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maharadza

modbus RS-485 with JAZZ

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I need to establish communication betwwen jazz (master) and energy analyzer-klea as slave using RS-485.

Model of jazz is JZ10-11-UA24 with MJ20-RS.

I need to read float value in klea starting addres 0 (Average voltage of three phases)

I am newbie with unitronics and modbus ...

Tnx in advance for any help.

 

In attached files are:

1-klea modbus function

2-data adress in klea

3-example in klea

post-45946-0-82011600-1448448004_thumb.jpg

post-45946-0-97887900-1448448021_thumb.jpg

post-45946-0-90755200-1448448029_thumb.jpg

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Hi maharadza,

MODBUS reads 16 bit registers/tags.

Even if you successfully read 2x16 bit tags in squential MIs, Jazz PLC does not support float point numbers and cannot process it.

It is recommended to use other PLC, which have support of Floating Point numbers.

For example, SAMBA PLC.

 

Please post klea documentation, or link to manufacturer site.

Example you posted have unbelievable for 32 bits Float Point numbers (IEEE 754) high precision of 10 digits.

In accordance to IEEE 754, Single Precision 32 bit Float Point numbers have precision of 7.22 decimal digits.

After mathematical operations precision will be 5-6 decimal digits.

 

What you will do with received Float Point number? Only show on display?

 

B.R.

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Hi maharadza,

MODBUS reads 16 bit registers/tags.

Even if you successfully read 2x16 bit tags in squential MIs, Jazz PLC does not support float point numbers and cannot process it.

It is recommended to use other PLC, which have support of Floating Point numbers.

For example, SAMBA PLC.

 

Please post klea documentation, or link to manufacturer site.

Example you posted have unbelievable for 32 bits Float Point numbers (IEEE 754) high precision of 10 digits.

In accordance to IEEE 754, Single Precision 32 bit Float Point numbers have precision of 7.22 decimal digits.

After mathematical operations precision will be 5-6 decimal digits.

 

What you will do with received Float Point number? Only show on display?

 

B.R.

Hi tnx for fast response.

This is link for klea (klemsan) device.

http://www.klemsan.com.tr/SF/1572/Klea_ENG_27112013.pdf

I need to read PF (power factor) at address 12 for regulation excitacion current of synchronous generator. (Adress 12)

Can I convert float to intergers? Low precision will work also ...

I set ID of klea device to 1 and baud rate 19200.

Can you give me some example for modbus communication that will suit my example ...

I found one example on forum and modified it, but dont works.

MI 10,MI 11,MI 12,MI13 dont receive values from (address 0 in klea device) when press 1 on PLC...

I do something wrong here.

Example is attached

example.U90

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According to the klea documentation, all Modbus data available is floating point.

 

A Jazz won't work. At all.  You can't convert floating point to something else if you don't have anywhere to put the floating point in the first place.

 

You'll have to trade up to a Vision series.

 

Joe T.

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Well I got 2 integers 16bit

Example I read voltage on klea 117.3 V

Jazz reads

1st integer:17130

2nd integer:-23276

 

1st integer convert to binary is 0100001011101010

2nd integer covert to binary is 1010010100010100

 

When put togather that is 32bit number

01000010111010101010010100010100

 

First bit is sign,then eight exponent bits and 23 mantisa bits

 

Formula for calculate is here

http://sandbox.mc.edu/~bennet/cs110/flt/ftod.html

and for example above I get 117.32242

 

Now I have to put this formula in ladder ... and it will be dificult ... hope will get solution

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You've made contact, which is good.

 

You've done the research to convert the number, which show you understand the data.

 

Now all you have to do is understand that you're not using the right controller with a Jazz.  If you read the data with a V130 the floating point read is a standard Modbus function block.

 

Joe T.

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