Hey there! Recently, I installed the Ricelake 720i weight scale indicator and added the Ethernet IP module to enable communication between my PLC (L62) and the scale. To address an issue where the scale reading matches up to 32767 kg and then displays a negative value in the PLC (-31267 or something similar for any weight above 32767 kg), I've been using the SWPB swap byte instruction as per the manual. After some research, I considered converting the signed values to unsigned, but I'm unsure how to retrieve the weight from an unsigned integer. Any assistance on this matter would be greatly appreciated. Thank you!
I believe I needed to utilize the DINT data type rather than INT while awaiting its testing.
The MOV instruction copies the value of a signed integer from one memory location to another. It then performs an addition operation, increasing the value by 65536.
A more straightforward option is to use the MOV instruction to handle signed integers in the range of 0 to 65535. It is important to note that both of these techniques can only manage values up to 65535.
I am grateful for your assistance, sir. Your help is exactly what I was looking for. Thank you.
Hi there! This negative value problem indicates that the data from the scale is being interpreted as a signed integer, hence any value greater than 32767 (which is the maximum positive value for a 16-bit signed integer) is interpreted as a negative number due to integer overflow. You're on the right track with trying to convert the values to unsigned. To convert the signed values to unsigned in your PLC, you might want to look into the COP instruction to move the data into a double integer which, hopefully, can handle larger values. It may take some experimentation, but this may help eliminate your problem with negative readings.
It sounds like you're really diving deep into the integration! You're on the right track with the SWPB instruction to handle the byte order, but for the signed-to-unsigned conversion, you'll want to first ensure you're reading the scale's output correctly. Once you have the weight as an unsigned integer, simply treat it as a standard integer up to the maximum limit. If you're consistently hitting that 32767 threshold, you can offset your readings by adding 65536 when interpreting values above that. This way, you can retrieve correct weights over the limit without running into negative values. If your PLC supports it, you can also check for values over the threshold and implement conditional logic to handle them more gracefully. Hope that helps!
Hey! It sounds like you're dealing with a classic sign issue when working with those weight readings. Since you're seeing negative values, it indicates that the values are indeed being interpreted as signed integers. Using the SWPB instruction is a good way to start, but I'd recommend checking how the data is being formatted in the PLC. If you want to convert those signed values to unsigned, you could add 65536 (2^16) to any negative value to get the correct weight. Just make sure you also update any display or logic that relies on the weight reading to handle that conversion correctly. Hope this helps!
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Answer: 1. How can I address the issue of the Ricelake 720i weight scale indicator displaying negative values in the PLC when the weight exceeds 32767 kg? - The issue can be addressed by using the SWPB swap byte instruction as per the manual or by converting the signed values to unsigned.
Answer: - To convert signed values to unsigned, you may need to implement specific data conversion techniques as per the requirements of your system. Consider consulting the manual or seeking technical assistance for guidance.
Answer: - An Ethernet IP module was added to facilitate communication between the PLC (L62) and the Ricelake 720i weight scale indicator.
Answer: - You can refer to the manual for troubleshooting steps, reach out to technical support for assistance, or seek guidance from online forums and communities specializing in industrial automation and weighing systems.
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