## 6 Case Study
### Monitor and Control Process  
By communicating with the person in charge of DRM, this paper demonstrates the arrival of three workpieces after assembly, namely, an IPS socket gate valve, Italian gate valve and SPS hydrant. The pressure test parameters are shown in Table 5.  
As shown in Figure 11, the host computer can monitor the full state of the pressure test process at any time. The left side of the interface provides the relevant functions, and the right side gives the detection network status and node attributes of the current state.  
The three workpiece numbers are 001 AEGA220514, 002 AAHA220514 and 003 FBKB220514 in sequence, and they have all been scanned into the network. On that day, all the workers on duty are ready to scan the code and enter the network, and the machines are running normally without failure and are numbered M01-M12. The operation process is as follows: scan the code for each individual workpiece, query the specific type of workpiece, and guide the next part of the pressure test. At the same time, perform \(Pr(p_{1})\) to assign tasks so that workers know the corresponding station that each workpiece needs to enter. Then, after all the projects that carry out the pressure test according to the workpiece pressing standard are completed, the test process data are returned to the control network, and the qualification of each item is calculated for storage. Further, \(Pr(p_{47})\) is executed to let the host computer make quality decisions. Finally, according to the different decision results, the product is selected to enter either the qualified or unqualified transition. During this period, the monitoring network always collects on-site data and displays them, while the control network is responsible for solving problems, and the two networks work together  
Figure 11: Monitoring interface.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Serial Number** & **1** & **2** & **3** \\ \hline Product type & IPS socket gate valve & Italian gate valve & SPS hydrant \\ Model & DN50 & DN60 & DN100 \\ Pressure grade & PN10 & PN10 & PN16 \\ one-side sealing & 30 & 60 & 60 \\ other-side sealing & 30 & 60 & 0 \\ shell strength & 30 & 60 & 180 \\ low-pressure test & 0 & 0 & 60 \\ Operating time & 45 & 45 & 45 \\ Total time & 135 & 225 & 345 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Product type.  
Essentially, the coordinated operation of the monitoring network and the control network makes the workpiece flow clear and the system run stably.  
After the pressure test, Figure 12 demonstrates the state-transition diagram of the three workpieces. Since the M01-M03 machines are the exclusive site for testing hydrant products, 003 FBKB220514 is assigned to machine M01, while the remaining 001 AEGA220514 and 002 AAHA220514 products are respectively assigned to machines M04 and M06 mainly according to the working hours of the workers. In addition, different items are tested according to the product type: 001 AEGA220514 and 002 AAHA220514 were subjected to three pressure tests on one side seal, the other side seal and shell strength in the assigned station, while 003 FBKB220514 was subjected to one side seal, shell strength and low-pressure tests. Furthermore, the state-transition sequence of the three workpieces is exhibited in Table 6.  
After the completion of the construction of the system, it passed the acceptance smoothly. DRM responded that it can improve production efficiency to some extent because each workpiece has evidence to rely on and can be traced back. Because the system can accurately record acceptance and rejection, the delivery rate of accepted units also greatly improved, and customer satisfaction is very high. Most importantly, the system facilitates the supervision of the status of the workshop by the upper management.