Problem with Dual Digital Pot DFR0520
mao73a 2019-02-13 23:51:26 3339 Views1 Replies Hi,
I am having a hard time with Dual Digital Pot - DFR0520.
The project goal is to get a temperature settings from Rapsberry (www server), send it to Arduino and then set the proper resistance on DFR0520 plugged to a Viessmann heater weather compenstion input to simulate desired tempreature.
I am using:
- DFR0520 - Dual Digital Pot
-Arduino Uno
-Arduino IDE 1.8.8
-Raspberry PI Zero W connected to Arduino via Level Logic Converter with serial link: TX-RX (Arduino Pins: 0 and 1)
When setting resistance value for DFR0520 without Raspberry Pi Zero W beeing connected, the Pot works fine! The Viessmann heater seems to "see" expected temperature. However when I only plug TX-RX pins to cable with Raspberry on the other side, DFR0520 seems to set wrong resistance values. After that if I pull off TX-RX cables from Arduino/Raspberry everything seems to work fine again.
Could You please give me any clue/suggestions about what I'm doing wrong?
Arduino and Raspberry are connected through the logic level converter. It doesn't matter if both devices are supplyed from the one electricity source or two separate sources - the problem occurs.
I've even thought than the Pot has some defect so I ordered another one but the outcome is the same.
Thanks in advence for any help.
Regards,
Mao
I am having a hard time with Dual Digital Pot - DFR0520.
The project goal is to get a temperature settings from Rapsberry (www server), send it to Arduino and then set the proper resistance on DFR0520 plugged to a Viessmann heater weather compenstion input to simulate desired tempreature.
I am using:
- DFR0520 - Dual Digital Pot
-Arduino Uno
-Arduino IDE 1.8.8
-Raspberry PI Zero W connected to Arduino via Level Logic Converter with serial link: TX-RX (Arduino Pins: 0 and 1)
When setting resistance value for DFR0520 without Raspberry Pi Zero W beeing connected, the Pot works fine! The Viessmann heater seems to "see" expected temperature. However when I only plug TX-RX pins to cable with Raspberry on the other side, DFR0520 seems to set wrong resistance values. After that if I pull off TX-RX cables from Arduino/Raspberry everything seems to work fine again.
Could You please give me any clue/suggestions about what I'm doing wrong?
Arduino and Raspberry are connected through the logic level converter. It doesn't matter if both devices are supplyed from the one electricity source or two separate sources - the problem occurs.
I've even thought than the Pot has some defect so I ordered another one but the outcome is the same.
Thanks in advence for any help.
Regards,
Mao
2019-02-22 18:13:44 For anyone who will encouter this problem in the future...
I have managed to work around the problem by connecting the arduino and the raspberry pi using an optocoupler instead of a logic level converter. The transfer speed dropped from 9600 to 4800 baud but it doesn't matter.
Still no idea what was causing the problem.
Hope this will help someone. mao73a
I have managed to work around the problem by connecting the arduino and the raspberry pi using an optocoupler instead of a logic level converter. The transfer speed dropped from 9600 to 4800 baud but it doesn't matter.
Still no idea what was causing the problem.
Hope this will help someone.
mao73a 