RJ45 to RS485 pinout

Lilith

Member
Join Date
Apr 2011
Location
NA
Posts
6
Hi guys!

I'm trying to build a cable to connect twido plc (RS485) and altivar71 (RJ45). Anyone knows pin-out for this connection? Does it matter which ethernet cable i use (a or b, images attached)? Thanks!

typea.jpg

typeb.jpg

rs485.jpg
 
It should be a fairly easy connection. It doesn't matter which type of Ethernet cable you use since the RJ-45 connector doesn't actually use Ethernet at all, and you only need positions 4 and 5 which are the same colors on both types. You'll connect the blue and blue/white pair to terminals A and B on the Twido. You'll have to try both polarities to determine which is correct.
 
So i don't need to use the third pin (SG) on rs485 connector? I will try that, thank you very much! :)
 
If you have any issues, connect the brown wire from the Ethernet cable to SG.

Thank you, i've made the cable but i'm still unable to start the motor. I use following devices:

HMI XBTGT 4330 7"
Programming software: VijeoDesigner 4.6.0.7613

Twido PLC TWDLCAE40DRF
Programming software: TwidoSuite 2.0

Altivar 71

Ethernet communication between HMI and PLC works fine, i can set the speed on HMI and correct value is displayed in animation table on PLC. I used following settings on Altivar:

Communication - Modbus Network:
Address: 2
Baudrate: 19200
Data bits: 8
Time between frames: 10
Command: Ref.channel 1: Modbus
Ch1 active
Profile Not separ.

System word %SW64 keeps returning (modbus) error code 8. I have NST message on Altivar with these settings; if I try to use I/O profile it says RDY but does not receive anything from PLC, or returns CRC 2. I've read manuals, checked wiring and tried pretty much everything I could think of, but no luck :(

HMI and Twido programs are included in attachment. I would be very grateful for any suggestion regarding this issue. Tyvm!
 
Looking over your Twido program I have noticed that both RS485 ports (mini-din) and the terminal block option block share the same Modbus address of 1.
 

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