DTDX991A模擬量輸出卡件
PD是具有手動(dòng)復(fù)位的純比例控制器。它是五種控制器類型之一，可用于一個(gè)循環(huán)基礎(chǔ)。
手動(dòng)復(fù)位允許設(shè)置控制器的輸出對(duì)于正常操作值（即，當(dāng)過(guò)程等于給定負(fù)載條件下的設(shè)定點(diǎn)）。
當(dāng)參數(shù)TD為非零?？刂破靼ㄗ詣?dòng)調(diào)諧功能，該功能：可以使用quick從操作員面板啟動(dòng)調(diào)諧功能。
當(dāng)輸入A為高（1）時(shí)，控制器將在正常自動(dòng)模式，當(dāng)?shù)停?）時(shí)，導(dǎo)致控制器
輸出以跟蹤反饋信號(hào)以消除顛簸切換到自動(dòng)時(shí)的輸出。這是通過(guò)以下方式實(shí)現(xiàn)的：強(qiáng)制重置組件R為將保持的值（GE+R）等于反饋值。當(dāng)控制器
切換為自動(dòng)時(shí)，重置組件的值將：以一定的速率更改回手動(dòng)重置MR值由MR TLAG設(shè)置確定。當(dāng)MRTRCK是設(shè)置為“是”，手動(dòng)重置MR也將跟蹤輸入A為低時(shí)的反饋信號(hào)。
輸入I，當(dāng)從低（0）變?yōu)楦撸?）或高至低
將導(dǎo)致控制器初始化（即消除在該掃描周期期間的任何比例增益動(dòng)作）。這可用于防止在更改時(shí)碰撞輸出通過(guò)開關(guān)塊使其達(dá)到設(shè)定點(diǎn)。進(jìn)程范圍指針參數(shù)應(yīng)指向包含范圍縮放的另一個(gè)函數(shù)塊，例如作為過(guò)程變量源的模擬輸入。這使控制器能夠規(guī)范化以下參數(shù)的調(diào)整參數(shù)：工藝范圍。如果未配置此參數(shù)，控制器將使用0.00-100.00的范圍縮放熱或冷加電時(shí)，輸出將初始化為MINSCALE，所有動(dòng)態(tài)元素將初始化為第一次掃描時(shí)的電流輸入。控制器輸出具有MINSCALE和MAXSCALE參數(shù)，允許對(duì)輸出信號(hào)進(jìn)行縮放工程范圍，而不是默認(rèn)值0-100 PRCT。當(dāng)控制器輸出為設(shè)置點(diǎn)到另一個(gè)控制器。當(dāng)自動(dòng)調(diào)諧設(shè)置為“是”時(shí)，可使用調(diào)諧按鈕訪問(wèn)自動(dòng)調(diào)諧功能。它可以啟動(dòng)當(dāng)回路處于自動(dòng)或手動(dòng)時(shí)。當(dāng)啟動(dòng)時(shí)，自動(dòng)調(diào)諧器用開-關(guān)代替PD控制器控制功能，將A/M模塊置于Auto（如果處于Man），并通過(guò)六個(gè)開-關(guān)周期循環(huán)控制回路同時(shí)學(xué)習(xí)其用于為PD控制器提供調(diào)諧建議的過(guò)程動(dòng)力學(xué)。
PD is a proportional only controller with manual reset. It is
one of five controller types that can be used on a one per
loop basis.
Manual reset allows the output of the controller to be set
for a normal operating value (i.e. the desired output when
the process equals setpoint under a given load condition).
Derivative action is provided when the parameter TD is
non-zero. The controller includes an autotune feature that
can be initiated from the operator faceplate using the quick
TUNE feature.
When input A is high (1) the controller will operate in the
normal auto mode and when low (0) causes the controller
output to track the feedback signal to eliminate bumping
the output when switching to auto. This is accomplished by
forcing the reset component R to a value that will keep
(GE+R) equal to the feedback value. When the controller
is switched to auto the value of the reset component will
change back to the manual reset MR value at a rate
determined by the MR TLAG setting. When MRTRCK is
set to YES the manual reset MR will also track the
feedback signal when input A is low.
Input I, when changed from low (0) to high (1) or high to
low, will cause the controller to initialize (i.e. eliminate
any proportional gain action during that scan cycle). This
can be used to prevent bumping the output when changes
are made to the setpoint through a switch block. The process range pointer parameter should point to another function block that contains range scaling, such as an
analog input that is the source of the process variable. This enables the controller to normalize tuning parameters for
the process range. If this parameter is not configured, the controller will use a range scaling of 0.00-100.00. During
a warm or cold power up the output will be initialized to MINSCALE and all dynamic elements will be initialized at
the current input on the first scan.
The controller output has MINSCALE and MAXSCALE parameters allowing the output signal to be scaled for
engineering ranges other than the default of 0 - 100 PRCT. This may be necessary when the controller output is the
setpoint to another controller.
The Autotune feature is accessible using the TUNE pushbutton when AUTOTUNE is set to YES. It can be initiated
while the loop is in Auto or Manual. The autotuner, when initiated, replaces the PD controller with an on-off
control function, places the A/M block in Auto (if in Man), and cycles the control loop through six on-off cycles
while learning the process dynamics which it uses to provide tuning recommendations for the PD controller.
