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泛美公司生产的22DL型测厚仪(以下简称22DL)性能稳定、便于携带、操作简便,深受无损检测工作者的青睐。其实,22DL还配备了RS-232C串行接口,通过该接口,可以实现22DL与计算机之间的数据通信。具体地说,可以用计算机遥控22DL;也可以在结束22DL工作后,把它存储的测试数据(≤1000个)传送到计算机硬盘里,以供进一步分析处理。计算机的介入带来的好处是显而易见的,减少了笔记测试结果过程中产生的误差,降低了劳动强度。本文讨论数据通信过程中的一些具体问题。1 硬件基础一般而言,数字设备输入输出的信号与RS-232C标准兼容。22DL的信号输出范围是±5.5V,信号输入范围是±20V,较大的信号输出范围是出于安全方面的考虑。在22DL的异步串行接口的电器性能中,数据传输速率和最大传输距离这两个相关指标也是非常重要的。数据传输速率越高,最大传输距离就越短;反之亦然。22DL提供的数据传输速率最大为9600bit/s,但一般不用这么大的值。一个完整的RS-232C接口有22根引线,使用25芯插座。但实际上许多生产厂家仅支持RS-232C标准信号中的一个子集。22DL仅使用6根引线,既可以使用9针插座,也可以使用25芯插座。每根引线的定义见附表。22DL的接口除提供数据的输入输出线以外,还提供三条硬件握手线,即RTS——请求发送,如
Pan-American company’s 22DL-type thickness gauge (hereinafter referred to as 22DL) stable performance, easy to carry, easy to operate, by nondestructive testing workers of all ages. In fact, 22DL is also equipped with RS-232C serial interface, through the interface, you can achieve data communication between the 22DL and the computer. Specifically, you can use the computer remote control 22DL; can also be the end of the work 22DL, it stored test data (≤ 1000) sent to the computer hard drive for further analysis and processing. The benefits of computer intervention are obvious, reducing the error generated during the notes test results, reducing labor intensity. This article discusses some of the specific issues in data communications. 1 Hardware Basics In general, the digital input and output signals are compatible with the RS-232C standard. 22DL signal output range is ± 5.5V, the signal input range is ± 20V, a larger signal output range is for safety reasons. In the 22DL asynchronous serial interface electrical performance, the data transfer rate and maximum transmission distance of these two related indicators is also very important. The higher the data transfer rate, the shorter the maximum transfer distance; and vice versa. 22DL provides the maximum data transfer rate of 9600bit / s, but generally do not have such a large value. A complete RS-232C interface has 22 leads, using a 25-pin socket. In fact, many manufacturers only support a subset of the RS-232C standard signals. The 22DL uses only 6 leads, either a 9-pin socket or a 25-pin socket. The definition of each lead see the attached table. 22DL interface in addition to providing data input and output lines, but also provides three hardware handshake line, RTS - request to send, such as