公开(公告)号：EP0571122B1

公开(公告)日：1998-08-12

申请号：EP93303625.3

申请日：1993-05-11

申请人： TEXAS INSTRUMENTS INCORPORATED

发明人： Miller, Mark E. ,  Sawyers, Alan R. ,  Nold, Craig M. ,  Eifler, Mark A. ,  Rowlette, Mitchell R.

IPC分类号： H01H9/56 ,  H01H47/32

CPC分类号： H01H9/56 ,  H01H2009/566 ,  Y10T307/951

公开(公告)号：EP0571122A1

公开(公告)日：1993-11-24

申请号：EP93303625.3

申请日：1993-05-11

申请人： TEXAS INSTRUMENTS INCORPORATED

发明人： Miller, Mark E. ,  Sawyers, Alan R. ,  Nold, Craig M. ,  Eifler, Mark A. ,  Rowlette, Mitchell R.

IPC分类号： H01H9/56 ,  H01H47/32

CPC分类号： H01H9/56 ,  H01H2009/566 ,  Y10T307/951

摘要： An electronic control for gas furnaces controls a two speed main blower fan and an induction draft fan based on inputs from a room thermostat, a high limit and an ignition control including a gas valve. The control has a circuit board having a power supply for providing 24 volts DC current source to drive DC relays and a 5 volt DC power source to power a microprocessor. 24 volt AC input signals are coupled to the input ports of the microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. The output ports of the microprocessor are connected to a relay driver which in turn is connected to relays for energizing and de-energizing the fans.
The control calibrates itself on a continuing periodic basis to read the AC inputs synchronously at the peak of their wave and can switch the relays asynchronously based on the Real Time Clock of the microprocessor or can be switched synchronously by providing a selected delay so that contact engagement and disengagement occurs at or near the zero crossing of the AC line voltage wave form. When used with resistive loads the relays are switched in response to a signal from the microprocessor which is delayed based on the mechanical switching time constant of the relays to provide contact closure and opening at the selected point on the AC line voltage wave form. An alternate embodiment shows a feedback network used to calibrate the specific delay period for each relay upon initialization. When used with inductive loads contact closing can be effected synchronously and contact opening asynchronously.

摘要翻译： 用于气体炉的电子控制器基于来自房间恒温器，上限和包括气体阀的点火控制器的输入来控制双速主风机风扇和感应通风机。 该控制器具有电路板，该电路板具有用于提供24伏直流电流源以驱动直流继电器的电源和5伏直流电源来为微处理器供电。 24伏交流输入信号通过限流电阻耦合到微处理器的输入端口，并通过下拉电阻耦合到交流接地。 交流接地也连接到微处理器的IRQ端口。 微处理器的输出端口连接到继电器驱动器，继电器驱动器又连接到用于为风扇通电和断电的继电器。 该控制器在持续的周期性基础上自行校准，以在其波峰值同步读取AC输入，并且可以基于微处理器的实时时钟异步地切换继电器，或者可以通过提供所选择的延迟来同步地切换，使得接触接合 并且在AC线电压波形的过零点处或附近发生分离。 当与电阻性负载一起使用时，响应于来自微处理器的信号来切换继电器，该信号基于继电器的机械开关时间常数被延迟，以在AC线电压波形上的选定点处提供触点闭合和断开。 替代实施例示出了用于在初始化时校准每个继电器的特定延迟周期的反馈网络。 当与感性负载一起使用时，触点闭合可以同步进行，并与异步开启接触。