Process control channels may be associated with five IODDTs, depending of the process control type :
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T_PROC_PLOOP specific to the process loop,
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T_PROC_3SING_LOOP specific to 3 single-loop processes,
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T_PROC_CASC_LOOP specific to cascade-type loops,
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T_PROC_SPP specific to setpoint programmers,
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T_PROC_CONST_LOOP specific to auto-selector loops.
Each IODDT includes a series of language objects used to drive and monitor the operation of control loops. These objects are automatically exchanged at each cycle of the task assigned to the control loops.
NOTE: IODDT variables can be created in two different ways:
