描述
大、中型PLC都具有多路模拟量I/O模块和PID控制功能，有的小型PLC也具有模拟量输入输出。所以PLC可实现模拟量控制，而且具有PID控制功能的PLC可构成闭环控制，用于过程控制。这一功能已广泛用于锅炉、反应堆、水处理、酿酒以及闭环位置控制和速度控制等方面。
National Instruments PXI8422/4 RS232 Serial Interface
NATIONAL INSTRUMENTS NI SCB-100 I/O CONNECTOR BLOCK
National Instruments NI-DAQ PC Version 4.9.0 776250D-01
National Instruments NI 6070E PCI-MIO-16E-1 DAQ Card
VHDCI ‘M’ Series for National Instruments w/ Case
National Instruments NB-DIO-24, New In Box.
NATIONAL INSTRUMENTS ASSY, 8-PORT GPIB STRIP
Save $ National Instruments FP-TB-1 Fieldpoint Module
National Instruments GPIB-MAC Apple Computer Interface
National Instruments AT-MIO-16DE-10 card
NATIONAL INSTRUMENTS SCXI-1121 MODULE 4 CHANNEL AMP
NI National Instruments Camera Link PCI 1428 IMAQ Card
National Instruments: ER-8 with CB-50LP I/O Connector
