資源簡介
php modbus通訊 示例源碼
代碼片段和文件信息
define(‘READ_HOLDING_REGISTERS‘?0x03);
define(‘READ_INPUT_REGISTERS‘?0x04);
define(‘MBAP_HEADER_SIZE‘?7);?//7bytes
define(‘MODBUS_TCP_MAX_ADU_SIZE‘?260);?//260bytes
define(‘MODBUS_TCP_MIN_RESPONSE_DATA_SIZE‘?2);?//2bytes
define(‘MODBUS_TCP_UNPACK_FUNC_BYTECOUNT‘?‘Cfunc/Cbyte_count‘);
//check?MODBUS?TCP?MBAP?header
function?check_mbap_header(&$header)
{
????assert(is_array($header));
????
????if($header[‘pid‘]?!==?0)
????{
????????return?false;
????}
????
????if($header[‘len‘]??(MODBUS_TCP_MAX_ADU_SIZE?-?MBAP_HEADER_SIZE?+?1))?
????{???????
????????return?false;
????}????????
????
????return?true;
}
//check?response?from?
function?modbus_tcp_check_read_reg_response_pdu(&$pdu?$func?&$excepti
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