/* This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * */ /** library to query measurements from eastron SDM120-ModBus electricity meter (code) * @file sensor_sdm120.c * @author King Kévin * @date 2016 * @note peripherals used: USART @ref sensor_sdm120_usart , GPIO @ref sensor_sdm120_gpio , timer @ref sensor_sdm120_timer */ /* standard libraries */ #include // standard integer types #include // general utilities #include // mathematical utilities /* STM32 (including CM3) libraries */ #include // real-time control clock library #include // general purpose input output library #include // universal synchronous asynchronous receiver transmitter library #include // timer utilities #include // interrupt handler #include // Cortex M3 utilities #include "sensor_sdm120.h" // SDM120 electricity meter header and definitions #include "global.h" // common methods /** @defgroup sensor_sdm120_usart USART peripheral used for communication with electricity meter * @{ */ #define SENSOR_SDM120_USART 3 /**< USART peripheral */ /** @} */ /** @defgroup sensor_sdm120_gpio GPIO peripheral used for controlling RS-485 adapter * @note driver output is enabled on high while receiver output is enabled on low, thus one pin can be used to control both * @{ */ #define SENSOR_SDM120_REDE_PORT B /**< GPIO port for RS-485 receiver and driver output enable signal */ #define SENSOR_SDM120_REDE_PIN 12 /**< GPIO pin for RS-485 receiver and driver output enable signal */ /** @} */ /** @defgroup sensor_sdm120_timer timer peripheral to enforce waiting time between messages * @note 60 ms are recommended between messages in SDM630 ModBus protocol implementation and this seem to also apply to SDM120 * @{ */ #define SENSOR_SDM120_TIMER 3 /**< timer number to count time */ /** @} */ /* input and output ring buffer, indexes, and available memory */ static uint8_t rx_buffer[9] = {0}; /**< buffer for received response (ModBus response messages can be 2+256+2 long but we will only read up to 2 registers) */ static volatile uint8_t rx_used = 0; /**< number of received data bytes in buffer */ static uint8_t tx_buffer[13] = {0}; /**< buffer for request to transmit (ModBus request messages can be 7+256+2 long but we will only write up to 2 registers */ static volatile uint8_t tx_used = 0; /**< number of byte to transmit */ volatile bool sensor_sdm120_measurement_received = false; /** the ModBus timeouts to respect for sending messages **/ static enum timeout_t { TIMEOUT_BEGIN = 0, /**< silent time before sending data */ TIMEOUT_END, /**< silent time after sending data */ TIMEOUT_BETWEEN, /**< time to wait between messages */ TIMEOUT_MAX /**< last element (useful to no the number of elements) */ } timeout; /**< the current timeout used */ /** current timeout used */ static uint16_t timeout_times[TIMEOUT_MAX] = {0}; /** SDM120 3xxxx input register start addresses for the measurement types */ static const uint16_t register_input[] = { 0x0000, // 30001 voltage (in volts) 0x0006, // 30007 current (in amperes) 0x000c, // 30013 active power (in watts) 0x0012, // 30019 apparent power (in volt amperes) 0x0018, // 30025 reactive power (in volt amperes reactive) 0x001e, // 30031 power factor (0-1) 0x0046, // 30071 frequency (in hertz) 0x0048, // 30073 import active energy (in kWh) 0x004a, // 30075 export active energy (in kWh) 0x004c, // 30077 import reactive energy (in kVArh) 0x004e, // 30079 export reactive energy (in kVArh) 0x0156, // 30343 total active energy (in kWh) 0x0158 // 30345 total reactive energy (in kVArh) }; /** SDM120 4xxxx holding register start addresses for the configuration types */ static const uint16_t register_holding[] = { 0x000c, // relay pulse width (60, 100, or 200 ms) 0x0012, // network parity stop (0: 1 stop bit no parity, 1: one stop bit even parity, 2: one stop bit odd parity, 3: two stop bits no parity) 0x0014, // meter slave address (1-247) 0x001c, // baud rate (0: 2400 bps, 1: 4800 bps, 2: 9600 bps, 5: 1200 bps) 0x0056, // pulse 1 output mode (1: import active energy, 2: import+export active energy, 4: export active energy, 5: import reactive energy, 6: import+export reactive energy, 8: export reactive energy) 0xf900, // time of scroll display (0-30 s) 0xf910, // pulse 1 output (0: 0.001 kWh/imp, 1: 0.01 kWh/imp, 2: 0.1 kWh/imp, 3: 1 kWh/imp) 0xf920 // measurement mode (1: total=import, 2: total=import+export, 3: total=import-export) }; /** compute CRC for ModBus * @note ModBus uses ANSi/IBM 16-bits CRC (with normal polynomial 0x8005, reverse polynomial 0xA001, start value 0xfff) * @param[in] buffer data on which to compute the CRC for * @param[in] size number of byte to compute the CRC for * @return computed CRC checksum */ static uint16_t crc_modbus(uint8_t* buffer, uint8_t size) { uint16_t crc = 0xffff; // initial value (for ModBus) for (uint8_t i=0; i>1)^0xA001; // // shift to the right (for the next bit) and XOR with (reverse) polynomial } else { crc >>= 1; // just shift right (for the next bit) } } } return crc; } void sensor_sdm120_setup(uint32_t baudrate) { // enable USART I/O peripheral rcc_periph_clock_enable(RCC_AFIO); // enable pin alternate function (USART) rcc_periph_clock_enable(USART_PORT_RCC(SENSOR_SDM120_USART)); // enable clock for USART port peripheral rcc_periph_clock_enable(USART_RCC(SENSOR_SDM120_USART)); // enable clock for USART peripheral gpio_set_mode(USART_PORT(SENSOR_SDM120_USART), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, USART_PIN_TX(SENSOR_SDM120_USART)); // setup GPIO pin USART transmit gpio_set_mode(USART_PORT(SENSOR_SDM120_USART), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, USART_PIN_RX(SENSOR_SDM120_USART)); // setup GPIO pin USART receive gpio_clear(USART_PORT(SENSOR_SDM120_USART), USART_PIN_RX(SENSOR_SDM120_USART)); // pull down to avoid noise when not connected (it will be set low by RS485 chip when RO is enabled) // setup USART parameters for electricity meter usart_set_baudrate(USART(SENSOR_SDM120_USART), baudrate); // get baud rate by scrolling through the measurements on the electricity meter's screen (default 2400) usart_set_databits(USART(SENSOR_SDM120_USART), 8); usart_set_stopbits(USART(SENSOR_SDM120_USART), USART_STOPBITS_1); usart_set_mode(USART(SENSOR_SDM120_USART), USART_MODE_TX_RX); usart_set_parity(USART(SENSOR_SDM120_USART), USART_PARITY_NONE); // get parity by scrolling through the measurements on the electricity meter's screen (default none) usart_set_flow_control(USART(SENSOR_SDM120_USART), USART_FLOWCONTROL_NONE); nvic_enable_irq(USART_IRQ(SENSOR_SDM120_USART)); // enable the USART interrupt usart_enable_rx_interrupt(USART(SENSOR_SDM120_USART)); // enable receive interrupt usart_enable(USART(SENSOR_SDM120_USART)); // enable USART // setup GPIO rcc_periph_clock_enable(RCC_GPIO(SENSOR_SDM120_REDE_PORT)); // enable clock for GPIO peripheral gpio_set_mode(GPIO(SENSOR_SDM120_REDE_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(SENSOR_SDM120_REDE_PIN)); // setup GPIO pin for receiver and driver output enable pin gpio_clear(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // disable driver output and enable receive output // setup timer to wait for minimal time before next transmission rcc_periph_clock_enable(RCC_TIM(SENSOR_SDM120_TIMER)); // enable clock for timer block timer_reset(TIM(SENSOR_SDM120_TIMER)); // reset timer state timer_set_mode(TIM(SENSOR_SDM120_TIMER), TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock,edge alignment (simple count), and count up timer_one_shot_mode(TIM(SENSOR_SDM120_TIMER)); // stop counter after update event (we only need to count down once) timer_set_prescaler(TIM(SENSOR_SDM120_TIMER), 66-1); // set the prescaler so this 16 bits timer allows to wait for 60 ms ( 1/(72E6/66/(2**16))=60.07ms ) timeout_times[TIMEOUT_BEGIN] = (rcc_ahb_frequency/(TIM_PSC(TIM(SENSOR_SDM120_TIMER))+1))/baudrate/8/2.5; // wait at least 2.5 characters before sending data timeout_times[TIMEOUT_END] = (rcc_ahb_frequency/(TIM_PSC(TIM(SENSOR_SDM120_TIMER))+1))/baudrate/8/2.5; // wait at least 2.5 characters after sending data timeout_times[TIMEOUT_BETWEEN] = 0.06*(rcc_ahb_frequency/(TIM_PSC(TIM(SENSOR_SDM120_TIMER))+1)); // wait at least 60 ms before sending the next message timer_clear_flag(TIM(SENSOR_SDM120_TIMER), TIM_SR_UIF); // clear flag timer_enable_irq(TIM(SENSOR_SDM120_TIMER), TIM_DIER_UIE); // enable update interrupt for timer nvic_enable_irq(NVIC_TIM_IRQ(SENSOR_SDM120_TIMER)); // catch interrupt in service routine // reset states tx_used = 0; rx_used = 0; sensor_sdm120_measurement_received = false; } /** send request to electricity meter * @param[in] meter_id electricity meter device id (ModBus salve address) * @param[in] function ModBus function: 0x03 read two 16 bits holding registers, 0x04 read two 16 bits input registers, 0x10 write two 16 bits holding registers * @param[in] address register start point address * @param[in] value value to store in holding register (if function 0x10 is used) * @return if request is correct and transmission started */ static bool sensor_sdm120_transmit_request(uint8_t meter_id, uint8_t function, uint16_t address, float value) { if (meter_id==0) { // broadcast request are not supported return false; } if (function!=0x03 && function!=0x04 && function!=0x10) { // function not supported return false; } if (address%2) { // even register addresses are not supported by device return false; } while (tx_used) { // transmission is ongoing __WFI(); // wait until something happens (transmission ended) } // build request packet uint8_t packet[11]; // buffer to build ModBus message (without error check) uint8_t packet_size = 0; // ModBus message size (without error check) packet[0] = meter_id; // set slave device address packet[1] = function; // set function packet[2] = address>>8; // set high register address packet[3] = address; // set low register address packet[4] = 0; // set high number of registers to read packet[5] = 2; // set low number of register to read (the measurement are encoded using 32 bits IEE745 float, and register hold 16 bits, thus we want to read 2 registers if (function==0x03 || function==0x04) { // read register packet_size = 6; // set message size } else if (function==0x10) { // write register packet[6] = 4; // byte count (writing two 16 bits registers) // store little endian encoded value in big endian encoded data uint8_t* data = (uint8_t*)&value; packet[7] = data[3]; packet[8] = data[2]; packet[9] = data[1]; packet[10] = data[0]; packet_size = 11; // set message size } uint16_t crc = crc_modbus(packet, packet_size); // compute error check for (uint8_t i=0; i>8; // set high error check tx_used = packet_size+2; // set request size rx_used = 0; // reset reset buffer sensor_sdm120_measurement_received = false; // reset measurement flag while (TIM_CR1(TIM(SENSOR_SDM120_TIMER))&TIM_CR1_CEN) { // timer is already used __WFI(); // wait until something happens (timer is available again) } gpio_set(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // enable driver output and disable receive output // start timeout timeout = TIMEOUT_BEGIN; // select time before sending message timer_set_period(TIM(SENSOR_SDM120_TIMER), timeout_times[timeout]); // set corresponding timeout timer_set_counter(TIM(SENSOR_SDM120_TIMER), 0); // reset timer counter to get preset waiting time timer_enable_counter(TIM(SENSOR_SDM120_TIMER)); // wait return true; } bool sensor_sdm120_measurement_request(uint8_t meter_id, enum sensor_sdm120_measurement_type_t type) { if (type>=SENSOR_SDM120_MEASUREMENT_MAX) { // invalid type return false; } return sensor_sdm120_transmit_request(meter_id, 0x04, register_input[type], 0); } bool sensor_sdm120_configuration_request(uint8_t meter_id, enum sensor_sdm120_configuration_type_t type) { if (type>=SENSOR_SDM120_CONFIGURATION_MAX) { // invalid type return false; } return sensor_sdm120_transmit_request(meter_id, 0x03, register_holding[type], 0); } bool sensor_sdm120_configuration_set(uint8_t meter_id, enum sensor_sdm120_configuration_type_t type, float value) { if (type>=SENSOR_SDM120_CONFIGURATION_MAX) { // invalid type return false; } return sensor_sdm120_transmit_request(meter_id, 0x10, register_holding[type], value); } float sensor_sdm120_measurement_decode(void) { float measurement = NAN; // decoded measurement to return (invalid in the beginning) if (!sensor_sdm120_measurement_received) { // no measurement received return NAN; } else { sensor_sdm120_measurement_received = false; // reset flag } if (rx_used<5) { // not a complete response (minimum is address, function, size/error, error check low, error check high) return NAN; } // a complete message has been received if (crc_modbus(rx_buffer,rx_used)) { // checksum error, error check failed measurement = NAN; } else if (rx_buffer[1]&0x80) { // error condition received measurement = INFINITY; // indicate we received and error } else { switch (rx_buffer[1]) { case 0x03: // read 4xxx holding register response received case 0x04: // read 3xxxx input register response received if (rx_buffer[2]==0x04 && rx_used>=(4+5)) { // 2 registers received, corresponds to implemented request // convert big endian received float value to little endian return value uint8_t* convert = (uint8_t*)&measurement; convert[0] = rx_buffer[6]; convert[1] = rx_buffer[5]; convert[2] = rx_buffer[4]; convert[3] = rx_buffer[3]; } break; case 0x10: // write 4xxx holding register response received measurement = (rx_buffer[4]<<8)+rx_buffer[5]; // number of registers written break; // not supported currently default: // unknown function response received measurement = INFINITY; break; // nothing to do } } rx_used = 0; // reset rx_buffer usage return measurement; } /** USART interrupt service routine called when data has been transmitted or received */ void USART_ISR(SENSOR_SDM120_USART)(void) { if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_TXE)) { // data has been transmitted if (tx_used) { // not all bytes transmitted usart_send(USART(SENSOR_SDM120_USART),tx_buffer[--tx_used]); // transmit next byte (clears flag) } else { // all bytes transmitted usart_disable_tx_interrupt(USART(SENSOR_SDM120_USART)); // disable transmit interrupt USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_TXE; // clear flag USART_CR1(USART(SENSOR_SDM120_USART)) |= USART_CR1_TCIE; // enable transfer complete interrupt } } if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_TC)) { // data has been completely transmitted USART_CR1(USART(SENSOR_SDM120_USART)) |= USART_CR1_TCIE; // disable transfer complete interrupt USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_TC; // clear flag timeout = TIMEOUT_END; // select wait time after sending data timer_set_period(TIM(SENSOR_SDM120_TIMER), timeout_times[timeout]); // set corresponding timeout timer_set_counter(TIM(SENSOR_SDM120_TIMER), 0); // reset timer counter to get preset waiting time timer_enable_counter(TIM(SENSOR_SDM120_TIMER)); // wait } if (usart_get_interrupt_source(USART(SENSOR_SDM120_USART), USART_SR_RXNE)) { // data has been received if (gpio_get(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN))) { // not in receiver mode USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_RXNE; // clear flag, ignore received data } else if (rx_used=5 && (rx_buffer[1]&0x80)) { // error condition response received sensor_sdm120_measurement_received = true; // notify used response has been received } else if (rx_used>=5 && (uint8_t)(rx_used-5)>=rx_buffer[2] && (rx_buffer[1]==0x04 || rx_buffer[1]==0x03)) { // read input or holding register response received sensor_sdm120_measurement_received = true; // notify used response has been receive } else if (rx_used>=8 && rx_buffer[1]==0x10) { // write holding register response received sensor_sdm120_measurement_received = true; // notify used response has been receive } } else { // buffer full and unknown response received USART_SR(USART(SENSOR_SDM120_USART)) &= ~USART_SR_RXNE; // clear flag (wait for user to read measurement, this clears the buffer) } timeout = TIMEOUT_END; // select time after receiving data timer_set_period(TIM(SENSOR_SDM120_TIMER), timeout_times[timeout]); // set corresponding timeout timer_set_counter(TIM(SENSOR_SDM120_TIMER), 0); // reset timer counter to get preset waiting time timer_enable_counter(TIM(SENSOR_SDM120_TIMER)); // wait } } /** interrupt service routine called on timeout */ void TIM_ISR(SENSOR_SDM120_TIMER)(void) { if (timer_get_flag(TIM(SENSOR_SDM120_TIMER), TIM_SR_UIF)) { // update event happened timer_clear_flag(TIM(SENSOR_SDM120_TIMER), TIM_SR_UIF); // clear flag // because of the one pulse mode the timer is stopped automatically switch (timeout) { // timeout before action passed case (TIMEOUT_BEGIN): // we can now send the data USART_SR(USART(SENSOR_SDM120_USART)) &= USART_SR_TXE; // clear interrupt flag usart_enable_tx_interrupt(USART(SENSOR_SDM120_USART)); // enable interrupt to send other bytes usart_send(USART(SENSOR_SDM120_USART),tx_buffer[--tx_used]); // start transmission break; case (TIMEOUT_END): // we now have to wait before sending the next message gpio_clear(GPIO(SENSOR_SDM120_REDE_PORT),GPIO(SENSOR_SDM120_REDE_PIN)); // disable driver output (and enable receive output) timeout = TIMEOUT_BETWEEN; // select time between sending message timer_set_period(TIM(SENSOR_SDM120_TIMER), timeout_times[timeout]); // set corresponding timeout timer_set_counter(TIM(SENSOR_SDM120_TIMER), 0); // reset timer counter to get preset waiting time timer_enable_counter(TIM(SENSOR_SDM120_TIMER)); // wait case (TIMEOUT_BETWEEN): // nothing to do, we are allowed to send the next message break; default: break; } } }