Reading out HART variables from the AI8x16bit HART module (6ES7 331-7TF01-0AB0)

UPD:

When I check a diagnostic buffer of the AI HART module in online I see there 2 messages:

1. "ADC/DAC error. Event ID: 16#F553:8044"

2. "Module without parameters. Event ID: 16#F553:8006"

Time stamps are absent for both messages.

The first one I guess comes because that I haven't any signal 4-20 mA connected to my module.

But the second message about parameters confuses me a little. I think I make all setting via module properties in HW Config in Step7.  Or I need to set module parameters with SFC58 in my program?

P.S. SF led on module is off.

Hi, 

See the SIMATIC ET 200M distributed I/O device HART analog modules manual under chapter "7.1 Overview of the data record interface and user data of the HART communication" and "7.2 Data record interface".

If you need any help with using the SFC's/SFB's, let us known.

Hi!

Thanks for reply!

I want to know exactly do I need to use SFC for configuration HART module or it is enougth to configurate it in HW Config. Also if I setup several Hart variables can I read it with load/transfer mechanism or I also need to use SFC. I haven't real hart sensors yet so I can't check it out.

Maybe somebody could tell about it from his experience.

Hi,

Generally speaking. HART is a communication option to use on the 4-20mA loop for communicating (configuring and diagnosing) to field devices. You normally do not have to use HART protocol to read your Process Value.

See the SIMATIC ET 200M distributed I/O device HART analog modules under chapter "6.1 HART analog input module SM 331; AI 8 x 0/4...20mA HART (6ES7331-7TF01-0AB0)". It says:

"Any measuring range selection per channel
– 0 ... 20 mA / ±20 mA (without HART usage)
– 4 ... 20 mA (with/without HART)"

To be 100% sure check the Field Instrument's manual and loop drawing of the 4-20mA loop.

To get a bit more background information see:

APPLICATION GUIDE

Thank you very much for good applucation guide, I've never seen it before. And for your information.

Yes, I know that primary value (current flowrate) from sensor I can receive via 4-20mA signal. And additional information (media temperature, pressure etc.) I receive via HART protocol (SV, TV variables). But  the user manual is not quite clear about that should I use sfc or not. They describe both ways (sfc and settings in hw config) and don't say what I must do exactly and what I must not.

Maybe somebody on this forum, who solve the same problem in real could explaine it for me.

Hello aag_03,

You don't need SFCs/SFBs to read HART secondary variables.

All you have to do is to access the input double words as you already did.

"

L PID 272    //Var1 value in REAL

Off topic: I recommend to use process image addressing instead of peripheral addressing (e.g. ID 272 instead of PID272).

Just wait until you connect the flow meters to make a real test. Just make sure to configure secondary variables in your flow meters.

Best regards,

H-H

Hello!

Dear H-H! Thank you very much for your brilliant and clear answer. This is really helpful for me now!!!