PDF1. Chemical Delivery in Semiconductor Manufacturing
Chemical delivery is the process of measuring and controlling the distribution of a given number of chemicals. This process is essential to the mixing of acids and bases in semiconductor manufacturing facilities. These systems must be able to accurately verify the amount of chemicals being delivered in order to successfully manufacture the delicate wafers and maintain a high yield.
In most semiconductor systems, both acids and bases are required for proper fabrication of the silicon chip. Because of this, the systems are composed of a number of flow sensors, each of which takes independent measurements with their own ground reference. These systems are equipped with industrial-strength sensors, such as the GF SIGNET 7002 Vortex Flow Sensors. The measurement from this flow sensor is provided by a frequency output with a peak-to-peak voltage of up to 24 VDC.
An NI 6624 device provides an ideal solution to measure and test such as system. With the ±48 V voltage input range, the NI 6624 device can easily acquire the 24 V output of the GF SIGNET flow sensor while providing up to 400 V transient overvoltage protection. Along with high-voltage protection, channel-to-channel isolation eliminates problems and incorrect readings that can result from ground loops, with each sensor operating with a unique ground reference. Manufacturing facilities tend to be very noisy environments, so the extra isolation also protects the NI 6624 device and the rest of the system from unexpected voltage spikes.
Using automatic code generation with NI-DAQmx, engineers can quickly configure a system to acquire the flow sensor outputs and easily develop an application to properly monitor the chemical delivery of the system. The following image shows an easy-to-use configuration window in NI-DAQmx that helps to configure and develop code quickly for the proper measurement.
As automotive standards and expectations continue to rise, more and more importance is being placed on the testing of all critical systems of an automobile. One of the key systems of any vehicle is the antilock braking system (ABS), which must go through extensive tests to assure the safety of the passengers. The reliability of the ABS is determined by the ability to quickly and repeatedly control the speed of a vehicle. The goal of ABS tests is to accurately acquire and analyze data about the speed of the car and the timing of the brakes.
An ABS test system includes encoders that transmit the angular information about the axes of the car in the form of a digital square wave. This signal can then be passed into a PC-based test and measurement system to determine the direction and speed of rotation. The MDFK-08 magnetic encoder by Baumer Electric Ltd. provides a noncontact sensor that operates in industrial environments with voltages up to 30 VDC.
The outstanding industrial features of NI 6624 devices are useful in a wide range of high-voltage automotive applications and tests. NI 6624 hardware triggering capabilities can be used to synchronize the encoder measurements with other events in the test process, such as application of the brakes.
Creating a program to measure a quadrature encoder is simple in NI-DAQmx. The NI-DAQmx Assistants can quickly generate code to acquire the basic encoder signals. The code provides a stable measurement and test system that can be deployed quickly on the test floor or in the vehicle.
3. Cut-to-Length Controller
Recent business models reveal the rising expense of planning production based on market forecasts and of keeping large amounts of inventory in storage. Because of this situation, many companies are favoring a demand-based business model where goods are not manufactured until ordered. This concept can be very important to industries where raw materials are expensive and there is a need to minimize waste and keep the amount of goods (finished or raw) in inventory.
Manufacturers who supply various length metal sheets to their suppliers have moved to incorporate cut-to-length controllers. To minimize waste and accurately control the motion of the cut-to-length guillotine, an encoder and measurement system is used to control the length of material fed through the system and to stop the system as needed.
A Koyo TRD-GK heavy-duty incremental encoder provides the necessary measurement for such a system. It provides a 6 to 30 VDC frequency output signal and operates at a maximum speed of 5,000 rpm. The output square wave of the encoder provides a test and measurement system with the required information to accurately measure the amount of material fed through the system as well as the speed and direction of the assembly line.
The implementation of an NI 6624 meets the necessary industrial requirements for a manufacturing system and provides the ease of use of a PC-based test and measurement system. Coupled with NI-DAQmx and the necessary control devices, the system offers the flexibility and ease of use required in basic to complex manufacturing facilities without requiring extensive training or programming knowledge.
4. Steam Billing
Accurate and reliable billing is an essential part of any energy supply company. Several boiler plants across the country are operated by energy companies that provide steam to end users. In order to accurately bill the customers, a system must be implemented to calculate the mass of steam being delivered.
Because this system requires the calculation of a gas rather than water, the steam meter operates best if it is composed of paddlewheel flow sensor. The Hayward FloSite 2000 Flow Sensor provides a 5-bladed rotor that offers high accuracy, even at low flow rates. This sensor is an ideal choice because it provides a simple square wave output with frequency proportional to the rate of flow, which can be measured with an affordable counter device, such as an NI 6624, and a computer-based measurement system.
In addition to channel-channel isolation, which is necessary when measuring several sensors independent of each other and their respective grounds, NI 6624 devices also feature the NI-TIO chip that assures reliable readings from multiple sensors. The counter devices also feature digital filters that can be used to remove any glitches that may occur because of bursts of steam or other anomalies in the system.
A typical program used by steam billing system would perform basic frequency measurement operations that would acquire the rates and then log that data to file for later billing use. All of these functions are easily and quickly configured using NI-DAQmx and LabVIEW.
5. Chemical Mixing Analysis and Control
Mixing is an essential operation for engineers and scientists in most chemical process industries. In order to convert the raw materials into a finished product, various ingredients must be properly combined at some point in a manufacturing process. A large mixing tank is used to combine the substances. In order to assure proper mixing without overmixing, the density and viscosity of the mixture must be measured and analyzed throughout the process.
The density of the final mixture can be calculated ahead of time and is related directly to the viscosity of the mixture. By measuring the torque of the mixer shaft, the viscosity of the mixture can be determined. As the mixture combines over time, the torque of the mixer shaft gradually changes. Using this simple measurement of the torque, an engineer or scientist can determine when a mixture is ready for the next stage of the manufacturing process.
A chemical mixing system can implement a basic torque transducer, such as the S.I. Instruments Stamosens 0125 DF Torque Sensor, to properly analyze the mixture of the chemicals. The rotor of the torque sensor can be directly connected to the mixer shaft to provide a frequency output of the torque. The output frequency will be on the order of a 100 kHz square wave and can potentially have a 30 VDC, peak-to-peak value. NI 6624 devices again meet all the requirements for such a system.
6. Basic Motion Control in an Assembly Line
Most manufacturing facilities today include automated assembly lines to quickly mass produce large volumes of finished goods and to decrease human errors in manual assembly or manufacturing. As the foundation of any assembly line, a motor and controller manage the motion of the products throughout the process. In a typical application, the motor feeds the raw material or starting product onto the assembly line. Because the system is designed to minimize waste and must be easily programmable, the engineers must be able to have specific but basic control over the action of the motor.
If we revisit the cut-to-length controller, we can see that the motor must not only be monitored for its speed and position, but it must also be controlled by a set of pulses to manage to the speed and direction. The Sanyo Denki 2-Phase Stepping Motors is one example of the type of motor used in specialty machinery and robotics such as this application. The controller, or indexer, of the system must be capable of generating the pulses and direction signals.
While motion controllers are generally used to control stepper motors to assure proper timing between the signals, the pulse-train generation and pulse-width modulation features of an NI 6624 offer similar signals that can be used in some systems that require programmable square waves to control the system. An NI 6624 has the capability of measuring the signals going into and out of the drive as well as to possibly control this complete system in one, easy-to-use device. The channel-to-channel isolation will again protect the various motors and sensors used with an NI 6624.
The features of NI-DAQmx software make the programming very easy. NI DAQ Assistant, shown in the figure below, provides an easy-to-use interface for developing your application and automatically generating the necessary code.
NI 6624 devices incorporate high-performance features for automotive, aerospace, and other industrial applications that need to interface with higher voltage, frequency output sensors. The NI-TIO chip and channel-to-channel isolation offers high accuracy and reduces noise interface in industrial settings. Applications can be seamlessly implemented with software, such as LabVIEW, which uses NI-DAQmx, offering a new level of ease of development for industrial applications. With all of these features, the number of applications that can incorporate and greatly benefit from NI 6624 devices are endless.
Related Links:
NI 6624 Counter/Timer Module
Using the NI Digital I/O High-Reliability Feature Set for Industrial Applications
