HIMA F3117工控自動化卡件
（A/D單位）默認(rèn)值為所選范圍類型的A/D下限。9.10.4.3輸入縮放：ALG608和ALG616默認(rèn)情況下，模塊將其配置范圍的整個范圍內(nèi)的電壓或電流輸入轉(zhuǎn)換為CPU的浮點(diǎn)值。例如，如果通道的量程為4至20mA，則模塊報告4.000至20.000之間的通道輸入值。通過修改四個信道縮放參數(shù)（低/高縮放值參數(shù)）中的一個或多個，可以針對特定應(yīng)用更改縮放工程單位范圍。縮放可以向PLC提供已轉(zhuǎn)換為其物理含義的輸入，或?qū)⑤斎胫缔D(zhuǎn)換為更易于應(yīng)用程序解釋的范圍。縮放始終是線性的，可以進(jìn)行逆縮放。所有報警值適用于縮放的工程單位值，而不是A/D輸入值。縮放參數(shù)僅設(shè)置兩組對應(yīng)值之間的線性關(guān)系。它們不一定是輸入的限制。示例1對于電壓輸入，6.0伏表示每秒20英尺的速度，1.0伏表示每秒0英尺。此范圍內(nèi)的關(guān)系是線性的。對于本例，輸入值應(yīng)表示速度而不是電壓。以下信道配置設(shè)置了此縮放：PACSystems*RX3i系統(tǒng)手冊第10節(jié)GFK-2314T 2019年9月模擬輸入模塊416高量程值（Eng單位）=20.000低量程值（英制單位）=0.000高量程值示例ALG608或ALG616對于本示例，1.0 Vdc至6.0 Vdc為正常電壓范圍，但模塊將嘗試為超出范圍的電壓縮放輸入。如果向通道輸入10.0 Vdc的電壓，模塊將返回36.000的縮放通道值。對于超出可接受范圍或無效的縮放輸入，應(yīng)用程序應(yīng)使用警報或采取其他預(yù)防措施。9.11示例2現(xiàn)有應(yīng)用程序使用傳統(tǒng)的模數(shù)（A/D）計(jì)數(shù)整數(shù)值。通過縮放和可選的16位整數(shù)輸入選項(xiàng)，可以將通道配置為報告整數(shù)計(jì)數(shù)值。在此示例中，應(yīng)用程序應(yīng)將+10 Vdc解釋為32000計(jì)數(shù)，將-10 Vdc解釋為-3200計(jì)數(shù)。以下信道配置將將±10 Vdc輸入信道縮放至±32000計(jì)數(shù)。信道值格式=16位整數(shù)高比例值（Eng單位）=32000.0低比例值（Eng單位）=-3200.0高比例值，（A/D單位）=10.000低比例值，A/D單位=-10.000電壓-10000+10000-32000計(jì)數(shù)32000圖287：縮放示例ALG608或ALG616 PACSystems*RX3i系統(tǒng)手冊第10節(jié)GFK-2314T 2019年9月模擬輸入模塊417信道參數(shù)（續(xù)）參數(shù)默認(rèn)描述正變化率極限（英制單位）0.0每秒工程單位變化率，將觸發(fā)正變化率警報。
(A/D Units) Default is Low A/D Limit of selected range type. 9.10.4.3 Input Scaling: ALG608 & ALG616 By default, the module converts a voltage or current input over the entire span of its configured Range into a floating-point value for the CPU. For example, if the Range of a channel is 4 to 20mA, the module reports channel input values from 4.000 to 20.000. By modifying one or more of the four channel scaling parameters (Low/High Scale Value parameters) from their defaults, the scaled Engineering Unit range can be changed for a specific application. Scaling can provide inputs to the PLC that are already converted to their physical meaning, or convert input values into a range that is easier for the application to interpret. Scaling is always linear and inverse scaling is possible. All alarm values apply to the scaled Engineering Units value, not to the A/D input value. The scaling parameters only set up the linear relationship between two sets of corresponding values. They do not have to be the limits of the input. Example 1 For a voltage input, 6.0 volts represents a speed of 20 feet per second, and 1.0 volt represents 0 feet per second. The relationship in this range is linear. For this example, the input values should represent speed rather than volts. The following channel configuration sets up this scaling: PACSystems* RX3i System Manual Section 10 GFK-2314T Sept. 2019 Analog Input Modules 416 High Scale Value (Eng Units) = 20.000 Low Scale Value (Eng Units) = 0.000 High Scale Value (A/D Units) = 6.000 Low Scale Value (A/D Units) = 1.000 Voltage (A/D Units) 1.000 6.000 0.000 Feet per Second (Engineering Units) 20.000 Figure 286: Scaling Example ALG608 or ALG616 For this example, 1.0 Vdc to 6.0 Vdc is the normal voltage range, but the module will attempt to scale the inputs for a voltage that lies outside the range. If a voltage of 10.0 Vdc were input to the channel, the module would return a scaled channel value of 36.000. The application should use alarms or take other precautions for scaled inputs that are outside the acceptable range or invalid. 9.11 Example 2 An existing application uses traditional analog to digital (A/D) count integer values. With scaling and the optional 16-bit integer input option, a channel can be configured to report integer count values. In this example, the application should interpret +10 Vdc as 32000 counts and -10 Vdc as -32000 counts. The following channel configuration will scale a ±10 Vdc input channel to ±32000 counts. Channel Value Format = 16-bit Integer High Scale Value (Eng Units) = 32000.0 Low Scale Value (Eng Units) = -32000.0 High Scale Value (A/D Units) = 10.000 Low Scale Value (A/D Units) = -10.000 Voltage -10,000 +10,000 -32,000 Counts 32,000 Figure 287: Scaling Example ALG608 or ALG616 PACSystems* RX3i System Manual Section 10 GFK-2314T Sept. 2019 Analog Input Modules 417 Channel Parameters (Continued) Parameter Default Description Positive Rate of Change Limit (Eng Units) 0.0 Rate of change in Engineering Units per Second that will trigger a Positive Rate of Change alarm.
