Hypertherm board pinout for RS485 extension board

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20 Oct 2020 22:29 #186761 by snowgoer540

OK, just returned from the workshop and I couldn't get any communication on J11 (expected RS232)

Connection tested using serial params 19200,8,EVEN,1, I've tried several ModBus ASCII apps, even sending a single command as per serial reference doc - no response from the plasma unit.

I think the issue might be in "ENABLE SIGNAL". I've tried to leave it not connected, supply 3.3V to it or connect it to the ground - no joy.
Are there are any proud owners of RS485 board here who have any electronic knowledge and are willing to check how this signal is connected on the original board?

Maybe I've gotten lost in the thread... but what exactly are you trying to achieve?

Initially, I was expecting that data available over ModBus / serial link might be sufficient to make PlasmaC act as THC (e.g. by reading arc voltage and adjusting torch hight). That was clarified by Tommylight as a not appropriate approach.

Looking on the pinout make me curious and check if signals on connector J11 on the mainboard are RS232 (3.3V TTL to be more specific) and if those signals can be used for ModBus coms without the original extension board.


Maybe over the weekend I'll see if I cant take my PMX apart and get you a pic of the RS485 board. Not sure if it would help or not. But it would be interesting if this really was just a 232 to 485 converter.

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20 Oct 2020 22:34 #186763 by snowgoer540
as I recall though the board is covered in a thick conformal coating.

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18 Apr 2021 11:02 #206293 by radek_marko
I have revisited this project with a direct RS232 TTL 3.3V to USB converter to eliminate RS485 element from the equation, but still no luck :(.


Looktween thing on the pinout I'm wondering - why the pin +3.3V is called "INPUT". Using multimeter I've checked that there is +3.5V between this pin and the ground.

Does anyone have a faulty Hypertherm board and can trace those pins?
Attachments:

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18 Apr 2021 11:19 #206294 by rodw
I always wondered how the enable worked. I figured it was to do some kind of handshaking between the Hypertherm RS232 board and the machine to prevent bypassing their hardware.

There is an interesting little board here www.mikroe.com/rs485-3-click
It presents the correct RS485 pins It might be possible to get one of these working.

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18 Apr 2021 12:15 - 18 Apr 2021 12:15 #206298 by PCW
Enable is most likely the RS-485 transmit-enable signal
Its _probably_ active high. This is required for 2 wire
(1/2 duplex) RS-485 connections.
Last edit: 18 Apr 2021 12:15 by PCW.

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18 Apr 2021 13:20 #206305 by bevins
Why does the hyperterm use full duplex 4 wire rs485. This is only to set amps etc? can we get ark ok and voltage from the 485?
I thought it was only for setting the parameters for powermax.

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18 Apr 2021 16:19 - 18 Apr 2021 16:20 #206313 by PCW
The Hypertherrn interface is bi-directional you can set various parameters but also
read status and fault conditions.

Note that both 2 and 4 wire RS-485 interfaces are bidirectional, but only 4 wire
interfaces can transmit and receive at the same time (full duplex). 2 wire interfaces
transmit and receive on the same pair so must disable the transmitter when receiving
(1/2 duplex) Kind of like "push to talk"
Last edit: 18 Apr 2021 16:20 by PCW.
The following user(s) said Thank You: bevins, rodw

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18 Apr 2021 20:56 #206337 by rodw

This is only to set amps etc? can we get ark ok and voltage from the 485?


The high end Hypertherms publish everything to the Ethernet BUS. So you don't even need to read the torch voltage. Its on the BUS.

good luck with the upgrade though! B)

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18 Apr 2021 21:30 - 18 Apr 2021 21:31 #206339 by robertspark

......can we get ark ok and voltage from the 485?
...


no (Comms too slow)

all adjustable / setable or readable parameters in the manual

www.google.com/url?sa=t&source=web&rct=j...&cshid=1618781490208
Last edit: 18 Apr 2021 21:31 by robertspark.

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18 Apr 2021 21:57 #206342 by rodw

Enable is most likely the RS-485 transmit-enable signal
Its _probably_ active high. This is required for 2 wire
(1/2 duplex) RS-485 connections.


If thats the case a Texas Instruments SN65HVD34 would probably work as it has the required TX enable pin.
www.mouser.com/Texas-Instruments/Semicon...jc?P=1yxz5msZ1z0zls6

The SN65HVD31 chip used on the board I shared is more for a simpler UART with just TX and RX.

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