5, DeviceNet I/O Image. Allen-Bradley 1769-SDN
Allen-Bradley 1769-SDN is a DeviceNet Scanner Module that provides a gateway between CompactLogix controllers and DeviceNet devices. It allows you to connect up to 64 DeviceNet slave devices and communicate with them using the RSNetWorx for DeviceNet software. The 1769-SDN is ideal for applications where you need to control a large number of devices, such as in a manufacturing or automation setting.
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SDN Input File
Chapter
5
DeviceNet I/O Image
This chapter describes the input and output data structure.
The following table describes what this chapter contains and where to find specific information.
For information about
See page
The 1769-SDN scanner module’s input image is configurable up to 246 words. The input image is broken up into two primary components, the status area and the input data area.
Table 5.1 Input Image
Name
Status Structure
Input Data Image
Size
66-words (fixed)
180-word array (configurable)
Word Offset
0 to 65
66 to 245
1
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5-2 DeviceNet I/O Image
Status Structure
The first area of the input image is the Status Structure and is
illustrated in Table 5.2. The status words are described in more detail
in the following sections
Table 5.2 Status Structure
Description
Scan Counter
Device Failure Array
Autoverify Failure Array
Slave Device Idle Array
Active Node Array
Reserved
(1)
Scanner Status
Reserved Array
Device Status Array
Module Status Register
Words
0 and 1
2 to 5
6 to 9
10 to 13
14 to 17
18 and 19
20 and 21
22 to 31
32 to 63
64 and 65
Data Type
2 words
64-bit array
64-bit array
64-bit array
64-bit array
4-byte array
4-byte array
20-byte array
64-byte array
2 words
(1)
DO NOT manipulate Reserved Bits. Doing so may interfere with future compatibility.
Scan Counter
This 32-bit unsigned value is incremented each time the DeviceNet network is scanned. The value will automatically roll over to zero and continue counting.
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DeviceNet I/O Image 5-3
Device Failure Array
These 64 bits provide status information for use in your control program. For each slave device owned by the scanner the user should monitor the respective bit within these four words. If a slave device faults, the bit that corresponds to that node address will be set (1). If a slave device is not faulted or returns from a faulted state to an operating state, the corresponding bit for that node will be cleared (0).
Table 5.3 Slave Device Status Information
Input Word
2
(1)
3
(2)
4
(3)
5
(4)
Bit 0 to Bit 15
Node 0 to Node 15
Node 16 to Node 31
Node 32 to Node 47
Node 48 to Node 63
Description
Bit ON (1) = Slave node faulted
Bit OFF (0) = Slave node not faulted
(1)
Bit 0 corresponds to Node 0, Bit 1 corresponds to Node 1 … Bit 15 corresponds to Node 15.
(2)
Bit 0 corresponds to Node 16, Bit 1 corresponds to Node 17 … Bit 15 corresponds to Node 31.
(3)
Bit 0 corresponds to Node 32, Bit 1 corresponds to Node 33 … Bit 15 corresponds to Node 47.
(4)
Bit 0 corresponds to Node 48, Bit 1 corresponds to Node 49 … Bit 15 corresponds to Node 63
Autoverify Failure Array
These four words allow the control program to monitor if a slave’s
Device Key and Size matches the Device Key and Size in the scanner.
A bit value of 0 (OFF) represents a configuration match, a bit value of
1 (ON) represents a mismatch.
ATTENTION
!
A value of 0 DOES NOT indicate that the slave has been brought online or is functional, only that there is a configuration match between the slave and the scanner.
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5-4 DeviceNet I/O Image
Table 5.4 Slave Device Configuration Comparison to Scanner Configuration
Input Word
6
(1)
7
(2)
8
(3)
9
(4)
Bit 0 to Bit 15
Node 0 to Node 15
Node 16 to Node 31
Node 32 to Node 47
Node 48 to Node 63
Description
Bit ON (1) = Slave node mismatch
Bit OFF (0) = Slave node match
(1)
Bit 0 corresponds to Node 0, Bit 1 corresponds to Node 1 … Bit 15 corresponds to Node 15.
(2)
Bit 0 corresponds to Node 16, Bit 1 corresponds to Node 17 … Bit 15 corresponds to Node 31.
(3)
Bit 0 corresponds to Node 32, Bit 1 corresponds to Node 33 … Bit 15 corresponds to Node 47.
(4)
Bit 0 corresponds to Node 48, Bit 1 corresponds to Node 49 … Bit 15 corresponds to Node 63
Slave Device Idle Array
The slave device idle array contains 64 bits of data. Each bit indicates the state of a slave device. A bit value of 0 represents a non-idle mode or that the slave is not present in the scanlist. A bit value of 1 represents idle mode where the slave node is present in the scanlist.
Table 5.5 Slave Device Status
Input Word
10
(1)
11
(2)
12
(3)
13
(4)
Bit 0 to Bit 15
Node 0 to Node 15
Node 16 to Node 31
Node 32 to Node 47
Node 48 to Node 63
Description
Bit ON (1) = idle
Bit OFF (0) = non-idle
(1)
Bit 0 corresponds to Node 0, Bit 1 corresponds to Node 1 … Bit 15 corresponds to Node 15.
(2)
Bit 0 corresponds to Node 16, Bit 1 corresponds to Node 17 … Bit 15 corresponds to Node 31.
(3)
Bit 0 corresponds to Node 32, Bit 1 corresponds to Node 33 … Bit 15 corresponds to Node 47.
(4)
Bit 0 corresponds to Node 48, Bit 1 corresponds to Node 49 … Bit 15 corresponds to Node 63
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DeviceNet I/O Image 5-5
Active Node Array
The Active Node array contains 64 bits of data that represents each slave node’s status. A slave node is considered active when it is present and enabled in the master’s scanlist. A bit value of 0 means
Not Active, a bit value of 1 means Active.
Table 5.6 Slave Node Status
Input Word Bit 0 to Bit 15
14
(1) Node 0 to Node 15
Node 16 to Node 31
15
(2)
16
(3) Node 32 to Node 47
17
(4) Node 48 to Node 63
Description
Bit ON (1) = Active node
Bit OFF (0) = Inactive node
(1)
Bit 0 corresponds to Node 0, Bit 1 corresponds to Node 1 … Bit 15 corresponds to Node 15.
(2)
Bit 0 corresponds to Node 16, Bit 1 corresponds to Node 17 … Bit 15 corresponds to Node 31.
(3)
Bit 0 corresponds to Node 32, Bit 1 corresponds to Node 33 … Bit 15 corresponds to Node 47.
(4)
Bit 0 corresponds to Node 48, Bit 1 corresponds to Node 49 … Bit 15 corresponds to Node 63
Scanner Status
The Scanner Device Status is a 4-byte array which contains the
information shown in Table 5.7.
Table 5.7 Scanner Device Status
Input Word
20
21
Bit
Description
(1)
0 to 7 (lower byte) Scanner Address in BCD
8 to 15 (upper byte) Scanner Status in BCD
0 to 7 (lower byte) Slave Device Address in BCD
8 to 15 (upper byte) Slave Device Status in BCD
(1)
Status codes are defined in Table 8.2 on page 8-3.
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5-6 DeviceNet I/O Image
Reserved Array
Table 5.8 Reserved Array
Input Word
22 to 31
Description
(1)
Always 0
(1)
DO NOT manipulate Reserved Bits. Doing so may interfere with future compatibility.
Device Status Array
The Device Status Array is a 64-byte array containing the information shown in the following table. Each byte indicates the status code of the scanner’s master and the slave devices.
Table 5.9 Device Status
Input Word
32
33
...
63
Bit
Description
(1)
0 to 7 (lower byte) Node 0 DeviceNet Status
8 to 15 (upper byte) Node 1 DeviceNet Status
0 to 7 (lower byte) Node 2 DeviceNet Status
8 to 15 (upper byte) Node 3 DeviceNet Status
...
...
0 to 7 (lower byte) Node 62 DeviceNet Status
8 to 15 (upper byte) Node 63 DeviceNet Status
(1)
Status codes are defined in Table 8.2 on page 8-3.
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DeviceNet I/O Image 5-7
Module Status Register
The scanner supports a 32-bit Module Status Register as shown below:
Table 5.10 Scanner Module Status Register
Input Word
64
Bit
0
1
2
Description
Run
Fault
Network Disable
Operation
Bit ON (1) = scanning I/O
Bit OFF (0) = halted
Bit ON (1) = faulted
Bit OFF (0) = not faulted
Bit ON (1) = disabled
Bit OFF (0) = not disabled
Bit ON (1) = failure
Bit OFF (0) = no failure
5
6
3
4
7
Device Failure
Autoverify Failure
Communication Failure
Duplicate Node Failure
DeviceNet Power Detect
65
8 to 15
0 to 15
Reserved
(1)
Reserved
Bit ON (1) = power
Bit OFF (0) = no power n/a n/a
(1)
DO NOT manipulate Reserved Bits. Doing so may interfere with future compatibility.
Input Data Image
The Input Data Image can be up to a 180-word array as shown below:
Table 5.11 Input Data Image
Word Offset
66 to 245
Description
DeviceNet Slave input and/or master output data
The Input Data Image is mapped using RSNetWorx for DeviceNet configuration software.
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5-8 DeviceNet I/O Image
SDN Output File
Output Array
The scanner supports up to 182 output words. This array is broken up into two distinct data segments.
Table 5.12 Output Array
Name
Module Command Array
Output Data Image
Size
2 words
180-word array
Word Offset
0 and 1
2 to 181
Module Command Array
The module command array is the primary control interface between your control program and the module.
Table 5.13 Module Command Array
Output
Word
0
Bit
0
Description Behavior
1
1
2
3
4
5 to 15
16 to 31
Run
Fault
This bit controls when the module scans its mapped slave devices. When set (1), the scanner will process I/O data as defined by its scanlist. To actually scan the network the
Fault and Disable Network command bits must be clear (0).
When set, the scanner’s I/O mode will be
Halt; messaging will still operate. The fault bit is primarily used to artificially set the slave devices into a fault state due to some event or condition within the control program.
Disable Network When set, the scanner is functionally removed from the network.
Reserved
Reset
n/a
Restarts access to the DeviceNet network.
n/a
Reserved
(1)
Reserved
n/a
(1)
DO NOT manipulate Reserved Bits. Doing so may interfere with future compatibility.
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Output Data Image
DeviceNet I/O Image 5-9
The Output Data Image can be up to a 180 word array. The controllers output data will be delivered across DeviceNet to the destination slave devices. The scanner’s scanlist configuration will determine how this data is actually sent to the slave device (polled, cyclic, or change of state).
Table 5.14 Output Data Image
Output Word
2 to 181
Description
DeviceNet Slave output and/or master input data
Slave mapping is done using RSNetWorx.
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5-10 DeviceNet I/O Image
Notes:
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Key features
- Connects up to 64 DeviceNet slave devices
- Provides a gateway between CompactLogix controllers and DeviceNet devices
- Uses the RSNetWorx for DeviceNet software for configuration
- Supports both explicit and implicit messaging
- Provides diagnostic information for troubleshooting
- Has a built-in watchdog timer to ensure reliable operation