Mike_O

Controlling heater element with PWM

5 posts in this topic

Hello,

     I want to make an application to control a heater element . I have a thermocouple(k) , I read value from it with ad04u module and with od212 module I want to control the heater element with PWM. Now that's my problem , I don't know how to configure in cx-programmer to put on output from od212 pwm signal. I read in documentation about Pwm but is a poor explication about this problem. (I use CJ2M processor).

What else conditions must to check for I can work with pwm signal?

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PWM can only be used for outputs of MD211/212 Pulse I/O module. Not possible with OD212.

You say "I read in documentation about Pwm but is a poor explication about this problem."

What documentation are you using? It is very clearly explained in the Instruction Reference Manual W474 and Pulse I/O manual W486.

Do you have these?

Here are links:- https://assets.omron.eu/downloads/manual/en/v3/w486_cj2m-md21_pulse_i_o_module_users_manual_en.pdf

https://assets.omron.eu/downloads/manual/en/v3/w474_cs_cj2_nsj-series_plc,_sysmac_one_nsj_series_reference_manual_en.pdf

 

 

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Posted (edited)

That code only addresses PWM Output 0 at 200Hz with a 50% or 25% duty cycle.

Physical output is 2961.4 = Output 4 on the right hand MD211 [Closest to PLC].

"I don't see anything! Or where I can see this pwm signal? "

THIS WILL NOT WORK IF YOU ARE USING SIMULATION MODE IN CX PROGRAMMER OR IF YOU ARE USING 2961.4 AS AN OUTPUT ANYWHERE IN YOUR PROGRAM.

You must have physical PLC and MD211 with downloaded program to "SEE SOMETHING"!

Edited by BITS N BYTES

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You could probably make your own. I would be surprised if you had a thermal mass to heat energy ratio that required heat cycles as fast as 200Hz. Have a cycling timer of a few seconds or whatever timebase works for you. Multiply 0-100 heat PID output by units that make 100% the full cycle time. If this value is less than timer accrued value, energize output. You should have a SSR or similar firing the heater. Mechanical contacts would burn up quickly.

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