Modicon M172 analog output

[pawel_kowalski_]

Hi All,

I have problem with analog outputs AOL1-AOL4 the outputs AOL3 and AOL4 I configure in program as voltage modulation.
I want using this outputs to control device like valve with input 0-10V. I wrote program I see the output is on working but when I measuring output physically using a multimeter there wasn't be a voltage.

Even I wrote a test program to check all analog outputs and when I measuring every output I saw that on analog output AOL5 the voltage was changing propertly.
Where can ba a problem?
I using Machine Expert - HVAC 1.2.1 and modicon 172 File version 596.10

[Ismet_S]

Hi Pawel,

Please check page 99 of attached Hardware Guide M172P Hardware Guide

Only AO3 and AO4 are “configurable” output, and the remaining are set, by defaultm as low voltage analog output 0..10v.

It could be, that the Bios parameter Cfg_Aox has not been configured properly for those two Analog output.

This can be checked directly under the “Commissioning” Tab from the application when connected to the hardware. And the value read should be “2” for Voltage modulation.

Also, make sure that your load resistance is more than 700Ohm

Hope this helps.

Feel free to back to us if you have any questions.

[Bastian_Schmitz]

If you define AO3 and 4 as voltage output via BIOS Parameter through configuration you have to do a download all.

If you download only Programming the default values for Bios and EEPROM would not be written.

Alternativ you can write AO3 and 4 to 0..10V directly via Commissioning or via Webserver 10.0.0.100*/evoindex.htm

(* replace with IP of controller) 

[SalahZahra]

in program , you have to multiply output value by 100
so, to get 10 VDC , you have to write to assigned output vibrable 1000

and so on