What is RS485 and How it's used in Industrial Control Systems? — Transcript

Full transcript

1. 0:00welcome to another informative video
2. 0:03brought to you by real pars today you
3. 0:07will learn about rs-485 if you're
4. 0:11familiar with rs-232 then you may
5. 0:13already know a little bit about it if
6. 0:16not check out our other video
7. 0:19what is rs-232 the link will be provided
8. 0:22below
9. 0:26[Music]
10. 0:36before we get started on today's video
11. 0:38if you love our videos be sure to click
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16. 0:51one
17. 0:54just like its older brother rs-232
18. 0:58rs-485 is a form of serial communication
19. 1:02think of rs-485 as the younger faster
20. 1:05brother of rs-232 what made it such an
21. 1:10advancement over rs-232 was the fact
22. 1:13that it could transmit not only a single
23. 1:15device to device transmission but also a
24. 1:18communications bus to connect multiple
25. 1:21devices at once
26. 1:25the configuration and specifications of
27. 1:27rs-485 make it faster and extend the
28. 1:31range of data transmission
29. 1:34you aren't limited to 50 feet of cable
30. 1:36like with rs-232 the maximum cable
31. 1:40length for rs-485 is typically listed as
32. 1:431,200 meters or about 4000 feet
33. 1:48much like rs-232 rs-485 doesn't have an
34. 1:52actual standard connector many times the
35. 1:56old db9 connector is used
36. 2:00in some applications terminal strips
37. 2:02were used in place of a connector this
38. 2:05helped rs-485 become a widely used and
39. 2:08very versatile form of serial
40. 2:10communication
41. 2:13another advantage over rs-232 that I
42. 2:16mentioned earlier is the number of
43. 2:19connectable devices rs-485 can handle up
44. 2:23to 32 connected devices rs-232 could
45. 2:28only handle one this allowed users and
46. 2:31manufacturing facilities to connect
47. 2:33larger applications and whole machines
48. 2:35with one protocol
49. 2:39another +4 rs-485 is that it is less
50. 2:43susceptible to noise issues Electric
51. 2:46noise can cause all kinds of problems
52. 2:48for electronics rs-232 reference ground
53. 2:52to decipher the data it was transmitting
54. 2:55this allowed for electrical noise to
55. 2:58cause interference
56. 3:01rs-485 avoids this issue which also
57. 3:04allows for shielding of the cables to
58. 3:06prevent noise
59. 3:08you may be wondering what can I do with
60. 3:11serial communications especially rs-485
61. 3:16one very common example in the
62. 3:18automation world is remote control of
63. 3:21VFDs or variable frequency drives many
64. 3:25people just call them motor drives
65. 3:29a simple network of a PLC VFD and an HMI
66. 3:34allows remote control of motors in an
67. 3:37industrial setting
68. 3:41let's say you were monitoring a water
69. 3:42pump filling a vessel you decide that
70. 3:45the water is not filling fast enough to
71. 3:47keep up with demand with your rs-485
72. 3:51network you can remotely monitor and
73. 3:53control that pump from a control center
74. 3:56this is possible since the HMI is
75. 3:59connected to your PLC via rs-485 the plc
76. 4:04is also connected to the VFD via rs-485
77. 4:10the PLC is programmed to monitor the
78. 4:12level of the water in the vessel it also
79. 4:16allows manual flow control if needed all
80. 4:19of this allows you to speed up the VFD
81. 4:22that controls the speed of that water
82. 4:24pump problem solved thanks to rs-485
83. 4:28communications
84. 4:32about what we now know about rs-485 it
85. 4:36is faster and much more versatile than
86. 4:39the older rs-232 users can utilize a
87. 4:44longer cable up to 1200 meters or about
88. 4:474,000 feet
89. 4:50the greatest feature of rs-485 is the
90. 4:53fact that you can connect up to 32
91. 4:55devices on one system rs-232 could only
92. 5:00handle one at a time
93. 5:03there is no standard connector for the
94. 5:05protocol most manufacturers still
95. 5:08utilize a db9 connector
96. 5:11you can also still simply use a terminal
97. 5:13strip this makes utilizing rs-485 simple
98. 5:18all-in-all rs485 really allowed full
99. 5:21automation possible with its ability to
100. 5:24connect so many devices at once
101. 5:27I truly hope this video is helpful
102. 5:29please don't forget to check back later
103. 5:31for more real Parrs videos
104. 5:35make sure that you head over to real
105. 5:37parse comm to find even more training
106. 5:40material for all of your plc programming
107. 5:43needs we offer many videos to assist you
108. 5:46in learning plc programming and landing
109. 5:49that job in the high-paying highly
110. 5:51sought after field of automation and
111. 5:53controls engineering go to real parse
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114. 6:01[Music]