CDN36X User Manual
revision 1.30
and 0x03 (ETX). You must use the RSNetworx
™
Class Instance Editor (Set Attribute Single
command) to write a Short_String attribute value.
Packet Timeout –
Required for
Timeout Mode
. Defines the timeout period between received
bytes that indicates the end of a message packet (1-255 milliseconds).
Packet Length –
Required for
Length Mode
. Defines the message packet size (1-128 bytes).
Serial Status –
Serial transmitter and receiver error bits. To clear an error, you must either reset
the gateway or clear the error bit using a SET_ATTRIBUTE explicit message command.
Byte Swap –
Defines if CDN36X gateway swaps I/O message bytes. When disabled, the
CDN36X I/O messages are mapped into the PLC DeviceNet Scanner module memory in low-
byte / high byte format. Many PLC processors use word-aligned data tables, so working with
ASCII strings in a low byte / high byte format is difficult. By enabling the CDN36X byte swap
feature, the gateway automatically swaps each pair of contiguous bytes in the I/O messages.
This allows you to send output message data in high byte / low byte format, and receive input
message data in high byte / low byte format.
The following example shows how the CDN36X byte-swap feature modifies the input bytes in a
DeviceNet I/O Response Message.
Normal Format:
TX Ack Byte
RX Toggle Byte
SRO1 RXData 1
SRO1 RXData 2
SROx RXData N
SROx RXData N+1
……
Swapped Format:
The following example shows how the CDN36X byte-swap feature interprets the output bytes in
a DeviceNet I/O Command Message.
Normal Format:
Swapped Format:
RS422 Mode
– CDN367 only. Selects between RS422 4-wire or RS485 2-wire operation.
I/O Produce Size –
Read-only attribute is the number of input bytes sent in an I/O Response
Message. Gateway calculates based on enabled
Serial Receive Object
Instances’
Data
Size
.
I/O Consume Size –
Read-only attribute is the number of output bytes expected in an I/O
Command Message. Gateway calculates based on enabled
Serial Transmit Object
Instances’
Data Size
.
TX Toggle Byte
RX Ack Byte
STO1 TXData 1
STO1 TXData 2
STOx TXData N
STOx TXData N+1
……
RX Ack Byte
TX Toggle Byte
STO1 TXData 2
STO1 TXData 1
STOx TXData N+1
STOx TXData N
……
RX Toggle Byte
TX Ack Byte
SRO RXData2
SRO RXData1
SROx RXData N+1
SROx RXData N
……
MKS Instruments, Inc.
D.I.P. Products Group
33