RAMIX PMC237C-008EMI機械備件
TDI16AIA 16通道數(shù)字輸入終端卡作為數(shù)字現(xiàn)場設(shè)備中的信號設(shè)備和SC300E機箱的數(shù)字輸入電路。
它規(guī)定：?現(xiàn)場接線的螺紋端子連接器?現(xiàn)場設(shè)備的電源輸入
?現(xiàn)場回路的保險絲保護(hù)，帶有保險絲故障的本地和遠(yuǎn)程指示
?過壓和瞬態(tài)保護(hù)
本文件旨在提供對TAI16AIA功能的一般理解，足以在現(xiàn)場實施基本維護(hù)操作
TDI16AIA包括一個安裝在模制載體中的PCB組件，該載體可以卡扣
安裝在所有商用類型的DIN安裝導(dǎo)軌上。與機箱的連接
背板通過一根多芯電纜連接，該電纜兩端由DIN41612連接器端接。圖2-2顯示了TDI16AIA，DIN41612連接器連接并安裝在軌道EN 50022上NS 35/5型操作理論圖2-3是顯示典型數(shù)字輸入通道的電路圖。
終端卡的電源通常由配電盤提供PDD24
其執(zhí)行其雙冗余電源的二極管拍賣。
數(shù)字輸入電路的電源（通常來自PDD24）被饋送至輸入FS1或FS2。其中不使用PDD24，需要雙電源，這些電源連接到FS1和FS2并由D17和D18在終端卡上拍賣。
每個數(shù)字輸入通道通過公共+ve總線的指示保險絲供電。導(dǎo)火索每個保險絲的“故障”輸出連接到公共報警總線。如果任何保險絲故障，本地通過保險絲熔斷LED LD1的照明提供指示。操作遙控器的信號報警在報警輸出PL1處可用。
注PDD24具有保險絲熔斷報警指示器，可提供多個輸入。該設(shè)施可以：接線以提供整個機柜的保險絲熔斷指示。如果需要，可通過TS1將-ve總線接地，以防止電源“浮動”斷開機箱電纜時。瞬態(tài)抑制瞬態(tài)抑制器安裝在SC300E機箱的每個數(shù)字輸入通道輸入端。它為可能出現(xiàn)在數(shù)字輸入線上的瞬態(tài)能量脈沖提供放電路徑雷擊等之后。抑制器實際上是齊納二極管，其擊穿電壓剛好高于
正常電源電壓。因此，在正常運行中，抑制器不導(dǎo)通（分離來自漏電流）。在存在瞬態(tài)脈沖時，發(fā)生齊納擊穿。這個抑制器兩端產(chǎn)生的電壓在一定程度上隨脈沖電流變化，并且稱為“箝位”電壓。
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.
