140XBP00600模块备件

140XBP00600

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本节解释了输入、控制逻辑、通信和通信，
以及IMASI23模块的连接。ASI模块
将16个模拟输入连接到和声控制器。和谐控制器通过
I/O扩展器总线（图1-1）。总线上的每个I/O模块都有一个
由其地址双列直插开关（S1）设置的地址。
模块描述
ASI模块由单个印刷电路板组成，该印刷电路板：
占用模块安装单元（MMU）中的一个插槽。模块前面板上的两个固定闩锁将其固定到模块上
安装单元。
ASI模块有三个外部卡边缘连接器
信号和电源：P1、P2和P3。P1连接到电源
电压。P2将模块连接到I/O扩展器总线，
它通过该总线与控制器通信。连接器P3
将终端电缆的输入端插入
终端单元（TU）。现场接线的接线端子为：
在终端单元上。
模块上的单个双列直插开关设置其地址或选择
船上测试。跳线配置模拟输入信号的类型。
功能操作
ASI模块是一个带板载的智能模块
微控制器和存储器。它通过以下接口连接到控制器：
I/O扩展器总线。板载微控制器允许
ASI模块执行输入通道处理。这
允许控制器执行其他任务。输入处理任务
包括误差补偿、调整和转换为
工程单位。
2-2 WBPEEUI240774A0
功能操作
每个通道提供欠量程、超量程和开路输入
侦查板载电路检测到开路磁场导线或
断开终端单元电缆。打开输入检测是
为毫伏、热电偶、电阻式温度检测器、1至5伏直流电和4至
20毫安输入类型，可检测以下任意组合：
打开输入线。
图2-1显示了IMASI23模块的框图。
隔离A/D转换器
每个输入通道都有一个A/D转换器（delta-sigma型）。
隔离由DC/DC转换器完成（每个通道一个），以及
A/D转换器数字串行线上的光耦合器。
每个通道接受电压和电阻输入。通过数字化电压降进行电阻测量
在输入电阻源两端产生。精密恒流源提供用于测量
输入
冷接点参考
ASI模块测量模拟输入模块终端单元上的冷结RTD。这导致
现场导线处环境温度的准确读数
终端区域。此值可由ASI模块用于：
补偿双金属产生的电压
图2-1.IMASI23功能框图
D IG ital
多路复用器
NVRAM
双端口
内存
记忆
不，不，不
内存
DPRAM
微控制器
发光二极管
在D IC ATO R S中
8-PO位置
双列直插开关S1
P3连接器
关于IMASI23
来自
T E R M在IO N
装置
输入/输出
E X PA N D E R
公共汽车
接口
P2
连接器
关于IMASI23
往返
控制器
E X PA N D E R
公共汽车
正式舞会
SRAM
冷接点
参考输入
A/D转换器
O L在E D A/D
转换器1
O L在E D A/D
转换器2
O L在E D A/D
转换器3
•
•
•
•
O L在E D A/D
转换器16
T01062C
功能操作
WBPEEUI240774A0 2-3
通过端接现场导线（热电偶）进行的连接
导线）连接到终端单元的接线板上。
ASI模块上热电偶输入使用的冷结参考的块地址包含在FC 215中，
规范S3。
每个模拟输入模块配置为热电偶输入
需要冷接点参考。每个模拟输入模块
只能有一个引用，多可由16个引用使用
热电偶输入。例外情况是当
输入用作远程冷接点参考。
有关更多信息，请参阅第4节。
数字输入多路复用器（MUX）
一旦隔离、数字化和缓冲，输入信号即被发送
通过数字多路复用器连接到微控制器。所有输入，
如图2-1所示，包括参考和冷结输入在内的多个输入被多路复用。
微控制器和存储器
机载微控制器

140XBP00600

140XBP00600

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This section explains the inputs, control logic, communication,
and connections for the IMASI23 module. The ASI module
interfaces 16 analog inputs to a Harmony controller. The Harmony controller communicates with its I/O modules over the
I/O expander bus (Fig. 1-1). Each I/O module on the bus has a
unique address set by its address dipswitch (S1).
Module Description
The ASI module consists of a single printed circuit board that
occupies one slot in a module mounting unit (MMU). Two captive latches on the module front panel secure it to the module
mounting unit.
The ASI module has three card edge connectors for external
signals and power: P1, P2 and P3. P1 connects to the supply
voltages. P2 connects the module to the I/O expander bus,
over which it communicates with the controller. Connector P3
carries the inputs from the termination cable plugged into the
termination unit (TU). The terminal blocks for field wiring are
on the termination unit.
A single dipswitch on the module sets its address or selects
onboard tests. Jumpers configure the type of analog input signals.
Functional Operation
The ASI module is an intelligent module with an onboard
microcontroller and memory. It interfaces to a controller over
the I/O expander bus. An onboard microcontroller allows the
ASI module to perform the input channel processing. This
allows the controller to do other tasks. Input processing tasks
include error compensation, adjustments, and conversion to
engineering units.
2 - 2 WBPEEUI240774A0
Functional Operation
Each channel provides underrange, overrange, and open input
detection. Onboard circuitry detects either open field wires or a
disconnected termination unit cable. Open input detection is
provided for millivolt, thermocouple, RTD, 1 to 5 VDC, and 4 to
20 milliampere input types and can detect any combination of
open input wires.
Figure 2-1 shows a block diagram of the IMASI23 module.
Isolated A/D Converter
Each input channel has an A/D converter (delta-sigma type).
Isolation is done by DC/DC converters (one per channel) and
optocouplers on the digital serial line of the A/D converter.
Each channel accepts voltage and resistance inputs. Resistance measurements are made by digitizing the voltage drop
created across the input resistance source. A precision constant current source supplies the current used to measure the
input.
Cold Junction Reference
The ASI module measures the cold junction RTDs on the termination unit of the analog input module. This results in an
accurate reading of the ambient temperature at the field wire
termination area. This value can be used by the ASI module to
compensate for voltages generated from the bimetal
Figure 2-1. IMASI23 Functional Block Diagram
D IG ITA L
MULTIPLEXER
NVRAM
DUAL PORT
RAM
MEMORY
N O N VO LATILE
RAM
DPRAM
MICROCONTROLLER
LED
IN D IC ATO R S
8-PO SITIO N
DIPSWITCH S1
P3 CONNECTOR
ON IMASI23
INPUTS FROM
T E R M IN AT IO N
DEVICE
I/O
E X PA N D E R
BUS
INTERFACE
P 2
CONNECTOR
ON IMASI23
TO/FROM
CONTROLLER
E X PA N D E R
BUS
PROM
SRAM
COLD JUNCTION
REFERENCE INPUT
AND A/D CONVERTER
IS O L AT E D A /D
CONVERTER 1
IS O L AT E D A /D
CONVERTER 2
IS O L AT E D A /D
CONVERTER 3
•
•
•
•
IS O L AT E D A /D
CONVERTER 16
T01062C
Functional Operation
WBPEEUI240774A0 2 - 3
connections made by terminating the field wires (thermocouple
wires) onto the terminal blocks of the termination unit.
The block address of the cold junction reference used by thermocouple inputs on the ASI module is contained in FC 215,
specification S3.
Each analog input module configured for a thermocouple input
requires a cold junction reference. Each analog input module
can only have one reference which can be used by up to 16
thermocouple inputs. The exception to this is when one of the
inputs is used as a remote cold junction reference.
Refer to Section 4 for more information.
Digital Input Multiplexer (MUX)
Once isolated, digitized, and buffered, the input signal is sent
to the microcontroller by a digital multiplexer. All the inputs,
including the references and cold junction input, are multiplexed as shown in Figure 2-1.
Microcontroller and Memory
The onboard microcontrol