IS200TVIBH2BBB模拟量输入模块

.输入模块在转换中未使用的%AI数据表中的位被模拟输入模块强制为0（零）。模拟电流数据字的位放置示例如下所示。此示例适用于Alog Current模块，目录号IC693ALG391。S D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X MSB LSB S=符号位X=t转换器位Alog值在转换器的范围内缩放。工厂校准将每位的数值（分辨率）调整为满刻度的倍数（即4微/位）。此校准使rl 12位转换器具有4000个计数（rlly 2 12=4096个计数）。然后，在alog范围内使用4000个计数对数据进行缩放。例如，模拟电流的D/A转换器数据按比例缩放，如图3-4所示。4 D/A位（十分之一）电流范围A4758 0 20 0 4000图9-5。IC693ALG391的D/A位与电流的比较可以在其各自的规范中找到关于模拟模块的放置和缩放的更多详细信息。通用Alog模块信息部分9 GFK–0898F第9章–通用Alog模件信息部分9-9阶梯效果由于数据字（16位）中的转换位（12位）不是右对齐的，因此转换位的放置会导致输入成为阶梯。模块阶梯的净效果是%AQ数据表的每一次增加都会导致。输入模块的净效果是，增加的输入不会导致%AI表中数据字的LSB（最低有效位）发生变化。步骤的大小取决于模拟信号的范围、转换的分辨率和忽略的LSB的数量。这些因素可用于计算台阶的大小。例如，alog模块以12位提供s。因此，每个位表示（20-4）/212位=3.906µA/位。然而，工厂校准调整为每位偶数微（4µA/位）。由于%AQ中的三个LSB未用于转换，因此%AQ需要增加8个计数（2 3）才能将模拟值更改4µA。软件舍入算法使步长在计数7和计数9之间旋转，而不是8。表3-3中提供的数值为您提供了计算步长所需的信息。下图显示了模拟电流与%AQ中相应数据字的一部分。4.004 5电流（分升）4648 0 12 21 28 37 44 4.000 4.008 4.012 4.016 4.020图9-6。楼梯台阶对Alog-Llues的影响虽然楼梯台阶是楼梯台阶，但它们可以用线性图来近似。下图显示了电压和电流之间的关系。这可以通过使用Logicster 90-30/20/Micro软件编程实现。数据转换公式如下所示。数据字（%AQ或%AI）应用程序数据值–应用程序偏移32000应用程序值–应用最小值=对于模拟输入，您需要根据模拟数据字计算应用程序数据的值。对于alog，您需要根据应用程序数据值和范围计算alog数据字。缩放的一个例子是实际代表00 rpm的伏特信号。对于sigl，将使用以下系数。数据字XrpmThe bits in the %AI data table which were t used in the conversion by the input module are forced to 0 (zero) by the alog input module. An example of the bit placement for an alog current data word is shown below. This example is for the Alog Current module, catalog number IC693ALG391. S D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X MSB LSB S=sign bit X=t converter bits Alog lues are scaled over the range of the converter. Factory calibration adjusts the alog lue per bit (resolution) to a multiple of full scale (that is, 4 micro/bit). This calibration leaves a rl 12-bit converter with 4000 counts (rlly 2 12 = 4096 counts). The data is then scaled with the 4000 counts over the alog range. For example, the data to the D/A converter for the alog current is scaled as shown in Figure 3-4. 4 D/A BITS (decil) CURRENT RANGE a44758 0 20 0 4000 Figure 9-5. D/A Bits vs. Current for IC693ALG391 More detailed infortion on placement and scaling for the alog modules can be found within their respective specifications. General Alog Module Infortion 9 GFK–0898F Chapter 9 – General Alog Module Infortion 9-9 Stair Step Effect of Because the converted bits (12 bits) in the data word (16 bits) are t right-justified, the placement of the converted bits causes the , or input, to be a stair step. The net effect of the stair step for an module is that t every increase in the %AQ data table will cause an increase in the . The net effect for an input module is that an increased input will t cause the LSB (Least Significant Bit) of the data word in the %AI table to change. The size of the step depends on the range of the alog sigl, the resolution of the conversion, and the number of LSBs disregarded. These factors can be used to calculate the size of the step. For example, the alog module provides s from in 12 bits. Therefore, each bit represents (20-4 )/212 bits = 3.906 µA/bit. However, factory calibration adjusts for an even number of micro per bit (4 µA/bit). Since the three LSBs in the %AQ are t used in the conversion, an 8 count (2 3 ) increase in the %AQ is needed to change the alog by 4 µA. The software rounding algorithm causes the step to rotate between a count of 7 and a count of 9 instead of 8. The lues supplied in Table 3-3 provide you with the infortion needed to calculate step sizes. The following figure shows a portion of the alog current versus the corresponding data word in %AQ. 4.004 5 CURRENT (decil) a44648 0 12 21 28 37 44 4.000 4.008 4.012 4.016 4.020 Figure 9-6. Stair Step Effect on Alog lues Although the alog sigls are stair step, they can be approxited with a linear graph. The following figures show the relationship between voltage and current This y be accomplished through programming with Logicster 90-30/20/Micro software. The formula for the data conversion is shown below. Data Word (%AQ or %AI) Application Data lue – Application Offset 32000 Application lue – Application Minimum lue = For alog inputs, the application data lue is what you will need to calculate for based on the alog data word. For alog s, the alog data word is what you will need to calculate for based on the application data lue and range. An example of scaling is a volt sigl that actually represents 00 rpm. For an sigl, the following factor would be used. Data Word Xrpm