¥ 1132.00
¥ 1213.00
¥ 1332.00
¥ 688.00
¥ 688.00
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DCS系统接地是为了保证当进入DCS系统的信号、供电电源或DCS系统设备本身出现问题时,有效的接地系统能承受过载电流并可以迅速将过载电流导入大地。接地系统能够为DCS提供屏蔽层,消除电子噪声干扰,并为整个控制系统提供公共信号参考点(即参考零电位)。
当接地系统发生问题时(接地电阻过大,多点接地,接地线断线或接地线与高电压、大电流设备相接触等),会造成人员的触电伤害及设备的损坏,据了解,有些DCS系统经常“死机” (或不明原因的“死机”),大多是因为接地系统不良或存在问题所引起的。因此,完善、可靠、正确的接地,是DCS系统能够安全、可靠和良好运行的关键。
在一般情况下,DCS控制系统需要两种接地:保护地和工作地(逻辑地、屏蔽地等)。对于装有安全栅防爆措施的系统如化工行业所用的系统,还要求有本安地。
2.1保护地(CG,Cabinet Grounding)
DSDP150是为了防止设备外壳的静电荷积累、避免造成人身伤害而采取的保护措施。DCS系统所有的操作员机柜、现场控制站机柜、打印机、端子柜等均应接保护地。保护地应接至厂区电气专业接地网,接地电阻小于4Ω。
PFEA111-20 PFEA111-20 PFEA111-20
PFEA111-20 PFEA111-20 PFEA111-20
LORAD RT 125 X-RAY SYSTEM
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL L
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL m
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL p
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL n
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL q
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL r
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL o
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL c
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL b
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL m
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL e
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL f
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL g
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL i
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL j
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL k
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM DIGITAL l
DENTAL PORTABLE MOBILE X - RAY MACHINE SYSTEM w/DIGITAL
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL b8
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL b9
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL c1
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL c2
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL a1
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL a2
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL a3
DENTAL PORTABLE MOBILE X- RAY MACHINE SYSTEM DIGITAL a4
Image Systems - X Ray Monitor model M21P-H5101 21"