I am currently engaged in a project involving the integration of CompactLogix L33 and BK9055 (Beckhoff RIO) for a client utilizing NTC 1.8k temperature sensors. To interface with these sensors, we have acquired a KL3208 card. However, due to the non-linear nature of the NTC sensors, I am faced with the challenge of scaling the NTC 1.8k readings in Studio 5000 for accurate temperature values. Beckhoff has advised me that direct scaling of the NTC card signal to the CompactLogix is not possible, and a scaling formula needs to be implemented in the PLC. I am seeking guidance on how to execute this scaling process in Studio 5000. Is there an existing AOI (Add-On Instruction) available for this specific task? Additionally, I have come across information about coefficients A, B, and C for NTC 1.8k sensors. Do all NTC 1.8k sensors share the same coefficients, or does each sensor have its unique set of coefficients? Your assistance on this matter would be greatly appreciated.
The scaling blocks I have encountered typically follow a linear pattern from minimum to maximum raw values to minimum to maximum EU. In cases where a non-linear scale is needed, it is recommended to create a custom scale using CPT instructions. The Beckhoff module offers support for 1.8k sensors as a configuration option, although it is important to note that not all 1.8k sensors have the same curve. It is advisable to refer to the manufacturer's table or curve which outlines the resistance to temperature for the specific 1.8k sensor being used.
In terms of executing the scaling process in Studio 5000, you won’t typically find a ready-made AOI for a specific NTC sensor. However, you can create your own by implementing the Steinhart-Hart equation (which is widely used for thermistor linearization) in the ladder logic. As for the coefficients A, B, and C you mentioned for NTC 1.8k sensors, their values can vary based on each sensor's characteristics despite sharing the same resistance at 25°C. The manufacturer usually provides these parameters. I suggest you double check your sensor's datasheet or consult with your sensor's manufacturer to confirm this information. It's critical to use the correct coefficients to ensure accurate temperature readings.
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Answer: - Answer: Direct scaling of the NTC card signal to the CompactLogix is not possible, and a scaling formula needs to be implemented in the PLC. Specific guidance on executing this process in Studio 5000 may be required.
Answer: - Answer: It would be helpful to explore if there is an AOI specifically designed for this task to simplify the scaling process.
Answer: - Answer: NTC 1.8k sensors may have specific coefficients A, B, and C that need to be considered for accurate temperature readings. It is important to determine if each sensor has its unique set of coefficients or if there are common coefficients shared among these sensors.
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