Author Topic: ROV control  (Read 1577 times)

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Offline Edwin the inductorTopic starter

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ROV control
« on: March 05, 2020, 03:28:11 pm »
Hello
I working on a ROV (remote operating vehicle) I'm hav com to the contorol. I wonder can I use a Arduino with TX RX?
the cable is 50 m or should I use rs232? and if I use rs232 how should I do it (I'm bad on programming)?

grateful for help.
 

Offline i_am_fubar

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Re: ROV control
« Reply #1 on: March 05, 2020, 07:16:44 pm »
Depends what you need to control. If just forward backward and you have a cable, run multiple telemetry lines?
 

Offline johankj

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Re: ROV control
« Reply #2 on: March 06, 2020, 09:22:31 am »
If you want to use serial communications:

Keep you baud-rate low, like 9600. That is a good trade-off between speed and transmission quality.

If you are using the serial-line of an arduino, that is a 3.3V or 5V line. Over 50m you may have an issue.

If you use a RS232-chip (like MAX2323), the chip usually bumps the voltage up to +/- 12V. You can easily communicate over 50m at low baud rates.

Have a look at the data sheet: http://www.ti.com/lit/ds/symlink/max3232.pdf

You would have to have something like an Arduino in both your top-side controller and your ROV.
 

Offline Pack34

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Re: ROV control
« Reply #3 on: March 09, 2020, 02:43:21 pm »
RS485 may be your best bet. It'll handle longer cable runs than RS232
 
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Offline fcb

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Re: ROV control
« Reply #4 on: March 09, 2020, 03:04:37 pm »
As Pack34 says: RS485

Good for 4KM.  You can use it in half-duplex or simplex (one pair) or full duplex (two pairs).  Speeds for 500M can be quite quick, easily 115K2.
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Offline johankj

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Re: ROV control
« Reply #5 on: March 11, 2020, 09:10:54 pm »
Agree, RS485 is definetivly more robust, but for 50m, I don't think it matters. Unless he needs higher baudrates?
 

Offline james_s

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Re: ROV control
« Reply #6 on: March 11, 2020, 10:39:20 pm »
RS485 is the way to go, it's not even going to be appreciably more expensive than real RS232 with proper levels. RS485 is specifically designed for this sort of communication.
 

Offline johankj

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Re: ROV control
« Reply #7 on: March 12, 2020, 08:43:48 am »
I don't disagree, but RS232 is simpler and solves his problem.
 

Offline fcb

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Re: ROV control
« Reply #8 on: March 12, 2020, 10:39:44 am »
I don't disagree, but RS232 is simpler and solves his problem.
He won't be using proper EIA232 voltage levels if he has an arduino - only RS232 packet structure e.g. 8N1.  The levels will be at best 5V and 0V.

You could make this run many hundreds of meters at quite high data rate - if you match impedances between the launch, cable and receiver... If the ROV is battery powered then OK, if it is powered by the umbilical, then the OP needs to understand ground lift, noise, etc.. Or just use a pair of $0.50 RS485 transceiver ICs and twisted pair and be golden.

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Offline johankj

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Re: ROV control
« Reply #9 on: March 12, 2020, 11:19:31 am »
I don't disagree, but RS232 is simpler and solves his problem.
He won't be using proper EIA232 voltage levels if he has an arduino - only RS232 packet structure e.g. 8N1.  The levels will be at best 5V and 0V.

You could make this run many hundreds of meters at quite high data rate - if you match impedances between the launch, cable and receiver... If the ROV is battery powered then OK, if it is powered by the umbilical, then the OP needs to understand ground lift, noise, etc.. Or just use a pair of $0.50 RS485 transceiver ICs and twisted pair and be golden.

Yes, I've pointed this out, and also suggested a suitable RS232 chip.

He's running 50 metres of cable, under water presumably, hence I claim doesn't matter which one he uses.
 

Offline james_s

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Re: ROV control
« Reply #10 on: March 12, 2020, 08:23:04 pm »
I don't disagree, but RS232 is simpler and solves his problem.

How is it simpler? The hardware is virtually identical, actually I'd say the hardware is simpler, the level shifter IC doesn't require any charge pump capacitors. Cost is similar, cabling requirements are essentially the same, it only requires different ICs at each end.
 

Offline johankj

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Re: ROV control
« Reply #11 on: March 13, 2020, 06:44:29 am »
I don't disagree, but RS232 is simpler and solves his problem.

How is it simpler? The hardware is virtually identical, actually I'd say the hardware is simpler, the level shifter IC doesn't require any charge pump capacitors. Cost is similar, cabling requirements are essentially the same, it only requires different ICs at each end.

Because it is half duplex, and OP is like:
Quote
I'm bad on programming)
 


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