RAMIX PMC237C-008EMI机械备件
TDI16AIA 16通道数字输入终端卡作为数字现场设备中的信号设备和SC300E机箱的数字输入电路。
它规定：•现场接线的螺纹端子连接器•现场设备的电源输入
•现场回路的保险丝保护，带有保险丝故障的本地和远程指示
•过压和瞬态保护
本文件旨在提供对TAI16AIA功能的一般理解，足以在现场实施基本维护操作
TDI16AIA包括一个安装在模制载体中的PCB组件，该载体可以卡扣
安装在所有商用类型的DIN安装导轨上。与机箱的连接
背板通过一根多芯电缆连接，该电缆两端由DIN41612连接器端接。图2-2显示了TDI16AIA，DIN41612连接器连接并安装在轨道EN 50022上NS 35/5型操作理论图2-3是显示典型数字输入通道的电路图。
终端卡的电源通常由配电盘提供PDD24
其执行其双冗余电源的二极管拍卖。
数字输入电路的电源（通常来自PDD24）被馈送至输入FS1或FS2。其中不使用PDD24，需要双电源，这些电源连接到FS1和FS2并由D17和D18在终端卡上拍卖。
每个数字输入通道通过公共+ve总线的指示保险丝供电。导火索每个保险丝的“故障”输出连接到公共报警总线。如果任何保险丝故障，本地通过保险丝熔断LED LD1的照明提供指示。操作遥控器的信号报警在报警输出PL1处可用。
注PDD24具有保险丝熔断报警指示器，可提供多个输入。该设施可以：接线以提供整个机柜的保险丝熔断指示。如果需要，可通过TS1将-ve总线接地，以防止电源“浮动”断开机箱电缆时。瞬态抑制瞬态抑制器安装在SC300E机箱的每个数字输入通道输入端。它为可能出现在数字输入线上的瞬态能量脉冲提供放电路径雷击等之后。抑制器实际上是齐纳二极管，其击穿电压刚好高于
正常电源电压。因此，在正常运行中，抑制器不导通（分离来自漏电流）。在存在瞬态脉冲时，发生齐纳击穿。这个抑制器两端产生的电压在一定程度上随脉冲电流变化，并且称为“箝位”电压。
The TDI16AIA 16-channel digital input termination card acts as an interface between the digital
signalling devices in the field device and the digital input circuits of an SC300E chassis.
It provides:
• Screw terminal connectors for the field wiring
• Power supply inputs for the field devices
• Fuse protection for the field loops with local and remote indication of fuse failure
• Overvoltage and transient protection
This document is intended to provide a general understanding of the function of the TAI16AIA,
sufficient to enable basic maintenance operations to be effected in the field.PHYSICAL
The TDI16AIA comprises a PCB assembly mounted in a moulded carrier that can be snapped
onto all commercially available styles of DIN mounting rail. Connection to the chassis
backplane is via a multicore cable terminated at either end by a DIN41612 connector. Figure 2-
2 shows the TDI16AIA with the DIN41612 connector attached and mounted on rail EN 50022
type NS 35/5 THEORY OF OPERATION
Figure 2-3 is a circuit diagram showing a typical digital input channel.
Power supplies for the termination cards are normally provided by a Power Distribution Panel
PDD24 which performs diode auctioneering of its dual redundant power supplies.
Power for the digital input circuits (normally from the PDD24) is fed to input FS1 or FS2. Where
the PDD24 is not used and dual supplies are required, these are connected to FS1 and FS2
respectively and auctioneered on the termination card by D17 and D18.
Each digital input channel is powered via an indicating fuse from a common +ve bus. The ‘fuse
failed’ output from each fuse is connected to a common alarm bus. If any fuse fails, local
indication is provided by the illumination of Fuse blown LED LD1. A signal to operate a remote
alarm is available at Alarm output PL1.
NOTE
The PDD24 has a Fuse blown alarm indicator with provision for multiple inputs. This facility can
be wired to provide fuse blown indication for an entire cabinet.
The -ve bus may be grounded via TS1 if required, preventing the power supplies from ‘floating’
when the chassis cable is disconnected.TRANSIENT SUPPRESSION
A transient suppressor is fitted across each digital input channel input to the SC300E chassis.
It provides a discharge path for transient energy pulses that may appear on the digital input line
following lightning strikes etc.
The suppressor is effectively a zener diode with a breakdown voltage just above that of the
normal supply voltage. In normal operation, therefore, the suppressor does not conduct (apart
from leakage current). In the presence of a transient pulse, zener breakdown occurs. The
voltage developed across the suppressor varies to some extent with the pulse current and is
known as the ‘clamping’ voltage.
