3BDH000014R1输入特性模件,3BDH000014R1参数说明
数模转换器
D/A转换器接收来自微处理器。它将数据从数字字转换为等效模拟信号。D/A转换器将模拟日志位置需求输出到位置误差电路。位置误差位置误差电路将位置需求与位置反馈进行比较。该电路的输出为差值在位置反馈和位置需求信号之间。
该信号传输至伺服放大器。当位置需求和位置反馈为相同的当放大器输出为零时，表明执行器处于正确位置，伺服放大器保持伺服阀就位，执行器保持其位置。
3BDH000014R1输入特性模件伺服放大器伺服放大器提供驱动伺服阀的电源。
有两个伺服驱动输出并联，在控制输出中提供冗余。每个输出连接到单独的线圈。伺服阀操作只需要一个工作线圈。一个输出可以对地短路或开路，而不影响其他伺服驱动输出。如果一个伺服驱动输出失败，则其他输出能够驱动伺服阀。
抖动振荡器抖动振荡器将小幅度的振荡引入伺服阀，以帮助其克服摩擦的影响。
在阀门位置很少变化的系统中，抖动振荡器防止阀门冻结在一个位置。
位置反馈块由三部分组成（参见图2-4）：
•解调器。
•A/D转换器。
•LVDT振荡器。
解调器LVDT二次侧通过产生与变压器铁心位置成比例的差分电压来响应液压执行器的移动，该变压器铁心随着电压的变化而移动执行器移动。由于LVDT次级是线性的，因此校准变压器二次侧的感应电压具有全范围的节流阀。有一个最大值
DIGITAL-TO-ANALOG CONVERTER
The D/A converter receives the position demand from the
microprocessor. It converts the data from a digital word to an
equivalent analog signal. The D/A converter outputs the ana
log position demand to the position error circuit.
POSITION ERROR
The position error circuit compares position demand with posi
tion feedback. The output of this circuit is the difference
between the position feedback and the position demand signal.
This signal goes to the servo amplifier. The position error out
put is zero when position demand and position feedback are
equal. When the amplifier output is zero, indicating that the
actuator is in the correct position, the servo amplifier holds the
servo valve in place and the actuator holds its position.
SERVO AMPLIFIER
The servo amplifier provides the power to drive the servo valve.
There are two servo drive outputs in parallel providing redun
dancy in the control output. Each output connects to separate
coils. Servo valve operation requires only one functioning coil.
One output can short to ground or open without affecting the
other servo drive output. If one servo drive output fails, the
other output is able to drive the servo valve.
DITHER OSCILLATOR
The dither oscillator introduces an oscillation of small magni
tude to the servo valve to help it overcome the effect of friction.
In systems where valve position rarely changes, the dither
oscillator prevents the valve from freezing in one position.
Position Feedback
There are three parts to the position feedback block (see
Figure :
•
Demodulator.
•
A/D converter.
•
LVDT oscillator.
DEMODULATOR
The LVDT secondaries respond to the movement of the hydrau
lic actuator by generating a differential voltage that is propor
tional to the position of a transformer core that moves as the
actuator moves. Since the LVDT secondary is linear, the
induced voltage on the transformer secondary is calibrated
with the full range of the throttle valve. There is a maximum
