Applies to: SET64RS | XMT634 | PT-238 Temperature Controllers | JLD634
Original manufacturers model designation = XMT634. If you click through to their site use your chrome browser so you can translate the Chinese.
If all you want to do is use one controller connected to your computer then there will most likely be a simpler solution. Go here to see how to retrofit an RS-232 serial port
I started with a serial extension cable from wiredco.com. Click on the photo to see the wiredco.com part. I cut off the female connector and stripped and tinned the Yellow, Orange, Brown and Red wires.
- Orange = Pin #4
- Red = Pin #3
- Yellow = Pin #5
- Brown = Pin #2
Gently remove the case of your Set64rs or XMT634 temperature controller. To open the case: Gently pry on the face plate. Screw driver goes between the face plate and the main body of the case. You can see 2 tangs on the left side of the case ( as you face it > that left ) . Push them in and pry. There are 4 snap in tangs that hold the faceplate to the circuit card assembly by 4 plastic tangs. The faceplate and circuit card assembly will thus come out as a unit.
Fish the wire end of the cable through the hole in the back panel of the case as shown below. Leave a loop of cable so you can remove the case in the future without having to wrestle the wiring.
Solder connect the wires as shown below in both photo and schematic.
 
On the other end of the cable is where I placed the chip that turns the single ended signal of the controllers microprocessor into a double ended signal compatible with RS-422. The chip is an SN75c1167 I adapted an RS-232 to RS-422 circuit card that I designed for a different project. Its simple enough circuit you might be able to do something inside the case or hanging by wires. Be resourceful. You can see the schematic below.
The side labeled "Computer Side" is now ready to be wired to an rs-422 adapter. I used an HXSP-2108G.
- Tx+ goes to pin 9 of a mating D connector
- Tx- goes to pin 5
- Rx+ goes to pin 6
- Rx- goes to pin 1
Other Methods
The above method will only allow the running of a single controller on a port because the TX_EN signal was not wired up to tristate the transmit data coming back to the controller. This implementation was used because I had all the parts available. I needed to prove that people who had purchased SET64RS controllers would be able to retrofit and subsequently be able to use the software I wrote. Communication was proven.
Now I need someone who wants a copy of the software in trade for providing documentation of a better retrofit method. A simpler method would be to wire up a prefabricated Maxim MAX232 board. You can find them on ebay
How to wire up your Set64rs, XMT634,Pt238
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