I am currently facing an issue with my 2-wire analog IR temperature sensor connected to my 1769-IF4 PLC. I have successfully used a SCP instruction in Rslogix 500 and the input value is updating as expected. However, I am encountering a problem where the N7:44 register is not updating, preventing me from viewing the temperature on my PanelView HMI. The temperature range of the sensor is between -4°F and 572°F. Any suggestions or insights would be greatly appreciated. Thank you.
User jscampbell210 asked a question regarding a 2-wire analog IR temperature sensor connected to their 1769-IF4 module in Rslogix 500. Although the input value is updating, the N7:44 register is not updating, preventing the temperature from displaying on their PanelView. The sensor has a temperature range of -4° to 572°F. Any assistance would be greatly appreciated.Offline in the attached image, but updates when online.
Perform a cross-reference check for N7:44 to determine its usage throughout the PLC system. If no other references are found, consider disconnecting all peripherals except for your PC to troubleshoot and determine if the issue lies with another device writing to N7:44. This step can help identify potential conflicts causing malfunctions in the system.
Is the subroutine currently under scanning? This could be applicable in a different ladder aside from ladder 2.
The problem lies in the title of this thread. If you search for "instruction not working" on various forums and websites like this one and /r/PLC, you'll see the prevalence of this issue. In my extensive career spanning over four decades, I have only encountered one bug in a compiler. It's crucial to assume that the program and the SCP instruction are functioning as intended, as any other approach is inefficient. By starting with this assumption, you can focus on troubleshooting and determining if the PLC is executing the commands as programmed. This approach is the most effective way to identify and resolve any issues, even if there is a potential bug present. Trusting that the system is working correctly will lead to quicker problem-solving results.
It sounds like you're on the right track with the SCP instruction, but the issue with the N7:44 register not updating could be due to how you're handling the data conversion. Double-check that your scaling parameters in the SCP instruction match the input range of your temperature sensor. Additionally, ensure that the temperature data is correctly transferred to N7:44 after the scaling. It might also be worth verifying the communication settings between the PLC and the HMI to ensure everything is syncing properly. A small tweak there could make a big difference. Good luck!
It sounds like you're on the right track with your SCP instruction, but have you double-checked the scaling parameters and the way you're moving the data into N7:44? It's possible that the conversion isn't happening correctly, or the destination register isn't being updated due to some logic error. Also, make sure that the PanelView is correctly configured to read from N7:44 and that there's no display logic interfering. Sometimes, re-initializing the communication between the PLC and the HMI can also resolve display issues. Good luck!
It sounds like you're on the right track with the SCP instruction, but there might be a couple of things to check. First, ensure that the scaling parameters are correctly configured for your temperature sensor range. Also, verify the N7:44 register isn't being overwritten or incorrectly addressed in your program. Sometimes, HMI mapping can also cause issues, so make sure the PanelView is configured to read from N7:44 correctly. If all else fails, consider adding a monitor in RSLogix to see if the register updates there, which might help isolate the problem. Good luck!
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Answer: Answer: The issue with the N7:44 register not updating could be due to a configuration error or a problem with the scaling of the input values from the sensor.
Answer: Answer: You can start by checking the SCP instruction configuration in Rslogix 500, verifying the scaling settings, and ensuring that the input values from the analog IR temperature sensor are within the expected range of -4°F to 572°F.
Answer: Answer: You may need to review and adjust the scaling parameters, check for any wiring issues or sensor malfunctions, and ensure that the data is being transferred correctly between the PLC and the HMI for displaying the temperature data.
Answer: Answer: Proper configuration of the SCP instruction is crucial
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