這PXI國(guó)家儀器公司NI-6704(零件號(hào):777796-01)是一個(gè)模擬輸出模塊，可用于創(chuàng)建軟件定時(shí)電壓和電流輸出應(yīng)用。用戶可以自主設(shè)置各通道的輸出電壓范圍。這PXI-6704還集成了8條數(shù)字5 V TTL/CMOS I/O線路。

這倪PXI-6704具有一個(gè)時(shí)分復(fù)用的16位DAC，以構(gòu)成所有輸出通道。每個(gè)通道都有一個(gè)采樣保持電路，以保持DAC更新之間的通道值。在該模型中，DAC通過(guò)多路復(fù)用產(chǎn)生16路電壓輸出、16路電流輸出和4個(gè)校準(zhǔn)通道。板載溫度傳感器測(cè)量流經(jīng)電路板的空氣溫度。該傳感器靠近片上精密基準(zhǔn)電壓源，會(huì)受到異常溫度的影響。這種傳感器有一個(gè)串行計(jì)算機(jī)接口。

這倪PXI-6704執(zhí)行持續(xù)自校準(zhǔn)。此外，除了可訪問(wèn)的模擬輸出通道之外，還有內(nèi)部校準(zhǔn)通道，它們與所有輸出通道一起被掃描和刷新。輸出電壓有兩個(gè)校準(zhǔn)通道:電壓失調(diào)通道和電壓增益通道。

上的電流輸出還有兩個(gè)校準(zhǔn)通道PXI-6704:電流偏移通道和電流增益通道。這些校準(zhǔn)通道的輸出分別與片上基準(zhǔn)電壓源進(jìn)行對(duì)比，并調(diào)整16位DAC失調(diào)和增益，以將調(diào)整通道中的誤差降至最低。自從倪PXI-6704失調(diào)和增益誤差具有出色的通道間匹配，限制對(duì)準(zhǔn)通道中的誤差同樣可以將所有電壓和電流輸出的誤差降至最低。

The National Instruments NI PXI-6704 (Part Number: 777796-01) is an Analog Output Module, which can be used to create software timed voltage and current output applications. The user can autonomously set the output voltage range on each channel. The PXI-6704 also incorporates eight digital 5 V TTL/CMOS I/O lines.

The NI PXI-6704 has one 16-bit DAC that is time-division multiplexed to make all the output channels. Each channel has a track-and-hold circuit to keep up the channel value between DAC updates. On this model, the DAC is multiplexed to create 16 voltage outputs, 16 current outputs, and four calibration channels. The onboard temperature sensor measures the air temperature flowing over the board. This sensor is situated close to the onboard precision voltage reference, which can be influenced by extraordinary temperatures. This sensor has a serial computerized interface.

The NI PXI-6704 performs persistent self-calibration. Additionally, to the accessible analog output channels, there are inside calibration channels that get scanned and refreshed alongside all the output channels. There are two of these calibration channels for the output voltage: the voltage offset channel and the voltage gain channel.

There are additionally two calibration channels for the current output on the PXI-6704: the current offset channel and the current gain channel. The outputs of these calibration channels are individually contrasted to onboard references and the 16-bit DAC offset and gain are adjusted to minimize the mistakes in the adjustment channels. Since the NI PXI-6704 has excellent channel-to-channel matching of offset and gain errors, limiting the errors in the alignment channels likewise minimizes the mistakes for all the voltage and current outputs.