在40年代，过程控制是基于3～15PSI的气动标准信号。其后，由于4～20mA模拟信号的使用，使得模拟控制器得到了广泛应用，但是并不是所有的传感仪表和驱动装置都使用统一的4～20mA信号。70年代，由于在检测、模拟控制和逻辑控制领域率先使用了计算机，从而产生了集中控制。进入80年代，由于微处理器的出现，促使工业仪表进入了数字化和智能化的时代，4～20mA模拟信号传输逐步被数字化通信代替，加之分布式控制以及网络技术的迅速发展，促进了控制、调度、优化、决策等功能一体化的发展。然而由于检测、变送、执行等机构大都采用模拟信号连接，其传送方式是一对一结构，这使得接线复杂，工程费用高，维护困难，而信号传输精度底，易受干扰，仪表互换性差，这都阻碍了上层系统的功能发挥。另一方面，由于智能仪表的功能远远超过了现场模拟仪表，如对量程和零点进行远方设定，仪表工作状态实现自诊断，能进行多参数测量和对环境影响的补偿等。由此可见，智能仪表和控制系统的发展，都要求上层系统和现场仪表实现数字通信。
.控制网络的发展,其基本趋势是逐渐趋向于开放性、透明的通讯协议。上述出现的问题,根本原因在于现场总线的开放性是有条件的、不彻底的。以太网具有传输速度高、低耗、易于安装和兼容性好等方面的优势,由于它支持几乎所有流行的网络协议,所以在商业系统中被广泛采用。近些年来,随着网络技术的发展,以太网进入了控制领域,形成了新型的以太网控制网络技术。这主要是由于工业自动化系统向分布化、智能化控制方面发展,开放的、透明的通讯协议是必然的要求。现场总线由于种类繁多，互不兼容，尚不能满足这一要求。而以太网的TCP/IP协议的开放性使得在工控领域通讯这一关键环节具有无可比拟的优势
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SYNRAD FHIN30-125 USPP FHIN30125
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Synthesized Signal Generator, Hewlett Packard 8663A
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Synthesys Research BA14400B-PD
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Systron Donner 1702 Signal Generator
T & R Test Equipment model 100ADM mk4 Secondary Injection Test Set L K~
T damper, 12", Actuator-Jordan, 3 blade
T damper, 16", Actuator-Jordan, 3 blade, uninsulated
T&R 150 KVA 3 PHASE 4160D- 277/480Y PAD MOUNT TRANSFORMER
T&R ELECTRONIC 501-00003 USPP
T1901N80TS06 MFG EUPEC MODULE 1 PCS
T260-105 SENSORDATA SENSORS
T260-STD SENSORDATA SENSORS
T2H15S HEVI DUTY TRANSFORMERS
T338WOL Boltswitch Switch E-OK
T801/115 STANELY CONTROLLERS REMANUFACTURED
T801/115/S24 STANELY CONTROLLERS REMANUFACTURED
TA INSTRUMENTS 931001.901 NSPP
TA INSTRUMENTS 931001.902 NSPP
TA6307H09 TAPER BUSH REDUCER 906003 DODGE-RELIANCE
Taber Abraser Model # 174
Taber Industries 5130 Digital Single Station Abraser Test Tester Surface Rubbing
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TABLETS, I.MX53, SABRE PLATFORM, MCIMX53SMD 1899039
Tabor Electronics WS8101 100MHz Single-Channel Arbitrary Function Generator -
Tabor Electronics WS8251 Single-Channel Arbitrary / Function Generator -
Tabor Electronics WS8351 350MHz Single-Channel Arbitrary Function Generator -
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Tabor Electronics WW2074 Four-Channel Arbitrary Waveform Generator, 200MS/s
TAC 7716-C W/330385-01E EXPANSION BRD USPP 7716CWE
Tactilus Pressure Testing Mapping System SPI Sensor Products Inc tactile
TADIRAN Lithium battery TL-4955 2/3AA and original parts 2 month
TAGSYS Medio L-L100 Long Range Reader
TAKASAGO FX020-300 20V 300A 6KW DC Power Supply
Takex F88-056-EX Sensor C
Talesun TP660P-240 SILVER 69cents watt Container of 800 Panels
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TAMAGAWA 800123-2R USPP 8001232R
TAMAGAWA 800123-2S FA-SOLVER
TAMAGAWA BRX FA-SOLVER 800123-S (26V 2400HZ)
TAMAGAWA BRX FA-SOLVER 800123-S RESOLVER 26V 2400Hz 2-1/16" SHAFT 800123S
TAMAGAWA TS4884N9072E411 NSPP TS4884N9072E411
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Tampes Canron 340-606-401 300HP 1