GE 90-30/20/Micro manual Special Note on Certain Bit Operations, 15 14 13 12 11 10 9 5 4 3 2 1

4

The control word stores the state of the boolean inputs and outputs of its associated function block, as shown in the following format:

15 14 13 12 11 10 9 8

7 6 5 4 3 2 1 0

Reserved

Reset input

Reserved

Enable input, previous execution

Q (counter/timer status output)

EN (enable input)

Bits 0 through 11 are used for timer accuracy; bits 0 through 11 are not used for counters.

Note

Use care if you use the same address for PV as the second word in the block of three words. If PV is not a constant, the PV is normally set to a different location than the second word. Some applications choose to use the second word address for the PV, such as using %R0102 when the bottom data block starts at %R0101. This allows an application to change the PV while the timer or counter is running. Applications can read the first CV or third Control words, but the application cannot write to these values, or the function will not work.

Special Note on Certain Bit Operations

When using the Bit Test, Bit Set, Bit Clear or Bit Position function, the bits are numbered 1 through 16, NOT 0 through 15 as shown above.

4-10 Series 90-30/20/Micro Programmable Controllers Reference Manual–September 1998 GFK-0467K