimum memory allocation for any DeviceNet
  device is a byte.
• Node 6 is a Bulletin 160 Allen-Bradley Drive.
• Drive has two words of data.
• Drive Command information as single bits
• Drive Speed Command represented as 0 to 32767

69
SLC 500 Output Data Mapping
1747-SDN properties view
Output mapping tab
Click here to unmap selected device
Output devices in Scan List
SLC 500 Output Status Table where data is
coming from
Two words or 8 bytes currently mapped for drive
at node 6
70
SLC 500 Processor Data Mapping

• Node 6 is Bulletin 160, the variable frequency
  drive
• Drive Command bits word is mapped as O1.2.
• Drive Speed Command word is mapped as O1.3.

71
Node 2 Output Mapping

• Node 8 is a Rockwell Automation 1792D compact
  block output module.
• This compact block has four outputs.
• Output data from SLC 500 mapped to lower byte of
  O1.6.
• Currently upper byte of O1.6 is available for
  another device.

72
DeviceNet Nodes General Properties
73

• Right click on device on RSNetWorx screen.
• General Properties screen is displayed.
• Display I/O data
• Display, monitor, or modify devices parameters
• View electronic data sheet (EDS file)

74
General Properties
EDS tab
Parameters tab
Identifies this device
Current node address. Node address can be
changed here.
Devices identity
Numbers used to identify EDS file
75
Device Parameters
Monitor a single parameter or all
Device
Parameters tab
Icons for uploading or downloading to device
Lock identifies read-only parameters
Click here to monitor parameter
Parameter number
Current value of parameter
76
Parameter Editing
Select parameter to edit
Options drop-down box
Select
77
Electronic Data Sheets

• EDS Files

78
Electronic Data Sheets

• Typically referred to as EDS files
• EDS files contain information regarding the
  personality of the device.
• Correct EDS file must reside in the device before
  it can be a working part of the network.
• EDS file must be the same firmware level as the
  device.

79
If EDS File Is Not Current

• Go to manufacturers Web site and download
  correct file.
• Go to ODVA.ORG site and download correct file.
• EDS file numbers represented in Hex.
• Use EDS Wizard to update or register the network
  device.

80
EDS Wizard
Updating a network Devices EDS file is
to register the file.
Click next to continue.
81
Register EDS File
After download, browse for file on you computer.
How many files to register
EDS file name represented in Hex
Click next to continue registration.
82
Determine EDS File Name

• After downloading EDS file, the file name is
  represented in Hex.
• To determine EDS file to use when registering
  file
• Must know Hex
• Construct file number from RSNetWorx general
  properties page

83
Convert General Properties Page Device Identity
to Hex
1 0001
6 0006
43 002B
1.004 0100
84
Select Correct EDS File
85
Select Correct EDS File