Manual

5-2 VSM500 DeviceNet Option Board
5.2 Example of I/O Messaging
For example, Output Assembly 21 uses the following data format:
:
Input Assembly 71 uses the following data format:
Figure 5.1 illustrates how data in Output Assembly 21 and Input Assembly 71 will be
transmitted between a VSM500 unit and an SLC processor. Notice that the terms
input and output are defined from the scanner’s point of view. Also notice that explicit
messaging can be transmitted as well.
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0NetRef Net
Control
Fault
Reset
RunRev RunFwd
1Not Used
2 Speed Reference RPM (Low Byte)
3 Speed Reference RPM (High Byte)
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0At
Reference
RefFrom
Net
CtrlFrom
Net
Ready Running
Reverse
Running
Forward
Faulted
1Not Used
2 Speed Actual RPM (Low Byte)
3 Speed Actual RPM (High Byte)
Figure 5.1 – Example I/O Image
SLC Scanner VSM500 Unit and DeviceNet Option
DeviceNet
Output
Image
(Write)
Input
Image
(Read)
Explicit
Message
Handler
Explicit
Message
Buffer
0 - Network Status
1 - Not Used
2 - Actual Speed (Low Byte)
3 - Actual Speed (High Byte)
0 - Network Control
1 - Not Used
2 - Speed Reference (Low Byte)
3 - Speed Reference (High Byte)
Byte