Cell constant was calculated as 760/cm (while the maximum for the dev board is 100/cm). EXC voltage is 1.2
Baud rate: 115200 bps
So on the J2 header, pin 1 and 3 are always high.
2-electrode sensor is connected, and conductivity measurements are around 11.65 uS/cm
I am trying to replicate what you're getting on the RS-485 signals. Are you trying to command the board through RS-485?
Also, the rms voltage of the conductivity sensor output is 1.21V which is pretty close to the EXC voltage. The conductivity reading you got, 11.65 uS/cm, with a cell constant of 760 /cm is equivalent to 15.33 nS or 65.2 Mohms. Is this consistent with what you're trying to measure?
The RTD is there for temperature compensation of conductivity measurements. The simplest way you can simulate one is using a 100 ohm or 1000 ohm resistor in 2-wire connection at pins 1 and 4 of J3.
I am just trying to see the data of the conductivity sensor through a terminal emulator. I just changed the EXC voltage to 1 V, and still nothing. EXC frequency is 10 Hz, setup time is 10%, hold time is 1%.
I was handed this project, so I'll ask what impedance it should be measuring...
Thank you! Interesting to know how to simulate an RTD. I put a 1k in, and the error persists.
To view the data of the conductivity sensor through RS485, you will have first to issue a command also via RS485. In your case, the command is "7 poll". The command should end with the LF character and should have no extra spaces.
Note that the board accepts only half-duplex RS485 connections as a client or slave.
For more information on the syntax and other commands, check the software wiki user guide: https://wiki.analog.com/resources/eval/user-guides/circuits-from-the-lab/cn0359
If using PuTTY, is there a certain setting to go into to send that?Under Session, I configured the COM port and baud rate (115200). Under Serial, I did the same.
The terminal emulator opens, but I cannot send commands to the device. That's why I think I'm missing something in PuTTY's settings.
Is this the same setting in the CN0359?
How are you connecting the CN0359 to the PC? PuTTY commands a serial port from the PC which would need to be translated to RS485 voltages. Also, CN0359 supports only half-duplex RS485 so your transceiver or translator also has to be able to support this.
Yes. The CN0359 is set to 115200 baud.
I'm using a StarTech RS422 Rs485 USB to serial cable adapter with COM retention:
I see no problem with the translation to RS485 signals using this adapter. Can you set PuTTY in the Terminal category, with "Local echo" and "Local line editing" in Force on. Also, check the "Implicit CR in every LF" and "Implicit LF in every CR"
Another thing that may have happened is miss-wiring the RS485 connection to the CN0359. Here is a picture of the correct setup.
I changed the settings for those four perimeters in PuTTY. I typed
"poll 7" (enter), "7 poll" (enter), "poll 7\n" (enter), "7 poll\n" (enter).
Nothing occurred after.
I changed the wiring of A and B for every trial above too.