Serial Port Commands and Monitoring

[johnk1ese]

I am trying to write a program to poll a commercial inverter once every two seconds.

The inverter manual says -

● RS232 communication port controls with non-synchronous serial transmission (ASCII cord) method.

● RS232 communication program is real time operation, and status can be monitored through serial function of PC screen by program

connected with and provided by computer (PC) application port.
● When using RS232 communication programs other than ones provided by our company, data in each mode can be verified using following

command through PC connection.

Input voltage indication command: BAT?

Output voltage indication command: VOL?

Frequency indication command: FRQ?

Output current indication command: AMP?

When entering commands in the command window, even question marks should be typed accurately, and make sure to use upper case as it

distinguishes upper and lower cases.

I wrote this code -

[setup.main.Window]



   '-----Begin code for #main

   nomainwin

   WindowWidth = 250

   WindowHeight = 200

   UpperLeftX=100

   UpperLeftY=100

   BackgroundColor$ = "Yellow"

   ForegroundColor$ = "black"



   '-----Begin GUI objects code



   statictext #main.dc,"DC Input", 5,  5,  100,  25

   statictext #main.ac,"AC Output", 5, 35,  100,  25

   statictext #main.fr, "Frequency", 5, 65, 100, 25

   statictext #main.am, "AMP", 5, 95, 100, 25

   statictext #main.dcshow, "DC", 120, 5, 90, 25

   statictext #main.acshow, "AC", 120, 35, 90, 25

   statictext #main.frqshow, "Freq", 120, 65, 90, 25

   statictext #main.ampshow, "Amp", 120, 95, 90, 25

   button #main.buttonstart, "Start", [startClick], UL, 5, 130, 100, 25

   button #main.buttonstop, "Stop", [stopClick], UL, 120, 130, 100, 25

   '-----End GUI objects code



   open "C:\AIMS\AIMS Monitor.ini" for window as #main

   print #main, "font ms_sans_serif 14"

#main "trapclose [close]"



   Com = 16384

[configure]



oncomerror [badport]

   inverterport$ = "com3:2400,n,8,1"



   wait



[startClick]

   timer 2000, [reading]


[reading]

 open inverterport$ for random as #aims  

       buffer$ = ""

       dataRead$ = ""

       print #aims, "BAT?"

       while len(buffer$) < 4

           dataRead$=input$(#aims, 1)

           buffer$=buffer$+dataRead$

           scan

       wend

       print #main.dcshow, Left$(buffer$,4)

       dataRead$ = ""

       close #aims


 open inverterport$ for random as #aims          

       buffer$ = ""

       dataRead$ = ""

   print #aims, "VOL?"

           while len(buffer$) < 4

           dataRead$=input$(#aims, 1)

           buffer$=buffer$+dataRead$

           scan

       wend

       print #main.acshow, Left$(buffer$,4)

       buffer$ = ""

       close #aims


 open inverterport$ for random as #aims          

       buffer$ = ""

       dataRead$ = ""

   print #aims, "FRQ?"

       while len(buffer$) < 4

           dataRead$=input$(#aims, 1)

           buffer$=buffer$+dataRead$

           scan

       wend

       print #main.frqshow, Left$(buffer$,4)

       buffer$ = ""

       close #aims


 open inverterport$ for random as #aims          

       buffer$ = ""

       dataRead$ = ""

   print #aims, "AMP?"

       while len(buffer$) < 4

           dataRead$=input$(#aims, 1)

           buffer$=buffer$+dataRead$

           scan

       wend

       print #main.ampshow, Left$(buffer$,4)

       buffer$ = ""

 close #aims

wait



[stopClick]

goto [close]





[badport]

   notice, "Serial Port Error"

   notice, "Error: "; ComError$

   notice, "Port number: "; ComPortNumber

   notice, "Error code: ";ComErrorNumber

   close #aims





[close]

close #main

end


I had tried it without opening and closing the port each time but it would get extra characters left over from the prior message instead of just the message response from the new command.  I couldn't flush the buffer each time and closing the port was the only thing that worked.

However, with the code above it works a few cycles before there is a serial port error and the program crashes.  I don't know what to try next

John K1ESE

[Rod]

Away from my pc. Your open command should have the additional handshaking commands. No need to open and close you just need to understand what the response message is and how it is terminated. Also you don’t use the ; character when sending your query but that may not matter.

There is an article you should read on the LBPE under communications.

Also is there a web support page for the device?

[johnk1ese]

Hi Rod -

I'll add the DS0 as a com option. Others? I'll add the ; character at the end of each command.

My code experiments often lock up the serial port in the inverter. Since the inverter is remote and I am using VNC to access the computer at the site, I have to wait for someone to physically restart the inverter. Perhaps adding DS0 will help that.

There is no web support page. I will call the company Monday to try and find the length and terminating character of the return message.

What's LBPE?

73,
John K1ESE

[Brandon Parker]

Which AIMS model is it, and is there an online manual for it?


{:0)

Brandon Parker

[Brandon Parker]

Nevermind, I found the manual I believe.

Your COM Port connection string appears to be incorrect. You have the Stop Bits set to 1, but the manual indicates that the Stop Bits should be set to 0.

inverterport$ = "com3:2400,n,8,0"

I have quite a bit of commercial inverter experience, 1.5 MW inverters ... they are awesome ...

If you need more help just let me know.  I would definitely be willing to chat live as well.

{:0)

Brandon Parker

[johnk1ese]

Brandon -

I saw that but saw the LB help said the only stop bit choices were 1 and 2. I will try if after the fellow shows up at the remote site and reboots the inverter.

Once that is done I will try it and let you know the result. I will likely need additional help.

The situation is that a solar panel charges batteries which provide about 24 DC volts. The inverter is rack-mounted and outputs the 117 AC voltage. We haven't yet hooked anything up to the inverter output. Eventually, it will power a ham radio transceiver on a mountaintop in Maine.

73,
John K1ESE

[Rod]

Brandon will get you sorted, teamwork! 😀

[Brandon Parker]

Aug 23, 2020 14:51:36 GMT -5 johnk1ese said:

Brandon -

I saw that but saw the LB help said the only stop bit choices were 1 and 2. I will try if after the fellow shows up at the remote site and reboots the inverter.

Once that is done I will try it and let you know the result. I will likely need additional help.

The situation is that a solar panel charges batteries which provide about 24 DC volts. The inverter is rack-mounted and outputs the 117 AC voltage. We haven't yet hooked anything up to the inverter output. Eventually, it will power a ham radio transceiver on a mountaintop in Maine.

73,
John K1ESE

Yeah, normally you will see most things take 1 stop bit.  This is typically how Serial transmitters/receivers determine the end of a 

It is unclear whether the Windows API will actually accept 0 stop bits or if it is just talking about the .NET and/or C# property fields. I only say 0 because that is what the manual showed with their software, but who knows if that was actual software running or if they just pasted an image and values over it.

Rereading your post I see that it works with your current code so just stick with the 1 stop bit for now. How long does it take to fail once you start reading data?

Here is what I typically use for the COM port string to communicate with UART devices. Note that I set the COMPort & BaudRate variables to your values.
COMPort = 3
BaudRate = 2400
inverterport$ = "Com";COMPort;":";BaudRate;",n,8,1,ds0,cs0,rs0"

Do you have Discord? Maybe we can set up a time to discuss and possibly screen share when someone is at the site?


{:0)

Brandon Parker

[johnk1ese]

Brandon -

I've been out of town. Let me see what's up tomorrow and I will get back to you.

We did find there was a duplicate port in the remote setup. That has been resolved and perhaps it will solve the problem. I doubt I will be that lucky and may take you up on your offer.

Thanks!
John
K1ESE

[Brandon Parker]

No worries ...

{:0)

Brandon Parker