Allen-Bradley 1769-SDN, Installation Instructions Manual, Page: 54 / 68

54 Rockwell Automation Publication DNET-IN001B-EN-P - January 2012
Appendix A 1756 DeviceNet Status Indicators and Data Structures
Status Structure
The controller receives status information concerning the 1756-DNB scanner
module’s ability to exchange DeviceNet messages with other nodes by reading
from the status structure in the 1756-DNB scanner module. The scanner module
periodically updates the contents of the status structure and copies its contents to
the controller. The status structure consists of several tables. The bit position of
each of the 64-bits that make up a given status table directly corresponds to the
node address of a device.
The status structure consists of these data elements.
Status Structure Element Description Data
Type DINTS
ScanCounter Counter incremented each I/O scan 32-bit 10
DeviceFailureRegister Device failed bit table; 1 = failed 64-bit
AutoverifyFailureRegister Device I/O size does not match scanner’s
internal table; 1 = mismatch 64-bit
DeviceIdleRegister Device is idle bit table; 1 = idle 64-bit
ActiveNodeRegister Node online bit table; 1 = online 64-bit
StatusDisplay ASCII representation of scanner
alphanumeric display 4-byte
ScannerDeviceStatus Scanner device status 4-byte
binary 11
ScannerAddress DeviceNet address of1756- DNB scanner
module 8-bit
binary
ScannerStatus Status of 1756-DNB scanner module 8-bit
binary
ScrollingDeviceAddress Scrolls through DeviceNet nodes once
per second by address and status; 0 = no
faults 8-bit
binary
ScrollingDeviceStatus 8-bit
binary
ReservedArray Future expansion (20 bytes) 20 x 8-bit 16
DeviceStatus DeviceNet node status array, byte per
device 64 x 8-bit 24/32