Help With Robotics Project

I'm working on a robotics project and I'm having trouble sending commands to my relay module. The device is a Weeder technologies WTSSR-M. I have successfully connected the relay to my computer using a USB-RS232 adapter. I am using the Tera Term Pro application for my serial termial. I can send commands to the relay and get a response from it.

When I try to send a command sequence the device responds immediately after I type the first character of the command. I'm supposed to start every command sequence with the address of the device (A) and end the command with a carriage return (enter key). For some reason the sequence is going directly to the device before I press the carriage return.

For example, when I try to send the following sequence which tells the relay to close the first switch for 1/2 second:

AC10000500

the device responds with A?

As soon as I type the first letter of the command the device responds with the error character "?". I don't get a chance to complete the command.

Thanks in advance for your help.

I'm not an expert on robotics, and I'm not familiar with the device you're using, but it sounds like you need to program your URAT to buffer the command before forwarding it. If Tera Term has an option to buffer what you type, I'm not aware of it. It's been awhile since I used it.

I'm not a robotics expert either so I appreciate your help BrownOut. I checked the software and I don't see a clear way to modify the buffer. I did notice an option to adjust the transmit delay. I can enter values of "msec/char" and "msec/line". I'll test these out tomorrow when I have the device. This still doesn't seem to be the best option. I'd rather it just wait for me to hit enter and then send it immediately.

Do you know of another free and simple serial terminal app I could try?

Hyperterm, but I'm sure you'll have the same problem. The trick is going to be to program the UART in your target system to buffer the packet. I did some UART programming, but that was years ago. As I remember, my program was interrupt driven, and checked the packet length before forwarding. Aside from that, I don't know a way to do it.

I don't think you can use a terminal program. The following is from the link you provided:

An easy-to-use Windows™ software package
called "ModCom" is available and can be
downloaded from Weeder Technologies' web
site. This program will allow the user to quickly
set up custom buttons which transmit
commands, custom windows that poll for data,
and a variety of other screen objects such as
slider controls, event counters & timers,
bar-graph level indicators, button selection
arrays, and more. In addition, conditional
statements can be set up to take action when
specific events or conditions are met, sequences
can be written and then called by other screen
objects during run-time, and data can be logged
to a file automatically at user-defined intervals.

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