LR460 radar level measurment

Hello,
I´m trying to connect to hart loop with sensor siemens sitrans LR460 level transmitter(4-20mA,hart compatible) using hart communicator 375 emerson.
I wire hart with sensor exactly like on screen in attachment with one change that i always disconnect wires from analog input card in local control box and then i connect them with hart throught resistor on negative wire , these LR460 sensors are all active and have own powered mA loop so i don´t need source of power .
Hart is still unable to find sensor device , i don´t know where problem could be.
When i do DC voltage measurmet test on hart it shows around 23V , which is strange as long as i used resistor in loop .

I also changed in Poll address range from 0 to 0-63 , didn´t also help.
Last thing i tried was downloading EDD´S from siemens for this LR460 sensor i copied them on memory card , but they were here all the time because when i have been copying files to memory card it asked me to replace same named files.

The sensor is difficult to access , it is in dangerous height , so i have only option to connect on it´s wires from local control box ,taking them off the analog input card.

Any help would be appreciated .

Thanks

 

Attachments

1. Wiring
The HART communicator should not be part of the loop or 'inside' the current loop. The HART communicator wants to see the voltage drop across the loop resistance; the communicator is not designed to pass loop current (I hope it hasn't been damaged by your trying to drive loop current through it).

The communicator's black probe leads should be connected across the loop's load resistor.

Two ways to do that.

A. Reconnect the wiring as it was originally found. The analog input probably has 250 Ohms of resistance because every current AI has a 'shunt' resistor to convert current to voltage.

Connect the probe leads across AI terminals 8 and 7. Or if they're accessible, connect HART probe leads to terminals 1 and 2 in the junction box. Polarity does not matter for HART, either lead can connect to either terminal.

HART communicator connected, wiring as is.JPG

B. If you insist on disconnecting the LR460 from the analog input then install the 250 Ohm resistor between the open wires running to the LR400 which will complete the loop so loop current flows.

Then connect the probe leads across the 250 Ohm resistor.

HART communicator connected, wiring disconnected from AI.JPG

2. HART address
Every HART device comes from the factory with HART address 0, because 99.8462% of all HART devices are used point-to-point, connected directly to an analog input, like your situation. The industry expectation is that point-to-point connections will use HART address 0. HART addresses other then 0 should only be used for the quite rare HART multidrop situations where unique device HART addressing is required.

So configure the LR400 for HART address for 0 and leave it there. Make sure the HART communicator is set up so it is addressing HART address 0.

3. DD driver file

The 475 replaced the 375. The 475 was around for quite awhile.
I don't know if the LR460 DD file will work in a 375.

A generic HART function, like tag name, should work, but radar really needs specific functions like mode (distance or level) and very specific settings to determine the measuring range, which require a DD. So I'm just not sure whether a 375 will handle an LR400, depending on how it handles the LR460 DD file.

If I recall properly, plain old worker bees, like me, couldn't even update the 375 DD files, I think it had to be done by a 'manufacturer' who had the privelege of buying whatever licensing and equipment was needed to updating DD files (definitely the case with 275, and I think it was so with the 375, but someone can correct me on this).

Please let us know if you are successful in getting an LR400 DD into the 375 and if you can satisfactorily configure the LR400 with the 375.
 
1. Wiring
The HART communicator should not be part of the loop or 'inside' the current loop. The HART communicator wants to see the voltage drop across the loop resistance; the communicator is not designed to pass loop current (I hope it hasn't been damaged by your trying to drive loop current through it).

The communicator's black probe leads should be connected across the loop's load resistor.

Two ways to do that.

A. Reconnect the wiring as it was originally found. The analog input probably has 250 Ohms of resistance because every current AI has a 'shunt' resistor to convert current to voltage.

Connect the probe leads across AI terminals 8 and 7. Or if they're accessible, connect HART probe leads to terminals 1 and 2 in the junction box. Polarity does not matter for HART, either lead can connect to either terminal.

View attachment 1604

B. If you insist on disconnecting the LR400 from the analog input then install the 250 Ohm resistor between the open wires running to the LR400 which will complete the loop so loop current flows.

Then connect the probe leads across the 250 Ohm resistor.

View attachment 1606

2. HART address
Every HART device comes from the factory with HART address 0, because 99.8462% of all HART devices are used point-to-point, connected directly to an analog input, like your situation. The industry expectation is that point-to-point connections will use HART address 0. HART addresses other then 0 should only be used for the quite rare HART multidrop situations where unique device HART addressing is required.

So configure the LR400 for HART address for 0 and leave it there. Make sure the HART communicator is set up so it is addressing HART address 0.

3. DD driver file

The 475 replaced the 375. The 475 was around for quite awhile.
I don't know if the LR400 DD file will work in a 375.

A generic HART function, like tag name, should work, but radar really needs specific functions like mode (distance or level) and very specific settings to determine the measuring range, which require a DD. So I'm just not sure whether a 375 will handle an LR400, depending on how it handles the LR400 DD file.

If I recall properly, plain old worker bees, like me, couldn't even update the 375 DD files, I think it had to be done by a 'manufacturer' who had the privelege of buying whatever licensing and equipment was needed to updating DD files (definitely the case with 275, and I think it was so with the 375, but someone can correct me on this).

Please let us know if you are successful in getting an LR400 DD into the 375 and if you can satisfactorily configure the LR400 with the 375.
Thank you for answers
As long as there is no junction box betwen sensor and control box , i can close loop only like this am i right ?

1632158515533.png
 
You seems to not be confortable with such devices and how to test /calibrate them...either troubleshoot them...

The screenshots that i shared are clearly expalining how to connect such devices..
 
I think i have tried it also with letting it inside analog input card with connecting through wago clamps adding sensor wires to each wago clamps , and from each wago calmps one additional wire back to analog input card terminals , and one more wire in wago clamps for connecting hart probes .
 
My mistake, I thought the LR460 was the device at the top, but it isn't, that's the AI.

You are correct in connecting the HART communicator as shown in your graphic in post #5.
 
My mistake, I thought the LR400 was the device at the top, but it isn't, that's the AI.

You are correct in connecting the HART communicator as shown in your graphic in post #5.
Just to be sure as long as i use hart first time , just because sensor is difficult to acess , do you also count with that sensor is already powered loop ?
I wrote it , just to be sure because i saw lot of connections in some examples but none of them worked and this one i haven´t tried.
 
Hello,
It Works, problém i had before was that on analog input card wass missing wire which connects M-Ground to AUX contact on card so my loop wasnt closed all the time i did it with using resistor of analog input card.
Thanks
 
Hello,
It Works, problém i had before was that on analog input card wass missing wire which connects M-Ground to AUX contact on card so my loop wasnt closed all the time i did it with using resistor of analog input card.
Thanks
Hello.

Good to hear back from you.. And that it works!

Any time
Controls Guy25
 
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