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标题: 485星型结构，最远距离是多少？ [打印本页]

作者: 绣墩草001 时间: 2006-4-27 09:17
标题: 485星型结构，最远距离是多少？
大家好：PC下面通过232转485转换后挂接10台门禁控制器（不是手拉手方式），如果用星型结构，最远距离能走多远？

作者: 中原来管 时间: 2006-4-27 13:17
说不清.最好不要这样接,用一个485分配器吧

作者: delphi1978 时间: 2006-4-27 22:39
可以走375.4765米

作者: huajian203 时间: 2006-4-28 14:55
485不是能走1200M吗

作者: LFSXHY 时间: 2006-4-29 11:34
同意２楼建议

作者: 三十九度 时间: 2006-4-29 12:51
10条线的距离之和为1200米

作者: 豆儿 时间: 2006-4-29 13:46
星的接法线的总长不要超过１２００米了！

作者: wiegand26 时间: 2006-5-10 13:17
1200M

作者: jack.hu 时间: 2006-6-5 15:26
同意6楼兄弟意见

作者: wiegand26 时间: 2006-6-6 08:38
在1200米的基本基础上,加上一个中继器最多可以走3000多米.

作者: 菩提 时间: 2006-6-7 16:50
典型距离值是1200M,但因为环境情况等各方面原因,实际到不了1200M,我最远用到过1100M

作者: 大海盗 时间: 2006-6-8 07:55
前一阵子看了一篇文章说485传1200米前提是传输线缆是最好的......总线上只有一台485设备.........才可能传输到1200米..........晕..........不知道是真的还是假的????

作者: wiegand26 时间: 2006-6-8 08:36
错误：485总线的通讯距离可以达到1200米. 其实只是485总线结构理论上在理想环境的前提下才有可能使得传输距离达到1200米.一般是指通讯线材优质达标,波特率9600,只有一台485设备才能使得通讯距离达到1200米,而且能通讯并不代表每次通讯都正常.所以通常485总线实际的稳定的通讯距离远远达不到1200米. 负载485设备多,线材阻抗不合乎标准,线径过细,转换器品质不良,设备防雷保护,波特率的加高等等因素都会降低通讯距离.

作者: lylen 时间: 2006-6-8 13:12
加个485HUB分出去吧，理想的话，700米以下没有问题的

作者: lylen 时间: 2006-6-8 13:13
干吗非要走到极限呢，想不通！

作者: fuzhiqian 时间: 2006-6-8 14:52
同意14楼说法！

作者: sdgp 时间: 2006-6-8 23:06
    大家说的都很好,485通讯距离理论上是可以达到1200米(各个分支的总和).我用过科松的分了两条线,带了23个一体机.还挺稳定的.不过刚开始出了点问题,我没有用他们配套的RS485/232转换器,很不稳定,后来又买了他们的,呵呵稳定的一腿!

作者: sdgp 时间: 2006-6-8 23:35
<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">      RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线是一种广泛应用的半双工总线，<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线是一个主站对从站的点对多点网络，<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线通过一对双绞线将现场所有的<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">设备以总线型结构从头到尾连接起来
<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">。但在实际现场应用中，很难用一条总线将所有设备连接起来，现场设备大多是星型、放射型点对多点分布。于是市场上出现了<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">485HUB<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">能将<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线能将<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线变为星型或放射型分布，即将一条<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线变为多条分叉型<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">RS485<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">总线，使<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; 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mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">128<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">个节点，对一般工程应该可以应付了。所以节点的总线总和不超过<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">1200<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">米，本人用过<span lang="EN-US" style="FONT-SIZE: 10pt; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">JaRa<span style="FONT-SIZE: 10pt; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman";">品牌还不错。

作者: wiegand26 时间: 2006-6-9 08:54
专家言：用485HUB，理想下是1200M。实际最远可达800M。公司：深圳市微耕实业有限公司 网址：<a href="http://www.wiegand.com.cn">www.wiegand.com.cn</a> 销售：李佳玉 电话：0755-82501125 传真：0755-82500661 手机：13148822980 MSN:wgxs001@hotmail.com E-mail:wiegand26@126.com

作者: davei 时间: 2006-6-9 14:46
如果真正的是走星型，那你得选用，RS485HUB，而现在的这个设备，参数是3000米，能不能达到这个效果，主是要看这设备的好坏有关，好的厂家加了光隔后，性能真的很好。实际中的距离要根环境和干扰有关，如果按弱电布方式布线，2000米左右不成问题的，我在实际中证实过。

作者: 沉睡的木头 时间: 2006-6-10 09:32
485理论值传输距离是1200米,工程实际传输距离一般是在1000米左右.这是RVV传输.网线还达不到1000米

作者: xinhan79 时间: 2006-6-10 10:12
485的线缆要是可以做星型的那可以节约多少线啊！分配器的价格大概是多少！发一个报价什么来看看  谢谢先！！xinhan79@163.com

作者: davei 时间: 2006-6-10 18:12
木头，RS485HUB，不说3000米，2000米绝没问题，上楼，RS485HUB有分四口和八口，价格在1000多元，牌子不回，价格一定的差距，如你有需，可以跟我联系

作者: sungel88 时间: 2006-7-9 22:01
恩,是有点问题.实际是达不到的显周电子:QQ477978038021-54142942/54168512

作者: yangrw 时间: 2006-7-10 11:33
如果每根1200米的话，你的通信速度会很慢很慢

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