TheBackShed.com

Forum Index : Microcontroller and PC projects : Grey Cells need checking

Author

Message

OA47

Guru

Joined: 11/04/2012
Location: Australia
Posts: 986

Posted: 10:47pm 31 Jan 2019

Copy link to clipboard

Print this post

I have a sub routine that is not working as expected and I was wondering if someone could point out my error.

I have a star network of LoRa units attached to a MM and the controlling radio broadcasts a time stamp regularly to keep the remote unit clocks up to date for reporting purposes. The time stamp is 10 characters in length and is made up of DDMMYYHHMM. The remote units react to any string ending in a CR but occasionally I will get a unit that reboots and as the console port is connected to the radio RS232 it broadcasts the reboot characters. This should not be a problem except the other units are rebooting in sympathy as they are seeing some of this code as an incorrect date format and rebooting on Error: Invalid date (the string sent out is "__________" and the code is trying to set the date as "__/__/__". I thought that my code would exclude this sort of string.

Sub SetClock
' N$ Should look like "2512191645"
If Val(Mid$(N$,5,2)) > 18 Then If Val(Right$(N$,4)) < 2400 Then
D$=Left$(N$,2)+"/"+Mid$(N$,3,2)+"/"+Mid$(N$,5,2)
Print " Date$ set to "; D$
Date$=D$
T$=Mid$(N$,7,2)+":"+Right$(N$,2)+":30"
Print " Time$ set to "; T$
Time$=T$
Else
Print Err$(5)
End If
End Sub

Help

OA47

disco4now

Guru

Joined: 18/12/2014
Location: Australia
Posts: 1003

Posted: 11:09pm 31 Jan 2019

Copy link to clipboard

Print this post

I am not sure this is a valid structure for the IF THEN on a single line.

If Val(Mid$(N$,5,2)) > 18 Then If Val(Right$(N$,4)) < 2400 Then
....

What about

If Val(Mid$(N$,5,2)) > 18 AND Val(Right$(N$,4)) < 2400 Then
...

An initial test that its length is 10 would also help filter out non dates

If (len(N$)=10) AND (Val(Mid$(N$,5,2)) > 18) AND (Val(Right$(N$,4)) < 2400) Then
...

Latest F4 Latest H7 FotS

OA47

Guru

Joined: 11/04/2012
Location: Australia
Posts: 986

Posted: 11:31pm 31 Jan 2019

Copy link to clipboard

Print this post

Thanks disco4now,

Quote An initial test that its length is 10 would also help filter out non dates

The string is tested to be 10 chars long before it proceeds to the sub.

Changed the code from a "Then If " to an "And" and I haven't got the Invalid date error but I also haven't seen the Err$(5) printed.

OA47

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 12:01am 01 Feb 2019

Copy link to clipboard

Print this post

Quote N$ = "2512191645"

setclock
n$ = "__________"

setclock

SUB SetClock
' N$ Should look like "2512191645"
IF VAL(MID$(N$,5,2)) > 18 THEN
IF VAL(RIGHT$(N$,4)) < 2400 THEN
D$=LEFT$(N$,2)+"/"+MID$(N$,3,2)+"/"+MID$(N$,5,2)
PRINT " Date$ set to "; D$
DATE$=D$
T$=MID$(N$,7,2)+":"+RIGHT$(N$,2)+":30"
PRINT " Time$ set to "; T$
TIME$=T$
ENDIF
ELSE
PRINT Err$(5)
END IF
END SUB

Combining single line and multiline IFs is not a good idea

Date$ set to 25/12/19
Time$ set to 16:45:30
[20] Print Err$(5)
Error: ERR is not declared
>

Jim

VK7JH
MMedit

OA47

Guru

Joined: 11/04/2012
Location: Australia
Posts: 986

Posted: 12:24am 01 Feb 2019

Copy link to clipboard

Print this post

Thanks Jim. I thought I might give the string another qualifier as well and see how that goes.

Sub SetClock
' N$ Should look like "2512191645"
If Val(Mid$(N$,3,2)) < 13 Then
If Val(Mid$(N$,5,2)) > 18 Then
If Val(Right$(N$,4)) < 2400 Then
D$=Left$(N$,2)+"/"+Mid$(N$,3,2)+"/"+Mid$(N$,5,2)
Print " Date$ set to "; D$
Date$=D$
T$=Mid$(N$,7,2)+":"+Right$(N$,2)+":30"
Print " Time$ set to "; T$
Time$=T$
End If
End If
Else
Print Err$(5)
End If
End Sub

OA47

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 12:35am 01 Feb 2019

Copy link to clipboard

Print this post

In that case you can combine

If Val(Mid$(N$,5,2)) > 18 Then
If Val(Right$(N$,4)) < 2400 Then

into

If Val(Mid$(N$,5,2)) > 18 and Val(Right$(N$,4)) < 2400 Then

Jim

VK7JH
MMedit

WhiteWizzard
Guru

Joined: 05/04/2013
Location: United Kingdom
Posts: 2944

Posted: 10:30am 01 Feb 2019

Copy link to clipboard

Print this post

TassyJim said

If Val(Mid$(N$,5,2)) > 18 and Val(Right$(N$,4)) < 2400 Then

I strongly recommend putting brackets around the expressions either side of the AND to ensure the 'correct parts' are AND'd:

If (Val(Mid$(N$,5,2)) > 18) AND (Val(Right$(N$,4)) < 2400) Then

Also makes it clearer to read when tracking down errors

Edited by WhiteWizzard 2019-02-02

CaptainBoing

Guru

Joined: 07/09/2016
Location: United Kingdom
Posts: 2170

Posted: 11:08am 01 Feb 2019

Copy link to clipboard

Print this post

as an aside (a bit) here, I have two functions that use regular expressions to validate the "look and feel" of date and time strings and then the actual values of them here:

http://www.fruitoftheshed.com/MMBasic.IsDate-and-IsTime-functions-VB-Work-A-Like.ashx

the functions simply return a true(1) or false(0) if the input string is or isn't a date or time.

I use this all over my code where I set the date & time remotely - One product I have uses a star network of HC-12s and slave nodes get a periodic broadcast timecheck just like yours. The slaves pick out the time and date then use these two functions before setting their own internal clocks to prevent errors from garbage.Edited by CaptainBoing 2019-02-02

Print this page

To reply to this topic, you need to log in.