Page 245 - Mechanical Engineers' Handbook (Volume 2)

234 Data Acquisition and Display Systems

Multiple server/clients with OPC

Operator
monitoring
Statistics
Unit entry to history
OPC provides
clearing house
for process data:
Defect
detection • Real-time
• Event Driven
• Standard
Unit
totalization

Diagnostic Defect
logging alerts

Figure 8 Example use of OPC communications.

can monitor the same OPC sources to perform work. Diagnostics can monitor the same data
to evaluate system processing, downtime, or quality issues. Other programs can sample and
store data to log files or diagnostic files for further analysis. All can be operating in parallel
with no need to understand the internals of the other programs, via a standard interface and
standard protocols that support asynchronous delivery of data.

8.6 Benefits of Standard Communications
When implementing data acquisition and display systems, the ability to communicate in a
standard fashion can play a large role in the cost of the system. This is realized in a variety
of ways:
1. Different sensors can be connected to a system without having to buy a whole new
system.
2. Data can be sent to other systems as needed for further processing.
3. As technology or need changes, portions of a system can be mixed and matched.
4. Increased competition from vendors tends to bring prices down.
5. A standard will have many people using products based on the standard, resulting
in more vendors and greater availability of parts with a greater variety of options.

9 OTHER DATA ACQUISITION AND DISPLAY TOPICS
9.1 Data Chain
As materials and parts move through a manufacturing operation, the data collected are sep-
arated by time and type of data. Combining that data together presents a number of chal-