Key Specifications Of Analog Input Card

Transcript

PC-base DAC’s 2005 Globe LEAP AE training Agenda ƒ ƒ ƒ ƒ ƒ Data Acquisition & Control System DA&C cards Programming introduction DLL Examples introduction and operation LabVIEW deiver installation and operation Program development in Labview (VB.NET) via ActiveDAQ Real World Application - Temperature Control Sensor Detect Signal conditioning Isothermal Block Isolation Amplifier Real World Thermocouple RTD & Thermister Temperature Sensor IC Relay Actuator A/O D/O A/I & D/I A/D & MUX Calculating System program Control What is your Scheme? (AI) System • Analog value (ex. 1.234) • Graphic Trend DA&C Card Signal • Voltage Signal Analog Input or Multi-Function card PCI ISA • Signal from sensor or transducer • Thermocouple 資料擷取系統簡介 Sensor Signal Wiring Transducer Conditioning Mux + ADC PCI BUS Wire Terminal Board DA&C+Program PC Ground Sensor: Thermocouple *ADAM 3011 Sensor for Thermocouple* ƒ Relative temperature measurement ƒ Cold junction compensation – AB work point – AC and BC free point A C B C + - Sensor: Thermocouple ƒ Made of materials A and B ƒ the contact point produces a small open-circuit voltage as a function of temperature ƒ Non-linear J type thermocouple 70 60 mV + 40 - 20 -8 -210 degree C 1200 Signal conditioning: Ground Loop Noise and Isolation Signal Source Measurement Device Signal Source Measurement Device Use isolation to break ground loop noise • High speed: ADAM-3000 • Normal speed: PCLD-779 Signal conditioning: Filter Lowpass Filter Time domian Frequency domain ƒ ƒ Time domian Frequency domain Block the noise Block all signals above a certain frequency Signal conditioning: Amplifier Amplifier Amplifying signals to match the input range of the digitizer 10 mV signal 12-bit 12-bit A/D A/D resolution: 4 step (2-bits) 10 V signal resolution: 4096 step (12-bits) A/D , D/A Converter Data Acquisition / Monitoring / Control System Physical Scale Raw Data Real Word: Wave, Normalize A/D Flow, Scaling Sensor, Temperature, Analog To Digital Converter Power 3-Bit ADC 4-Bit ADC Information CPU Memory Physical Scale ( Controllable ) Scaling/ Mapping D/A 01010101 Digital To Analog Converter 3-Bit ADC Real Word: Valve Control, Flow Control, Relay, Fan( Cooler ), Heater 4-Bit ADC 0111 0110 0101 0100 0011 0010 0001 0000 0011 0000 0001 0101 0111 0011 Sample = N/T ADC Data ADC Data Sample = 2N/T Accuracy / Resolution (I) Digitizer Resolution (±10V Range) Resolutio n Distinct Values 1 LSB (approxim ate) 8 bits 256 80mV 10 bits 1024 20mV 12 bits 4096 5mV 14 bits 16384 1.25mV 16 bits 65536 300uV The absolute accuracy expresses how precisely the digital values produced represent the analog inputs. Accuracy / Resolution (II) ƒ The number of bits that the ADC uses to represent the analog signal number of levels = 2resolution = 212 = 4,096 levels ƒ For example: PCI-1710 Gain=8; Bi:0~1.25 V – – 12-bit == 4096 divisions 1.25/4096=305uV 16-bit == 65536 divisions 1.25/65536=19uV Multiplixer Amplifier Increase the channel + _ A/D Key Specifications of Analog Input Card ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ No. of Channels Single-Ended or Differential Input Unipolar/Bipolar – Unipolar: 0~10V, Bipolar: +-5V Input Range: Gain, Resolution Sampling Rate (Share or Independent) Trigger Clock: Software, External, Pacer External Trigger start (PCI-1712,PCI-1714) Data Transfer: Polling, Interrupt, DMA FIFO Data Transfer Method ƒ Program Transfer (Software Polling) – – ƒ Interrupt Transfer – – – ƒ Foreground operation Lots of CPU time wasted during data conversion Background operation CPU is interrupted once data conversion is completed UP to 1K sample/sec DMA Transfer (PCI Bus: Bus-Mastering) – – – Background operation Data is transfer to memory directly without overhead of CPU UP to 1M sample/sec A/D Trigger Modes ƒ Software Trigger – ƒ Internal Pacer Trigger – ƒ Acquire the data through software Continuous high-speed data acquisition External Trigger – Synchronous sampling with external device Single-ended input configuration Differential input configuration I Differential input configuration II Interfacing to PCLD-8710 Digital I/O Counter From To Next Relay DA&C Terminal Board Crad CJC Calib Analog I/O Programming introduction LabView Program : Analog Input ActiveDAQ +Labview (AI) In control panel , Select Active X Method > Opendevice Function Follow Program Procedure building more different functions on Diagram ActiveDAQ +Labview (AI) What is your Scheme? (AO) System DA&C Card Signal • Analog value (ex. 1.234) • Voltage Signal • Slider or Knob • To do flow rate controlling • Current Signal Analog Output or Multi-Function card PCI ISA • To generate a wave • To drive a servo motor Key Specifications of Analog Output Card ƒ ƒ ƒ ƒ ƒ ƒ No. of Channel Unipolar: 0~10V, Bipolar: +-5V Resolution Sampling Rate Data Transfer: Polling,DMA FIFO LabView Program : Analog Input LabView Program : Analog Input & Output ActiveDAQ +Labview (AO) What is your Scheme? (DI) System DA&C Card • Boolean Logic On /Off • Voltage Signal • Indicator • Push button Digital Input Card PCI ISA • Dry contact Key Specifications of Digital Input Card ƒ ƒ ƒ ƒ ƒ ƒ No. of Channel TTL / Isolation DI Input range Interrupt Function Data Transfer: Polling,DMA(PCI-1755) Latch Non-Isolated D I/O Wire configuration Isolated D I/O Wire configuration (1) LabView Program : Digital Input What is your Scheme? (DO) System DA&C Card • Boolean Logic • Switch or Button On /Off • On/Off control Digital Output Card • To toggle a valve • To active a alarm PCI ISA Key Specifications of Digital Output Card ƒ ƒ ƒ ƒ ƒ ƒ No. of Channel Output range TTL / Isolation DO / Relay (Form A,B,C) Keeps Status when hot system reset Watchdog Timer (PCI-1758UDO/UDIO) Data Transfer: Polling,DMA(PCI-1755) Isolated D I/O Wire configuration (2) LabView Program : Digital Output ActiveDAQ +Labview (DI+DO) ActiveDAQ +Labview (DI+DO) What is your Scheme? (Counter) System DA&C Card Square Wave • Indicator • Voltage Signal • Numeric Display • Sequential pulse signal Counter Card PCI ISA LabView Program : Counter input LabView Program :Frequency measure ActiveDAQ +Labview (Pulse output) Thanks you!