What cable can I use for communication using TTL to RS485 Module?

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1

I'm using the TTL to RS485 Module as shown below. I want to connect 2 slaves to the master with a distance of 5-7 meters and use the RTU modbus library. I'm still confused about the cable that can be used. Can I use a cable like the picture below? Please give me suggestion and information about this?

Thanks

RS485 MODULE
d278d8ff-78c4-4814-86b7-4571cc8b6d14

Can i use this cable?

Screenshot (70)
Screenshot (70)1366×768 232 KB

If it can be used, how many cables are needed to connect between slave and master?

2

Hi,
Google;

rs-485 cable diy

Even cat 5 twisted pair will work.

Tom.. :smiley: :+1: :coffee: :australia:

3

remove the terminator on the slave nearest the master, this is R7 on the module. And use twisted pair cable

Is perfect.

basically 2 (1 twisted pair)

4

Hi,
This should help;

Tom.. :smiley: :+1: :coffee: :australia:

5

So...any suggestions for cables I can use? like what brand and others?

[image]

6

314724895_6065198976842476_2546230570128154787_n
314724895_6065198976842476_2546230570128154787_n640×1422 93.3 KB

How about this? can it be used?

7

yes, but use a pair for A & B , so Brown & Brown-White or Orange & Orange-White etc.
Though for the 7 meters it won't matter too much, but having thin wires with low capacitance is the way to go, so yes use UTP cable

8

Sorry, maybe this is a very basic question. But I'm still confused, in the picture above, there are 4 wires namely red, green, white and black and there is also a ground. I'm still confused about connecting anywhere because there are only 2 pins, namely A B to connect the slave, while in the picture above there is ground. Can you explain it to me?

And for ground connected to which ground?

Thanks

9

I'm afraid to buy the wrong cable that I need, moreover, the price is quite expensive for me

10

Hi,
If you use Cat data cable, when you pull back the outer cover and the shield, you will see the pairs appear as below.

image
image640×640 91.9 KB

Each pair is twisted together.
Note the colours.
You would only need to use one of the pairs for A and B.
For example the Orange wire and the White/Orange wire are a pair.

The reason we suggest cat cable is the convenience of having it ready twisted, which is ideal for 485 needs.

Tom.. :smiley: :+1: :coffee: :australia:

11

Ok...if I buy the cable like the picture I posted above and I twist the white-green and black-red like the picture below. Then, white-green to pin A and black-red to pin B. Can it be like that? sorry if im wrong.

And for the ground connected to which ground? ground module rs485 or ground microcontroller?

Screenshot_20221118-134737
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12

Hi,
The cable you have shown has four twisted pairs, I think, you only need one.

BLACK and RED will do.

Put A on the RED wire and B on the Black wire, you do not have to twist anything, RED and BLACK are already twisted together.

Leave the other three pairs ( four wires ) alone.

Tom... :smiley: :+1: :coffee: :australia:

13

Oh...I see.
I might ask this last question to be sure.

Which of the 2 pictures below do you think is more appropriate?

And how about ground? Do I need a grounded cable?

Screenshot_20221118-151236
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Screenshot_20221118-151223
Screenshot_20221118-151223720×1600 93.8 KB

14

Neither of those cables are twisted pair.

Yes you can use shielded to gnd.

Tom... :smiley: :+1: :coffee: :australia:

15

the seller said the 2nd picture is twisted.

To ground my Rs485 module or ground my microcontroller?

16

Good question.

image
image919×411 55.7 KB

Tom.... :smiley: :+1: :coffee: :australia:

17

Okay...thank you very much for the information you have provided. Nice to discuss with you. :grin:

18

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