140DVO85300模块备件

140DVO85300

ASI模块为每个模块维护一组调整值
输入通道。这些值可校正偏移和增益误差
在输入通道中。原始模数转换器计数
使用校准数据将值转换为实际输入信号值。
对于热电偶输入，对冷态进行调整
热电偶的结温。另外，
然后应用用户指定的调整，如果已经
用FC 217定义。终校正的输入读数为
使用热电偶或转换为工程单位
RTD转换表，或工程单位零点和量程
为输入指定的值。
以下各节描述了各种类型的输入值
调整。
输入校准
每个输入通道在工厂进行校准。在校准过程中，识别任何偏移和增益误差
并计算所需的校正系数，并将其存储在
模拟输入模块的非易失性存储器。
当输入通道被扫描到
纠正读数。校准调整应用于：
有源通道和冷结参考输入。
冷端补偿
热电偶输入通道针对冷端进行调整
温度冷接点参考可以是
I/O模块终端上的内置参考
单位或源自任何其他功能代码块的值
输出系统中的任何位置。冷接点参考
假设由控制器提供的温度为摄氏度
ASI模块将此值转换为毫伏，并将其添加到
来自模数转换器的值。
热电偶通道确定为冷接点参考
输入（FC 216，规格S4）使用内置冷接点
终端装置的冷端补偿参考。
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自动调整和校正
用户增益和偏移调整
用户指定的线性调整可应用于输入
转换为工程单位之前的信号。这个增益和
偏移量应用于所有补偿后获得的值
并且执行校正操作。
用户偏移和增益补偿用于用户校正的输入信号。例如，如果0至10 VDC模拟输入为0.1 VDC
过高时，ASI模块可以通过为该通道和输入类型添加-0.1的偏移值来补偿该偏移。
对于高电平输入，用户增益值乘以伏特，乘以
低电平输入和热电偶输入的毫伏，以及
电阻式温度检测器输入的欧姆。默认用户增益值为1。
用户偏移被添加到输入信号。偏移单位被指定为高电平输入的伏特、低电平输入的毫伏，
电阻式温度检测器输入为欧姆。默认用户偏移量为
零可以为指定单独的用户增益和偏移值
每个输入通道和每个输入类型。可以使用FC 217设置和重置用户增益和偏移值，
用户增益和偏移值保留在非易失性存储器中，以及
当模块电源中断时不会丢失。有关更多信息，请参阅编写器功能代码应用手册中的FC 217。
工程单位换算
热电偶和RTD输入转换为FC 216中规定的温度单位，即摄氏度或华氏度。转换表表示电压（或电阻）到
温度关系用于此转换。这个
用于执行转换的表取决于
指定了输入信号类型。
如果输入被识别为毫伏或高电平电压，
则指定的工程单位零和量程值为：
用于将输入读数转换为缩放工程单位
价值如果在转换为工程单位（FC 215和FC 216外部）之前需要进行特殊计算
块），然后是函数中指定的零和量程值
代码应设置为表示
输入然后，I/O模块FC 216将输出校正后的
可在控制器中处理的电压输入读数

140DVO85300

140DVO85300

The ASI module maintains a set of adjustment values for each
input channel. These values correct for offset and gain errors
in the input channel. The raw analog-to-digital converter count
value is converted to an actual input signal value using the calibration data.
For thermocouple inputs, an adjustment is made for the cold
junction temperature of the thermocouple. An additional,
user-specified adjustment is then applied, if one has been
defined with FC 217. The final corrected input reading is then
converted to engineering units using either thermocouple or
RTD conversion tables, or the engineering unit zero and span
values specified for the input.
The following sections describe the various types of input value
adjustments.
Input Calibration
Each input channel is calibrated at the factory. During the calibration procedure, any offset and gain errors are identified
and required correction factors are calculated and stored in the
analog input module's nonvolatile memory.
These factors are used when the input channel is scanned to
correct the reading. A calibration adjustment is applied to
active channels and the cold junction reference input.
Cold Junction Compensation
Thermocouple input channels are adjusted for cold junction
temperature. The cold junction reference can either be the
built-in reference available on the I/O module's termination
unit or a value originating from any other function code block
output anywhere in the system. The cold junction reference
supplied by the controller is assumed to be in degrees C. The
ASI module converts this value to millivolts and adds it to the
value from the analog-to-digital converter.
Thermocouple channels identified to be cold junction reference
inputs (FC 216, specification S4) use the built-in cold junction
reference on the termination unit for their cold junction compensation.
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Automatic Adjustments and Corrections
User Gain and Offset Adjustment
A user-specified linear adjustment can be applied to the input
signal before it is converted to engineering units. This gain and
offset is applied to the value obtained after all compensation
and correction operations are performed.
User offset and gain compensates input signals for user corrections. For example, if a 0 to 10 VDC analog input is 0.1 VDC
too high, the ASI module can compensate for this offset by adding an offset value of -0.1 for this channel and input type.
User gain value is multiplied by volts for high level inputs, by
millivolts for low level inputs and thermocouple inputs, and by
ohms for RTD inputs. The default user gain is a value of one.
User offset is added to the input signal. Units of offset are specified as volts for high level inputs, millivolts for low level inputs,
and ohms for RTD inputs. The default user offset is a value of
zero. Separate user gain and offset values can be specified for
each input channel and each input type. The user gain and offset values can be set and reset using FC 217. Once defined,
user gain and offset values remain in nonvolatile memory and
are not lost when module power is interrupted. For more information refer to FC 217 in the Composer Function Code Application Manual.
Engineering Units Conversion
Thermocouple and RTD inputs are converted to the temperature units specified in FC 216, either degrees C or F. Conversion tables representing the voltage (or resistance) to
temperature relationship are used for this conversion. The
table used in performing the conversion depends upon the
input signal type specified.
If the input is identified as either millivolt or high level voltage,
then the specified engineering unit zero and span values are
used to convert the input reading to a scaled engineering unit
value. If special calculations need to be performed prior to conversion to engineering units (external to FC 215 and FC 216
blocks), then the zero and span values specified in the function
code should be set to represent a standard voltage span for the
input. The I/O module FC 216 would then output a corrected
voltage input reading which may be processed in the controll