writeMultipleCoils method

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

Write multiple coils (FC 15).

Forces each coil in a sequence to either ON or OFF.

Parameters:

• slaveId: The slave device ID (0-247, 0 for broadcast)
• address: Starting address of coils
• quantity: Number of coils to write (1-1968)
• value: Byte array with coil values (bit-packed)

Example:

final values = Uint8List.fromList([0xFF, 0x00]); // First 8 ON, next 8 OFF
await client.writeMultipleCoils(1, 0, 16, values);

Implementation

@override
Future<void> writeMultipleCoils(
    int slaveId, int address, int quantity, Uint8List value) async {
  if (slaveId > _addressMax) {
    throw ArgumentError(
        'modbus: slaveId \'$slaveId\' must be between \'$addressBroadCast\' and \'$_addressMax\'');
  }
  if (quantity < writeBitsQuantityMin || quantity > writeBitsQuantityMax) {
    throw ArgumentError(
        'modbus: quantity \'$quantity\' must be between \'$writeBitsQuantityMin\' and \'$writeBitsQuantityMax\'');
  }
  if (value.length * 8 < quantity) {
    throw ArgumentError(
        'modbus: value bits size \'${value.length * 8}\' does not greater or equal to quantity \'$quantity\'');
  }

  final response = await send(
    slaveId,
    ProtocolDataUnit(
      funcCodeWriteMultipleCoils,
      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\'');
  }
}