Basic RS485 connection to the computer

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js1156
Posts: 4
Joined: Mon Feb 08, 2016 12:46 pm

Basic RS485 connection to the computer

Postby js1156 » Wed Apr 06, 2016 2:27 pm

Hello, I would like to know how to establish basic communication with the computer and the LRD507-KD driver .
I am connecting 1 driver to 1 computer. I'm hoping to make LabVIEW on the computer be the master, the driver will be the slave in Modbus protocol.

So far I have done these things:
Set SW1 to 1.
SW2 to 9600 baud. (only switch 4 is on).
and
Set both SW3 switches to off.
Then I connected CN6 to an RS485->RS232 converter then a serial RS232 connector to the USB on the computer.

As usual CN1 is set to the DC power supply and CN4 to the motor itself.
I also kept the CN3 communication to the PC. I tried to communicate the driver and computer with and without CN3 connected.
I double checked the baud rates and parameter settings on the computer and driver in accordance with the this manual: http://www.orientalmotor.com/products/p ... 112-7E.pdf
I tried to test the connection on NI MAX before testing it on LabVIEW. So far, no luck. I have a red blinking Alarm LED and red lit C-ERR LED, but the C-DAT led isn't lit at all.
I also got a communication error 84 when testing RS485 on MEXE02.
By any chance, would anyone know how to troubleshoot this? And is there any way to test if the converter is working? I think this driver is the only RS485 device we have.
Thanks in advance!

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om_tech_support_JT
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Location: Torrance, CA
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Re: Basic RS485 connection to the computer

Postby om_tech_support_JT » Mon Apr 11, 2016 9:16 am

Sorry we do not support Labview. However, from experience, a download of the Labview Modbus RTU library is required for proper communication. Please see below:

http://www.ni.com/example/29756/en/

Your switch settings seem to be correct for 9600 baud rate, ID=1, Modbus protocol ON. The 84h alarm refers to a RS-485 communication error. Please also check other communication settings such as parity and stop bit. The settings have to be the same as your master.

Network converters are not easy to troubleshoot. I'd try another one if you have one. Make sure the software driver for the converter is installed and working.

See PAGE 103 of the user manual for more info:
http://www.orientalmotor.com/products/p ... 112-7E.pdf

Here's a freeware that we sometimes use to test Modbus RTU communication. Perhaps you can try this too:
http://www.softpedia.com/get/Network-To ... -Pro.shtml

js1156
Posts: 4
Joined: Mon Feb 08, 2016 12:46 pm

Re: Basic RS485 connection to the computer

Postby js1156 » Mon Apr 18, 2016 8:20 pm

Hello again,
We bought a new converter and tested it.
I used the converter software to send messages to the driver.
The driver seems to take the messages. It would blink only the ERR-DAT when the message was sent wrong, but turn off when I resent it correctly, but the motor would not move. So the problem seems to have been the converter, but unfortunately, the motor would still not move.

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om_tech_support_JT
Posts: 1058
Joined: Fri Mar 12, 2010 2:59 pm
Location: Torrance, CA
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Re: Basic RS485 connection to the computer

Postby om_tech_support_JT » Fri Apr 22, 2016 11:29 am

Hi js1156,

You have to set some data such as Position No.1 in steps (lower register address 0403h) or Operating Speed No.1 (lower register address 0503h) before you can command the motor to either move to a specified rotational angle or continuously rotate. The easiest way to command the motor to move is to program the 0503h register to some value for speed in Hz, then turn on the FWD or RVS input for continuous operation with the 1Eh input command register. You can do this by setting the data value of the register address 001Eh to 513 (after setting 0503h to something other than 0).

If you need help doing something else, please let us know.

aldoned
Posts: 32
Joined: Mon Sep 14, 2015 3:03 am

Re: Basic RS485 connection to the computer

Postby aldoned » Sat Sep 03, 2016 10:59 pm

Thanks for the info


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