Question: How do I connect a DS100B to a GigaTMS Con485 device?
Answer: The Con485 is a converter between RS232 and RS485 produced by GigaTMS. This article covers how to connect it to the DS100B for testing purposes.
First, set a baudrate on the Con485. For example, select 9600.
Make sure this baudrate is set also for the DS. This can be done in settings, or using on-the-fly commands when you open the connection.
Flow Control must be “Idle or Remote”, since there is no RTS/CTS in RS485.
Next, make sure “serial interface” is “2- automatic”.
Set SW1 and SW2 on the back of the DS100B to ON.
Reboot the DS.
Attach a TB100 adaptor to the DS100B.
RS485 consists of two wires: + and -. There is no ground. TB100 allows for a 4-wire interface - full duplex with two pairs, TX+/- and RX+/-. But Con485 requires only two wires. So, for the DS100B to work properly, you need to connect RX+ to TX+ and RX- to TX-. This turns a 4-wire interface into a 2-wire interface. To do this, just turn on SW1 and SW2 on the TB100, and you're done.
Now all you need to do is connect the TB100 to the Con485 using two wires. On the screw pins of the TB100 you will find TX+/- and RX+/-. Since SW1 and SW2 is on, we only need to connect one of these pairs. Connect RX+/-, for example. These are pins 6 and 7.
So, take two wires and connect this RS485+ and RS485- of the Con485. Plus goes to plus, minus goes to minus.
That's it for the 485 connections. Simple!
The next step is to connect the Con485 to the RS232 port of the computer, to see if it works. This sounds trivial, but you should really pay attention to the RX/TX pin assignment on the Con485, because on this specific device it can be a bit confusing. Read the manual carefully! Make sure you connect the TX of the Con485 to the RX of the computer, and the RX to the TX.
You should now be able to run HyperTerminal and see it work.
This is because the line is not terminated in this example. Rs485 lines should be properly terminated. On the TB100, just turn ON switch 5 or 6 (but not both!). Now you have to make sure the other end of the line is proerly terminated.
Then buy one!
Seriously – it will make your life much easier when creating such setups. It's not an expensive connector.
If for some reason you really can't buy one, then use a female DB9 connector and solder the lines – RX- to TX- and RX+ to TX+ according to the DS100B pinout here. But then you'll have a problem with termination for longer-distance lines – you will have to solder in the termination components yourself. We really advise working with a TB100.
We wish to thank our partner IDP for finding and helping correct technical errors above.
