HIEE320693R0001处理器卡件,HIEE320693R0001使用过程
用于90-30系列可编程逻辑的4通道模拟电压输入模块控制器提供四个输入通道，每个通道能够将模拟输入信号转换为根据应用要求使用的数字信号。模拟电压输入模块为能够转换-10至+10伏范围内的输入。每个四个通道是一毫秒。这为任何频道转换信号的分辨率为12位二进制（4096中的1部分）。%AI寄存器中的用户数据是16位2的补码格式。
HIEE320693R0001处理器卡件12的位置%AI数据字中来自A/D转换器的位如下所示。之间的关系A/D转换器的电压输入和数据如图3-10所示。模块中还提供了有限电流输入模式。在用户身上提供跳线每个通道的端子连接器，可用于连接内部250欧姆分流器电阻进入电路。分流电阻器有效地提供–40至+40 mA的电流输入范围然而，输入电流通常不应超过±20 mA，以避免自热和相应的精度损失。4至20 mA输入对应于电压输入模块的1至5伏输入；因此，4到20 mA输入的分辨率信号约为10位二进制（1024中的1部分）。分辨率可以提高到使用精度为250欧姆的电阻器代替跳跃者电阻器使电压输入模块将4至20 mA输入视为2至10伏。
The 4-Channel Analog Voltage Input module for the Series 90-30 Programmable Logic
Controller provides four input channels, each capable of converting an analog input signal to a
digital signal for use as required by your application. The Analog Voltage Input module is
capable of converting inputs in the range of –10 to +10 volts. Conversion speed for each of the
four channels is one millisecond. This provides an update rate of four milliseconds for any
channel. Resolution of the converted signal is 12 bits binary (1 part in 4096).
User data in the %AI registers is in 16-bit 2’s complement format. The placement of the 12
bits from the A/D converter in the %AI data word is shown below. The relationship between
the voltage input and the data from the A/D converter is shown in Figure 3-10.A limited current input mode is also provided in the module. A jumper is provided on the user
terminal connector for each channel, which may be used to connect the internal 250 ohm shunt
resistor into the circuit. The shunt resistor effectively provides a –40 to +40 mA current input
range. However, the input current should generally not exceed ±20 mA, to avoid self-heating
of the input resistor and a corresponding loss of accuracy. A 4 to 20 mA input corresponds to a
1 to 5 volt input to the voltage input module; therefore, the resolution of the 4 to 20 mA input
signal is approximately 10 bits binary (1 part in 1024). The resolution can be increased to
approximately 11 bits (1 part in 2048) by using a precision 250 ohm resistor in place of the
jumper. The resistor causes the voltage input module to see a 4 to 20 mA input as 2 to 10 volts.
