Automation Direct T1K-DEVNETS, User Manual

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Getting Started
Installation and
Safety Guidelines
1–4
Getting Started
Introduction to DeviceNet
DeviceNet is a low-level network designed to connect factory-floor devices to control
systems. There are a host of manufacturers of DeviceNet products, offering an array
of products including sensors, motor drives and starters, PLCs, pushbuttons,
remote I/O systems, etc.
Here are some DeviceNet concepts you may find helpful.
•
DeviceNet supports various communication structures including Peer to
Peer, Multi-master and Master/Slave.
The T1K–DEVNETS uses the
predefined Master/Slave connection.
•
DeviceNet has two types of messaging: Explicit Messaging and I/O
Messaging.
•
Explicit Messaging is low priority, not time-critical and usually
for configuration/diagnostic purposes.
•
I/O Messaging is time-critical and high priority
for I/O data transfer. I/O Messaging comes in four types:
•
Strobed
•
Polled (The T1K–DEVNETS only supports Polled.)
•
Change of State (or COS)
•
Cyclic
•
A single DeviceNet network is limited to 64 nodes. A node can be a
single-bit device, such as a limit switch, or a remote I/O slave with
several I/O modules, such as the T1K–DEVNETS. The Master
(Scanner) is usually assigned to node address 0, and many Slave
devices have a factory default node address of 63.
•
DeviceNet has the following data rates (with maximum bus lengths):
•
125 kbps (bus length = 500m max.)
•
250 kbps (bus length = 250m max.)
•
500 kbps (bus length = 100m max.)
•
The 24V DeviceNet power supply must be grounded at only one point.
The V– terminal must be tied to Protective Earth Ground at the power
supply only.
The DeviceNet standard is maintained by the ODVA (Open DeviceNet Vendor
Association, Inc.). Contact the ODVA for detailed information about DeviceNet.
Open DeviceNet Vendor Association, Inc.
20423 State Road 7
Suite 499
Boca Raton, FL 33498
Phone: (954) 340–5412
Fax: (954) 340–5413
Internet: www.odva.org
Email: odva@powerinternet.com
DeviceNet
Concepts
The ODVA