High-level + endian possible? | which way has lowest system load?

[gutschein]

I've 2 questions:

• I'd prefer the high-level API for my system, but I need another endian (BIG_ENDIAN_LOW_WORD_FIRST)). Is ist possible to change endian directly for each address. Maybe something like this from your example
  ->int16(657, 'battery3_voltage_wo','BIG_ENDIAN_LOW_WORD_FIRST')
  or is it a must to use the low-level solution for another endian?

• If I'd like to read e.g. 20 addresses ~ 15sec. Which is the best way from the perspective of system load?

[aldas]

1. Currently no (i'll add todo issue for that). But you can use callback to achieve similar result

    ->int16(657, 'battery3_voltage_wo', function ($result, $readRegisterAddress, $response) {
        return $response->getWordAt(657)->getInt16(\ModbusTcpClient\Utils\Endian::BIG_ENDIAN_LOW_WORD_FIRST)
    })

callback is called after value is extracted and it has access to response so you can overwrite value with new value.

2. for If I'd like to read e.g. 20 addresses ~ 15sec. Which is the best way from the perspective of system load?

From request point of view couple of requests (I assume those 20 addresses are not that wide apart that many requests are split) does not create much load.
I have a example for CLI poller that you could modify to fire every 15 sec and do request + store results to somewhere
https://github.com/aldas/modbus-tcp-client/blob/master/examples/example_cli_poller.php

[gutschein]

Thank you Martti.
to 2. sounds good - I will try.
to 1.)... maybe I'm just not as good with that code stuff as I'd like to. I get errors. Maybe as my addresses are all int32, uint32, uint64? I Tried ->getUInt32, but it doesn't work. The library contains maybe getInt16 and getUInt16 only by now?
And what is the meaning of the value 657 in getWordArt(657)? It seems to be a length or offset; but how do I derive the proper value?

  ->uint32(30845,'battery status',function ($result, $readRegisterAddress, $response) {
        return $response->getWordAt(657)->getUInt32(\ModbusTcpClient\Utils\Endian::BIG_ENDIAN_LOW_WORD_FIRST);
    })

PHP Fatal error: Uncaught ModbusTcpClient\Exception\InvalidArgumentException: offset out of bounds in /usr/local/edomi/main/include/php/modbus-tcp-client/vendor/aldas/modbus-tcp-client/src/Packet/ModbusFunction/ReadHoldingRegistersResponse.php:152

[aldas]

sorry, I did not try it out. $readRegisterAddress has field address and you can you this for extraction

 ->uint32(30845,'battery status',function ($result, $readRegisterAddress, $response) {
        return $response->getWordAt($readRegisterAddress->address)->getUInt32(\ModbusTcpClient\Utils\Endian::BIG_ENDIAN_LOW_WORD_FIRST);
    })

NB: this is on top of my head. I did not try it out :)

[gutschein]

seems to work...Address is accessable... :)
next issue:
PHP Fatal error: Uncaught Error: Call to undefined method ModbusTcpClient\Packet\Word::getUInt32() in /usr/local/edomi/main/include/php/modbus-tcp-client/test.php:11

[aldas]

You are currently trying to extract uint32 from word/register. 1 register/word is 16 bit. For 32bit values you need to work with double words. So replace getWordAt with getDoubleWordAt

  ->uint32(30845,'battery status', function ($result, $readRegisterAddress, $response) {
        return $response->getDoubleWordAt($readRegisterAddress->getAddress())->getUInt32(\ModbusTcpClient\Utils\Endian::BIG_ENDIAN_LOW_WORD_FIRST);
    })

[aldas]

NB: If all your values are with same endian you could just change global/default endian value

add somewhere at the beggining of your code:

Endian::$defaultEndian = Endian::BIG_ENDIAN_LOW_WORD_FIRST;

[gutschein]

Perfect! You really impress me. Thank you. SOLVED!

            [battery status endian] => 27
            [battery status pure] => 1769472

with

  ->uint32(30845,'battery status endian', function ($result, $readRegisterAddress, $response) {
        return $response->getDoubleWordAt($readRegisterAddress->getAddress())->getUInt32(\ModbusTcpClient\Utils\Endian::BIG_ENDIAN);
    })
  ->uint32(30845,'battery status pure')

I will try to change the default endian, too.

[gutschein]

With a leading
use ModbusTcpClient\Utils\Endian;
the change of the default value works perfect! That make's it much easier and the code much lean. 👍
This info is less for you...more for people like me with the same issues... :)