CDN36X User Manual
revision 1.30
Chapter 3 – Theory of Operation
This chapter describes how the CDN36X gateway operates. You should have a working
knowledge of DeviceNet and asynchronous serial communications before continuing. The Open
DeviceNet Vendors Association (
www.odva.com
) is a good source for general DeviceNet
information. Refer to your serial device documentation for its protocol information.
Gateway Operation
The CDN36X gateway receives asynchronous serial messages over its serial channel, converts
them to data values, and returns the values as input data to the DeviceNet master. The gateway
receives output data from the DeviceNet master, converts them into serial messages, and
transmits the messages out its serial channel. The following diagram shows the major gateway
components.
Gateway Core
• microcontroller
• RAM
• Flash ROM
DC:DC Power Conversion
• 24VDC DeviceNet power input
• VDC for Core & DeviceNet channel
• isolated VDC for serial channel
DeviceNet Channel
• 24VDC power
• communications
Serial Channel
• c
• flow control
ommunications
5-pin male
micro connector
Male DB9
connector
Serial Stream Object
Serial Transmit Object
(up to 8 Instances)
Serial Receive Object
(up to 8 Instances)
Devicenet I/O Response
input data
serial
messages
DeviceNet Object
or Rotary Switches
DeviceNet I/O Command
output data
Configures the DeviceNet
interface baud rate and
MAC ID address.
Converts output data from
DeviceNet master to message
packet. Transmits message
packet out the serial channel.
Converts received message
packet to input data. Input
data returned to DeviceNet
master.
Configures the serial channel.
Scans channel for valid message
packets, which are passed to
Serial Receive Object instances.
MKS Instruments, Inc.
D.I.P. Products Group
9