Instrumentation control system

An instrumentation control system, comprising:

• a first field device;
• and
• a second field device coupled to the first field device via a fieldbus to allow bidirectional communication, wherein the first field device comprises:
• a transmitting buffer to store data to be transmitted to the second field device;
• a transmitter to transmit the data to the second field device;
• and
• an inquiry processing section to cause the transmitter to retransmit the data stored in the transmitting buffer to the second field device in response to a data retransmission request from the second field device, and the second field device comprises:
• a receiving buffer to store the data transmitted from the first field device;
• a checking section to determine whether the data stored in the receiving buffer is normal or not, and to make a data retransmission request to the first field device if the data stored in the receiving buffer is not normal;
• and
• a processing unit to perform predetermined processing based on the data which is determined to be normal by the checking section.