Den. Inst. and Mettler balance not responding to print command from Visa

[eclipsecd]

Hello, I am working to interface a Denver Instrument S-8001 and a Mettler Toledo PB5001 analytical balances into the same .vi. Using the VISA sub-vi I can get both balances to report their mass to the .vi, but only if I have them continuously send data (i.e., comm port and baud, etc. are configured correctly). My difficulty is that the continuous readings are both unecessary and are prone to error, and the .vi will oftern record only a portion (or a zero) at any given sampling event. I can further confirm that using hyperterminal the correct print command for the Denver Instrument balance is 'esc+P', and I think the Mettler command is some variation of 'SI'. However, entering either of these commands (and other variations) into the 'string to write' terminal of the VISA write .vi does not appear to send the required information to the balance for it to respond with the measurment. I have spoken with both Metter and DI tech support, and after spending some time with each of them they were unable to resolve the problem... but suggested that maybe the fine folks at NI might have an idea. Looking forward to your response. Thank you!

[Dennis_Knutson · Accepted solution]

How are you sending the esc character? You can't just type esc. It's hex 1B so you could right click on the string control and select 'Hex Display'. There are other functions such a typecast and Byte Array to string that are helpful when doing non-ASCII.

[Albert.Geven]

another question is: do you get an error when sending or it simply has no effect?

[eclipsecd]

Thank you both so much! Dennis' comment about changing the string input to a hex display was the key. Now both balances are up and working.

[Subhayan]

Can you tell me how u read the data for Denver Instrument? I am using the basic read and write vi for reading but the mass reading always comes to zero? Is there some specific command?

[Subhayan]

Hi,

I am using labview to read and write data from Denver Balance and am using the basic read and write vi from the Labview help. But the mass is always recorded as zero. Although no error messages are shown. Can u please tell me where i am going wrong. I have checked the baud rate etc. in both the vi and instrument. They are okay. But the mass reading is always zero. Can anybody help me out. It's really urgent! 

[Subhayan]

Can u upload ur step by step procedure and vi for DEnver instruments to Labview. I have been trying since Last month but unable to connect it.

[Dennis_Knutson]

Provide the model number, the manual, the exact command you are sending, and the type of cable you are using to connect.

Also, have you tried using a program such as Hyperterminal? If that does not work, did you contact Denver Instruments for help?

[Subhayan]

Model number: P4002D. Denver Instrument : Electronic MAss balance instrument.

My block diagram is Basic Serial Write and Read.vi from Labview Example help file.

In the string to read command i have entered : hex 1B+P

it is reading the number of bytes coming to the serial port but not the exact mass reading in the balance.

so if i put a weight on the balance the return is like bytes read : 26 or 35 or 7 and so on while the reading in the balance is 60 /80/2 gms

The manual i have doesnot provide me the C-command for labview reading. I am new to labview so i may have some basic errors. Please help.

[Subhayan]

Type of cable is RS232 cable.