Matrix Orbital Corp

Hello,

I'm current looking to use these devices in a mobile application and communicate with a PLC.

I have 2 Extended Range displays here, ones a VFD and a PLED.

My problem lies in the communication.

I have failed several attempts to communicate with either of these displays over RS-232.

My oomm link has been tested and works. And both displays I used the jumper to set to default settings which should be 19.2kbps Baud..

Here are my questions....

Since these are extended range, (+9 to +15)

1) If the jumpers are set for RS-232 and this is a +9V to +15V Display does my sender need to send in +-12V RS-232?
(Could not communicate with Laptop - Laptop would be 0V-5V)
(Tried both the 9-pin D-Sub and RX/TX lines)

2) I tried setting one of the displays to TTL (0V to 5V)
(Could not Communicate with Laptop)
(Tried both the 9-pin D-Sub and RX/TX lines)

3) The manual says nothing of default Stop Bits or Parity?? only Baud

4) Is the 9-Pin socket always TTL? does it change from with the jumpers?
or do the jumpers only control the RX/TX lines?

5) Where is the jumpers for deciding what input its using? The 9-pin or RX/TX??? How do I know what Voltage levels are need for each of these??

Thanks,

Hi ShadowRam,

Welcome to the LCD forums!

After reading about the problems that you are experiancing, I have a number of questions for you:

1. What are you using to power the displays?
2. Have you tested the displays using a PC?
3. Does the display appear to power on properly?
4. What type of cable are you using to communicate with the display?

I will try to answer the questions that you have asked as well:

1) If the jumpers are set for RS-232 and this is a +9V to +15V Display does my sender need to send in +-12V RS-232?
(Could not communicate with Laptop - Laptop would be 0V-5V)
(Tried both the 9-pin D-Sub and RX/TX lines)

As far as I know laptops use standard RS-232 communication (+-12V), and not TTL communication (0-5V). However after a quick internet search I've found that:

"Some older IBM Think Pads had comm ports that did not meet the true RS-232 specifications for data transfer. They operated at slightly different voltage ranges. The solution here is a ?Black Box? from IBM. This box converts the voltages to the correct levels."

2) I tried setting one of the displays to TTL (0V to 5V)
(Could not Communicate with Laptop)
(Tried both the 9-pin D-Sub and RX/TX lines)

This comes back to q1. One thing that I would like to recommend is that you get a null modem cable and connect it from your laptop com port to a pc com port, and then monitor your pc com port with a program such as hyper terminal. This will give you a good idea wether the laptop is transmitting the proper signals.


3) The manual says nothing of default Stop Bits or Parity?? only Baud
Stop bis/parity won't effect wether the display shows your information or not, but for now use 1 stop bits, and no parity. (changing these values will simply cause garbage to display on your screen. This is the same as the baud rate, if you have an incorrect baud rate, you will see garbage, not nothing)

4) Is the 9-Pin socket always TTL? does it change from with the jumpers?
or do the jumpers only control the RX/TX lines?

The jumpers effect both the DB9 and 4-pin header.

5) Where is the jumpers for deciding what input its using? The 9-pin or RX/TX??? How do I know what Voltage levels are need for each of these??

There are no jumpers, the different connections are provided as alternative methods of communication. Therefore if you are sending communication to the 4-pin, you will not need to send communication to the 9pin, and vise versa. However, they may be used in conjunction where you would suppy power to the 4-pin and provide the communication to the 9pin.

This is very interesting thanks,

"Some older IBM Think Pads had comm ports that did not meet the true RS-232 specifications for data transfer. They operated at slightly different voltage ranges."

As it was a IBM Thinkpad that was being used.

1) I'm using 12V from a Computer Power Supply.

2) No, I haven't tried from a PC, (Although I will now, that I know about the Thinkpad issue)
Using HyperTerminal, the ThinkPad was able to Communicate to the PC.
Which I ruled out if the Laptop was outputting anything in the correct BAUD and that the cable was ok.

3) The Display does display properly. Matrix Orbital Default screen does come up.

4) Serial Cable (Female to Female) with a Gender Bender (Male to Male) to connect the Display to the LapTop.


So I guess tonight, I'll hook it up to my PC instead of the Laptop and try that.

On a side note, I must of damaged the VFD.
It used to power up properly and show the default screen.
But since I set it for TTL and I tried communicating to it with RS-232,
Now it doesn't power up properly anymore. :/

Thanks for the Helpful Information!, I'll post if I get the PLED running.

(Quick Question, why not have actual jumper pins for Protocol Selection instead of trying to do pin-point soldering?)

I am sorry to hear that while trouble shooting this issue you damaged the module and I can defenetly confirm that using RS-232 communication in TTL mode will damage the display. Please email me at jklassen@matrixorbital.ca and we can talk about repairing the display.

I will await your results on using the PLED with your computer.

--
Jon