writeMultipleRegistersBytes method

@override Future<void> writeMultipleRegistersBytes(int slaveId, int address, int quantity, Uint8List value,)

Write multiple registers from bytes (FC 16).

Writes 1 to 123 contiguous holding registers.

Parameters:

• slaveId: The slave device ID (0-247, 0 for broadcast)
• address: Starting address of registers
• quantity: Number of registers to write (1-123)
• value: Raw bytes (must be quantity × 2 bytes, big-endian)

Implementation

@override
Future<void> writeMultipleRegistersBytes(
    int slaveId, int address, int quantity, Uint8List value) async {
  if (slaveId > _addressMax) {
    throw ArgumentError(
        'modbus: slaveId \'$slaveId\' must be between \'$addressBroadCast\' and \'$_addressMax\'');
  }
  if (quantity < writeRegQuantityMin || quantity > writeRegQuantityMax) {
    throw ArgumentError(
        'modbus: quantity \'$quantity\' must be between \'$writeRegQuantityMin\' and \'$writeRegQuantityMax\'');
  }
  if (value.length != quantity * 2) {
    throw ArgumentError(
        'modbus: value length \'${value.length}\' does not twice as quantity \'$quantity\'');
  }

  final response = await send(
    slaveId,
    ProtocolDataUnit(
      funcCodeWriteMultipleRegisters,
      pduDataBlockSuffix(value, [address, quantity]),
    ),
  );

  if (response.data.length != 4) {
    throw Exception(
        'modbus: response data size \'${response.data.length}\' does not match expected \'4\'');
  }

  final rspAddress = bytesToUint16(response.data.sublist(0, 2))[0];
  if (rspAddress != address) {
    throw Exception(
        'modbus: response address \'$rspAddress\' does not match request \'$address\'');
  }

  final rspQuantity = bytesToUint16(response.data.sublist(2, 4))[0];
  if (rspQuantity != quantity) {
    throw Exception(
        'modbus: response quantity \'$rspQuantity\' does not match request \'$quantity\'');
  }
}