Rs485 serial

[Tabo260897]

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Hello. I am building a cable to connect beckhoff terminal EL6022 and a Piezo PMD301 motion controller. The connector from EL6022 is a 9Pin Dsub Male. The side of Piezo motion controller is Stereo Jack 3.5 mm TRS cable. The communication set between them is RS485 .
The data sheet of Piezmotor says :
RS485
TRS Function I/O Notes
Tip Data+ In/Out Idle high; 47k to 5V
Ring Data− In/Out Idle low; 23k to 2.5V
Sleeve GND485 GND485 100Ω to GND

For implementing EMC surge protection, refer to Texas Instrumentsdatasheet SN65HVD82. Use standard 3.5 mm stereo plug (TRS).

So i connected TX+ and RX+ in a bridge with the tip and TX- and RX- with Ring and ground with sleeve.
But i could not achieve the communication. Than i saw the Notes but i dont understand them fully.
Should i connect a 47 kOhm resistance at 5 V and than connect it to where (tip or ring ) and 100 Ohm to ground ? I am confused.
I would be grateful to help me to solve this problem.

 

[PN/DP]

Hi

You shouldn't connect any resistors.
Is the serial interface of the EL6022 set to 115kBits/s?
(115200 bits/s, 1 start bit, 8 data bits, parity none, 1 stop bit)
Do the status LEDs Rx/Tx of the interface flicker green and orange?

As a test, swap the wires on the tip and ring (TX+ and RX+ to ring, TX- and RX- to tip).

 

[Tabo260897]

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Yes the parameters COE are correct 115 kBits/s
Led Rx/Tx flicker Green and orange
At the output terminal El6022 in twincat, I can see correct byte values which corresponds with the ASCII string commands sent .
So the comands are sent correctly , but i dont see a movement at the motor, and no feedback values at inputs. So there is an external problem related to cable configuration . I dont know.

 

[PN/DP]

At the output terminal of the EL6022 you will always see the correct bytes, regardless of whether they are connected correctly or incorrectly (or not at all), because you are watching the port and not the signals on the lines. To do this you would have to sniff on the TX+/RX+ and TX-/RX- lines.

You can connect a 120 Ohm bus terminating resistor between TX+/RX+ and TX-/RX- in the DSub connector on the EL6022.
Does something have to be set in the PMD301 controller so that it responds to reception from the RS485?
I don't know more either.