Analog Module Setup - LS Electric XGB PLC from AutomationDirect

The XGB PLC has many expansion module options. This gives the user the flexibility to customize the PLC for their specific application. Let’s discuss setting up an analog input module for our XGB PLC. We cover physically installing the module in a separate help topic, and the wiring will vary based on the module. Please refer to the documentation for your specific analog module to view the wiring information and diagrams. We also cover adding the module to the project, either automatically or manually, in a separate help topic. Once we have the module installed, wired, and added to the project, it is time to configure it. The first step for configuration is to determine if our module has a physical selector switch to select voltage or current. Some models do and others do not. Some switches are located on the front face of the module, and other switches are located on the side and will not be visible or adjustable when the PLC rack is assembled and powered up. Please refer to the documentation for your module to find out if it has switches and what each switch position means. Once we have set the switches, if there are any, to the correct signal type for our application, we can work on the software configuration. To do this we go to the project window on the left side and double click on “I/O Parameter.” This opens the "I/O Parameter" screen. We have already added the expansion modules attached to this PLC in a previous video. For a brief recap, we can add modules automatically by putting the CPU in stop mode, going to Online -> System Diagnostics -> I/O Information, and clicking the “I/O sync” button. We can then click the “Apply” button and the software will create any required variables for our I/O. We have an analog input module in slot 4. To configure the module, we will double click anywhere on the slot 4 row. This will open the “Special Module Parameter” pop-up window. For this module, we have 4 total channels. We can adjust the operation channel setting, the input range setting, the output type setting, the signal filtering, the averaging method, and the hold last value setting for some models. The operation channel setting enables or disables each channel. Disabling channels will increase the module refresh rate slightly, so it is always recommended to disable channels that aren’t in use. The input range setting deals with the analog signal coming in. If it is a current or voltage only module you can adjust the input range. If the module is a voltage or current combination module, like ours is, we can actually adjust both the range and the type of analog input. It is important the physical dipswitches on the module match the type of input. The output type setting deals with what the module outputs to the PLC CPU. This will vary based on the resolution of the module. Our module is a 14-bit input module, which would be a range of 0-16,383 counts. The software limits the output to a 16,000-count range, but you can shift the upper and lower limits of the range, or even have the value converted to a percentage of the range. These numbers will change if you have a different resolution on your input module. The filter constant, averaging method, and hold last value functions all vary significantly based on the analog input module used. They have to do with how the module cleans up the input signal, outputs it to the PLC CPU and what the module does in the event of invalid signal input. Please refer to the documentation and help files for your model for more details on each. Once we have configured these functions, we can select "OK." Please note this only changes the settings in the software. We will need to write the project to the PLC for the changes to be sent to the CPU. Once we have written the updated configuration, we can then view real time data for this input module. If we are online with the CPU, we can go to “Monitor > Special Module Monitoring.” This brings up a list of all special modules installed into our PLC rack. To select the analog input module in slot 4, we can either double click on it or select it and then click “Monitor.” This brings up the “Special Module Monitor” pop-up window. If we click on “Start Monitor” it will show us real time data from the module. I have hooked up a variable power supply to channel 0 to simulate a 0-10V analog device. As I vary the voltage, we can see the counts changing in the software. Below this, it will allow us to select a specific channel and then test our channel configuration. This is very useful for initial setup and testing of an analog input once connected to its field device. Please note this testing can only occur if the CPU is in stop mode. If you are in run mode, the test button will be grayed out. We also can view module information from this screen. Instead of clicking the monitor button for a specific slot, we would instead click “Module Info.” This brings up information about the module, including firmware revision, module status and more. The configuration for an analog output module is very similar. In our PLC, we have an analog output module in slot 3. If we double click on the slot 3 line, we see the settings available for configuration. We have the operation channel setting, the output range setting, the input type setting, and the channel output type setting. The operation channel for the output module allows us to enable or disable individual channels. Disabling channels will increase the module refresh rate slightly, so it is always recommended to disable channels that aren’t in use. The output range setting alters the electrical output from the module. The input type setting adjusts the range of counts the PLC can set the output channel to. It will vary depending on which output module is being used. The channel output type setting varies depending on which analog output module is used. Some analog output modules have additional settings not shown here. Please refer to the documentation and help files for your model for more details on each. Seeing real-time data and testing these output channels in stop mode uses the same “Special Module Monitor” screen we used for the analog input module. The module information screen is also available for analog output modules. Finally, to control these output channels, they must be enabled in the operation channel settings. Once enabled, the programmer can use the software created boolean global variable for the channel enable to actually turn on the output. These auto-generated variables can be found in the “global variables” tab of the “global/direct variables” screen.