零件号：PXI-8423 原产国：美国 可用性：现在有货 条件：全新的 包装：新的原始 保修:12个月 服务:24/7的在线服务 漳州风云提供PXI-8423等DCS/PLC，漳州风云珊妮为您报价，并提供一年保修服务。 PXI-8423质量高价格实惠有多种型号。 The National Instruments PXI-8423/4 (Part Number: 777737-04) is a 4-port, RS-485 Interface Module. Because each match of differential links is a transmission line, the user should effectively end the line to keep away from reflections. A typical technique for termination of a two-wire RS-485 multipoint arrangement is comprised of introducing ending resistors at each finish of the multipoint configuration. If the user interfaces numerous instruments in a chain, then they require an ending resistor just on the first and last instrument. The ending opposition must match the trademark impedance of the transmission line (commonly 100 to 120 Ω). The user can arrange a discretionary DB-9 RS-485 end connector that contains worked in end resistors for simple end from National Instruments.