CTI 2572-B / 2500C-2572-B Installation and Operation Manual 92
Command Status Word
The Command Status Word contains bits that are set by the module. The following illustration indicates how
the bits within the word are used.
COMMAND STATUS WORD (WX2)
Command Error. The 2572-B sets this bit when it encounters an error while
attempting to execute the command. The 2572-B will write an error code into
Offset 0 of the command block unless PLC
RR
PLC Read/Write Error. The 2572-B sets this bit to indicate that it could not read a
valid command block from V memory. Therefore, there is no place to write an
error word. This may be caused by loading a value in the Command Slot which is
not a valid V memory location (such as 0) or which points to V memory that does
not contain a Command Block.
Indicates the module is in the process of executing a command.
Indicates the module is attempting to abort a command.
Command Slots (WY5-WY8)
Module words WY5, WY6, WY7, and WY8 are called Command Slots. There are four command slots, one for
each possible concurrent command. The value in the command slot points to the V memory address of a
command block as illustrated below. Addresses of 0 or less are invalid. Addresses greater than 64k cannot be
referenced.
COMMAND SLOTS
Command Slot 1: V Memory Address of Command Block for CMD1
Command Slot 2: V Memory Address of Command Block for CMD2
Command Slot 3: V Memory Address of Command Block for CMD3
Command Slot 4: V Memory Address of Command Block for CMD4
Note that the command slots match up with the command control and command status bits in WY4 and WX2.
For example, the command block whose address in Command Slot 1 will be triggered by setting bit 3 in WY4
(Bit 3 is the Command Trigger for Command 1).
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