ET200isp - inverted polarity

Hi

I have a client in chemical industry witch usually works with modules from EXCOM (TRCKFF9F.GSD). For this project he wanted evaluate siemens ET200isp modules. We experienced some lack of functionality and I am not sure they will continue use of ET200isp.

With excom modules, we can choose the polarity of inputs as “normal” or “inverted”. I did not find the same parameter in the ET200isp. This functionality is needed because the type of NAMUR sensor used give 0 when he is covered. But we would like to have 1 when covered. (vane_open = 1 / valve_close=1)

Excom also provide a hexadecimal string witch summarize the configuration of modules. It is interesting to check the configuration of all modules and channels without opening all sub categories.

All information about will be appreciated. [:)] Has somebody encountered some similar experiences?

Regards

Rey Cyril

Hi,

It is what I did for this project. I inverted those inputs with W_XORW blocs at the beginning of the main cycle OB1. For this project they agree working like that because it was evaluation of new material and because we currently do no have other possibility. Moreover we would like to change it because it is not clean.

There are two types of sensors: capacitive and inductive. By default, when covered inductive sensors give 1 and capacitive sensors give 0. For capacitive sensor we must choose inverted polarity because we always want have 1 when sensor is covered.

For example if we check the position of a valve, we put a sensor for the close state (GSL) and a sensor for the open state (GSH), depending on what we need. If the valve is close, the GSL must return 1, if the valve is open, the GSH must return 1. That is normalized over the Chemical site we are working for.

By default, with capacitive sensors, the ET200isp give us the opposite (close =notGSL/open=notGSH) and we can no select polarity in Hardware Config?

Thank you Late
Best regards

Rey Cyril
Retel-Collombey SA

I am not a specialist of Namur sensors, but I experience that it is not really 1 or 0. Namur sensors works with a current loop :

We can detect short circuit or broken line with Namur sensors. Then the security is correct. The problem, I think, is the interpretation of “high current” and “low current”.

When covered inductive sensors return high current and capacitive sensors return low current. In my own I can considered inductive as a normally open switch and inductive as a normally close switch. But in fact, until now, my client gets used to have 1 when covered...

More than this, I ask somebody about the state of the small led signal on the sensor. He tells me that it is inverted too by inverted configuration. That let me perplexed !?