The ongoing Covid-19 situation has changed the way Missouri S&T professors deliver courses, including laboratory courses. The move to online coursework in spring 2020 required tremendous dedication and resolve for most faculty, staff and students, but one lab had been prepared for this moment for years.
Kelvin Erickson’s automation engineering lab has supported online and distance education since 2011 thanks to a cooperative agreement with Missouri State University in Springfield that allows MSU engineering students to take online classes from S&T faculty. The basic philosophy is to allow online students to remotely operate the scaled processes located in the lab at S&T.
Six stations are currently configured for online education, as illustrated in Figure 1. Figure 2 shows two of the actual lab stations. Each station is centered on a dedicated meeting PC and ceiling-mount PTZ (pan/tilt/zoom) camera. The meeting PC hosts videoconferencing software for the online “meeting room” that provides a two-way video and audio link. The meeting PC connects to a large-screen wall-mounted monitor that also provides sound, a USB microphone and a ceiling-mount camera. The video output from the camera connects to an external video-capture module linked by USB to the meeting PC. Online students use a PC, webcam and microphone.
The video image from the lab’s ceiling-mount camera is the default image for the meeting. If the online students need to control the ceiling-mount camera, they can do so by logging into its IP address and accessing the camera controls from the browser. Online students can share their screen on the lab’s large screen monitor so that the teaching assistant can see, much like looking over the shoulder of students present in the lab.
Online students access the PLC programming software via remote desktop into one of the S&T lab PCs or using a pool of virtual machines (VMs). The VM pool lets online students access the PLC programming software during class when the PCs are in use.
The lab can operate with students at a satellite campus, students online in different locations or a split between online and in-lab students.
Providing access to the touch screen panel that lets students interact PLC processor as part of the lab exercise can be challenging. Figure 3 shows the touch panel for the Heat/Vent Lab, where the students develop a program to control the pressure and temperature of a heating duct, including configuring and tuning PID controllers. The four possible options for access are shown in Figure 4:
1. Internet-accessible panel – The touch panel is remotely accessed with a browser. Depending on the manufacturer, client software may need to be downloaded to provide the remote access function. The touch panel is programmed to communicate with the PLC processor over Ethernet. The touch panel must have the driver to communicate with the PLC. If not possible, then one of the next two options is used.
2. Internet-accessible panel to intermediate PLC – Like option 1, except the touch panel communicates with an intermediate PLC that uses normal discrete inputs/outputs to connect to the processor utilized for the lab exercise. This option works with any processor, as the touch panel does not communicate with the processor.
3. Touch-screen PLC – Like option 2, except the intermediate PLC has a built-in touch panel.
4. Traditional HMI – There is no touch panel required, as the screen is developed on the lab PC and interacts with the PLC processor in the usual way.
The above description of the options assumes that one or more of the lab team members are online. Team members in the lab use the touch screen in the lab. Combinations of the above are also possible. For example, the lab exercise that features programming a fairly complex HMI screen on the PC for an automated storage/retrieval system also has a small touch screen for rudimentary control in case these functions are needed before finishing the complete screen.
Figure 1. Laboratory station system for online/remote operation.
Figure 2. Stations in S&T laboratory.
Figure 3. Touch screen for heat/vent laboratory exercise.
Figure 4. Online operator interface options: (a) internet-accessible panel; (b) internet-accessible panel to intermediate PLC; (c) intermediate PLC with touch-screen PLC; (d) traditional HMI.