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- 1 - Read Coils: reading of binary status - KOM process sends values of I/O tags of Do type.
- 2 - Read Discrete Inputs: reading of binary inputs - KOM process sends values of I/O tags of Do type.
- 3 - Read Holding Registers: reading of status registers - KOM process sends values of I/O tags of Co, Ao type (signed/unsigned).
- 4 - Read Input Registers: reading of input registers - KOM process sends values of I/O tags of Co, Ao type (signed/unsigned).
- 5 - Write Single Coil: writing of binary statuses - KOM process writes a received binary value in I/O tag of Di, Do type into system.
- 15 - Write Multiple Coils - KOM process writes all received binary values of the I/O tag of Di, Do type into the system.
- 6 - Write Single Register: writing of status registers - KOM process writes the received value in the I/O tag of Ai, Ao, Ci, Co type into the system.
- 16 - Write Multiple registers: writing of multiple registers - KOM process writes all received values in the I/O tags of Ai, Ao, Ci, Co type into the system.
- 22 - Mask Write Register: writing the register with the AND/OR mask - KOM process writes the received value in the I/O tag of Ai, Ao, Ci, Co type into the system.
Note: This is a server type of protocol that is primarily intended for sending the values out of the D2000 system. Therefore the I/O tags should be configured as an output (Ao, Co, Do) because of the manipulation of their values directly or by control objects. If the I/O tag is configured as input (Ai, Ci, Di), the KOM process is unable to send a valid value in a reply to reading by functions 1 - 4 until the value is written by function functions 5, 15, 6, 16. or 16 22 from outside.
If the KOM process does not have the valid value of I/O tag or request to read a nonexistent I/O tag is received, an implicit value False or 0 is sent as a response to a read request (MODBUS protocol does not support the transfer of value quality).
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