STOD/DTOS confusion. Studio 5000.

So what I thought would be simple has turned out not to be, or at least it hasn't become obvious enough to me yet.

I have a DINT coming into a CL5380 from an RFID reader. That DINT is in an array with a length of 10. DataRead[10]. There is also a DINT to write the data to the RFID tag if needed for initial setup, DataWrite[10]. So I wanted to set something up so that the end user can enter a STRING tag on the HMI for the data that they wanted written to the RFID tag, seemed like the STOD instruction would be simple and what I needed to use and it seems as if I may have underestimated what it is I need to do.

I was hoping that I would merely be placing the string data into the STRING tag that was the Source in the STOD and then for the Dest use DataWrite[0] and all would be good. I was incorrect and now that I have sat here and played around with it for a bit all of the methods that I have come up with have confused me even further. To the point where I cannot even get a single letter for example "A" to be written to the tag and then read into the PLC. I will do the write and then the read shows a "0" in the DINT array element that I assumed would read "A", after a DTOS of course. Any advice as to what I need to do to accomplish what it is Im looking to do?

STOD will stop converting when it encounters a non-digit in the string (other than a leading '-'). If you need to be writing an 'A' character to the RFID, it sounds like incoming and outgoing data should be string data, but this is contradicted by reading results into a DINT array. So it is not clear how this reader/interface is supposed to work, specifically is the initial setup being sent supposed to be done with an DINT value or a character string?

Edit: I think STOD also skips leading characters until it hits the first numeric or '-', and then converts until reaching another non-numeric or the end of the string.

Mispeld said:

STOD will stop converting when it encounters a non-digit in the string (other than a leading '-'). If you need to be writing an 'A' character to the RFID, it sounds like incoming and outgoing data should be string data, but this is contradicted by reading results into a DINT array. So it is not clear how this reader/interface is supposed to work, specifically is the initial setup being sent supposed to be done with an DINT value or a character string?

Edit: I think STOD also skips leading characters until it hits the first numeric or '-', and then converts until reaching another non-numeric or the end of the string.

Click to expand...

So the reader/interface brings the data into the PLC in DINT form. P&F has an AOI which makes this almost too simple to setup honestly. The only snag I’m having is like I said above, I would love to go from a STRING to a DINT so that when I need to write data to a tag its simple to implement on the HMI side.

I can always just stick with using DINTs and have the tags assigned a number then make a table in the PLC that fills out so tag 12467 = ThisThing and 12358=ThatThing. Again my preference would be so the end user could just type in ThisThing and ThatThing from the HMI level in order to create that data to be written to a new tag.

Silly question. Is your RFID reader capable of handling alphanumeric data?


If so, the array of DINTS seems a little strange for something with an AOI. AB strings are stored as an array of SINTs (With a LEN), where each SINT is a character. Are your DINTS actually 4 SINTs packed together in one element? If that's the case, you need to be packing all your SINTs into the DINT array, so DataRead[0] or DataWrite[0] is actually the first 4 SINTs of your string and so on.


Can you post any links for the RFID system, app notes or the AOI?

Jeev said:

Silly question. Is your RFID reader capable of handling alphanumeric data?


If so, the array of DINTS seems a little strange for something with an AOI. AB strings are stored as an array of SINTs (With a LEN), where each SINT is a character. Are your DINTS actually 4 SINTs packed together in one element? If that's the case, you need to be packing all your SINTs into the DINT array, so DataRead[0] or DataWrite[0] is actually the first 4 SINTs of your string and so on.


Can you post any links for the RFID system, app notes or the AOI?

Click to expand...

All great questions that I am just not sure of the answers. A call to P&F tech tomorrow am may help my cause a bit but in the meantime here is a link to the AOIs for the specific device.

https://www.pepperl-fuchs.com/usa/en/classid_2474.htm?view=productdetails&prodid=41851#software

If my madman ramblings turn out to be correct, you can create a STRING[40] for UI use, strip the LEN by copying it to a SINT[40] and then just dump the SINT array into the DINT array with a COP. I'll see if I have some time tonight to have a look at what's in the link you posted (If someone else doesn't have the answer already).

I hope this will help, I just created a couple functions that will allow the HMI to show the characters of a DINT read by an RFID reader, and allow them to type text in and convert it to a DINT. In my display, I have all the affected controls configured for VBA Control and look for the Change event to call the functions. In the ThisDisplay module:

Private Sub strMatrlBadge0_Change()

Me.txtMatrlBadge0.Caption = DINTToCHAR(Me.strMatrlBadge0.Value)

End Sub

Where both the strMatrlBadge0 and txtMatrlBadge0 are configured for VBA Control. Then in a separate module:

Public Function DINTToCHAR(ByVal lngBadge As Long) As String

Dim intPos As Integer
Dim strCHAR As String
Dim lngMult(1 To 4) As Long

For intPos = 1 To 4
lngMult(5 - intPos) = 2 ^ ((intPos - 1) * 8)
Next intPos

For intPos = 1 To 4
lngVal = Int(lngBadge / lngMult(intPos))
lngBadge = lngBadge - lngVal * lngMult(intPos)
strCHAR = strCHAR & Chr(lngVal)
Next intPos

DINTToCHAR = strCHAR

End Function

Public Function CHARToDINT(ByVal strBadge As String) As Long

Dim intPos As Integer
Dim lngVal As Long

If Len(strBadge) < 5 Then
For intPos = Len(strBadge) To 1 Step -1
lngVal = lngVal + Asc(Mid(strBadge, intPos, 1)) * 2 ^ ((Len(strBadge) - intPos) * 8)
Next intPos
End If

CHARToDINT = lngVal

End Function

I'm still working on a dialog box to allow the user to enter a string and have it converted back to a DINT, but that shouldn't be much different.