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Electronics => Beginners => Topic started by: cs.dk on February 11, 2018, 10:10:26 am

Title: Programming options on EEZ H24005 PSU
Post by: cs.dk on February 11, 2018, 10:10:26 am
First of all, I know next to nothing on programming. And I'm not even sure the PSU is capable of this exact output-style.

Is it possible to program the PSU to mimic a lambdasensor?
I have a car with a fault, maybe broken wires, maybe bad fuel/air mix. I can't see the lambdavoltage on the tester, and a multimeter confirms that the lambdasensor is giving a very low voltage (20-40 mV) output. Maybe the sensor is trying to drive a short? However the MOT 4-gas analyzer shows a fine lambdavalue when the car is tested. (High CO and HC value, because the ECU thinks it runs lean, and adjusting up accordingly)

If I could inject a lambdasignal right to the ECU, i should be able to see it on the tester, if the ECU's inputs are not dead. And the car should react to it.

The signal is something like this;

(https://www.picoauto.com/images/uploads/screenshots/_lrg/o2_ziconia.png)
Title: Re: Programming options on EEZ H24005 PSU
Post by: prasimix on February 11, 2018, 11:13:22 am
It looks like a sinewave that is around 1 Hz. That is achievable with LIST SCPI commands. Establish connection via USB or Ethernet and send the following commands one by one:

Code: [Select]
list:coun inf
list:volt 0.50, 0.53, 0.55, 0.58, 0.60, 0.63, 0.65, 0.67, 0.69, 0.70, 0.72, 0.73, 0.74, 0.74, 0.75, 0.75, 0.75, 0.74, 0.74, 0.73, 0.72, 0.70, 0.69, 0.67, 0.65, 0.63, 0.60, 0.58, 0.55, 0.53, 0.50, 0.47, 0.45, 0.42, 0.40, 0.38, 0.35, 0.33, 0.31, 0.30, 0.28, 0.27, 0.26, 0.26, 0.25, 0.25, 0.25, 0.26, 0.26, 0.28, 0.30, 0.31, 0.33, 0.35, 0.38, 0.40, 0.42, 0.45, 0.47
list:curr 0.05
list:dwel 0.0164
trig:sour imm
outp 1
init
*trg

Set current is 50 mA, and "dwell" time is 16.4 ms (i.e. 1 Hz / 61 is  ~16.4 ms) You should get something like this:

(https://i.imgur.com/REWN07Hl.png)

Unfortunately we still don't have a simple way of creating "function generation". Therefore you have to use an external application for doing that. Please find in attachment .ods file (converted to .xls too) that is used to generate list of voltages (column D) with desired amplitude (cell D1) and DC offset (cell D2). Number of points is 61 but with current firmware version it could go up to 256.
If voltage precision is not enough you can do the following: define 10x higher amplitude and DC offset and use voltage divider to set it back to needed level. In that case you have to replace voltage list with the following statement:

Code: [Select]
list:volt 5.00, 5.26, 5.52, 5.77, 6.02, 6.25, 6.47, 6.67, 6.86, 7.02, 7.17, 7.28, 7.38, 7.45, 7.49, 7.50, 7.49, 7.45, 7.38, 7.28, 7.17, 7.02, 6.86, 6.67, 6.47, 6.25, 6.02, 5.77, 5.52, 5.26, 5.00, 4.74, 4.48, 4.23, 3.98, 3.75, 3.53, 3.33, 3.14, 2.98, 2.83, 2.72, 2.62, 2.55, 2.51, 2.50, 2.51, 2.55, 2.62, 2.72, 2.83, 
2.98, 3.14, 3.33, 3.53, 3.75, 3.98, 4.23, 4.48, 4.74

This time you'll get this (and don't forget to apply voltage divider!):

(https://i.imgur.com/JahsLiTl.png)
Title: Re: Programming options on EEZ H24005 PSU
Post by: cs.dk on February 11, 2018, 11:55:07 am
Thanks a million :-+
The voltage precision should be fine, it's not that critical.

I'll have to read this chapter, to see how i transfer the commands to the PSU; http://www.envox.hr/eez/bench-power-supply/psu-scpi-reference-manual/psu-scpi-introduction.html (http://www.envox.hr/eez/bench-power-supply/psu-scpi-reference-manual/psu-scpi-introduction.html)
Title: Re: Programming options on EEZ H24005 PSU
Post by: prasimix on February 11, 2018, 12:07:52 pm
It's a very simple: use any serial comm (for USB) or telnet (for Ethernet) console. Former one could be also so-called "Serial monitor" that is included in Arduino IDE. Later one could be PuTTY or command line "telnet" (depends of your OS). For telnet (i.e. Ethernet connection) you have to select port 5025 and IP address of the PSU (you need to activate Ethernet in EEZ H24005 system settings and restart it). Then simply start telnet session with:

telnet <ip_address> 5025
Title: Re: Programming options on EEZ H24005 PSU
Post by: cs.dk on February 11, 2018, 02:09:30 pm
Great, i'll give that a go :-+

However, Ethernet seems to be dead on my device - No LED indicators, and no IP-adress. Will have to look further at this.