GE VersaMax PLC User Manual page 280

Words
15
Control Word
(Address + 14)
If the Override bit (bit 0) is set to 1, the Control Word and the
internal SP, PV and CV parameters must be used for remote
operation of the PID block (see below). This allows a remote
operator interface device, such as a computer, to take control
away from the PLC program.
Caution: If you do not want to allow remote operation of the
PID block, make sure the Control Word is set to 0. If the low
bit is 0, the next 4 bits can be read to track the status of the
PID input contacts as long as the PID Enable contact has
power. Control Word is a discrete data structure with the first
five bit positions defined in the following format:
Bit
0
1
2
3
4
16 Internal SP
(Address + 15) Tracks the SP input. If Override = 1, must be set externally to
solve the PID algorithm using an alternate SP value. The
original SP value is maintained until overwritten.
17 Internal CV
(Address + 16) Tracks CV output.
18 Internal PV
(Address + 17) Tracks PV input. Must be set externally if Override bit is set to
1.
280 GFK-1503E
For public disclosure
Parameter/Description
Word Function Status or External Action if
Value
Override bit is set to 1
1 Override If 0, monitor block contacts
below. If 1, set them
externally.
2 Manual / If 1, block is in Manual mode.
Auto If other numbers, it is in
Automatic mode.
4 Enable Should normally be 1.
Otherwise, block is never
called.
8 UP / Raise If 1 and Manual (bit 1) is 1,
CV is incremented every
solution.
16 DN / Lower If 1 and Manual (bit 1) is 1,
CV is decremented every
solution.
Low Bit Range
Units
Maintained by Boolean
the CPU,
unless bit 0
(Override) is
set to 1.
Set and Non-configurable,
maintained by unless bit 1 0
the CPU, (Override) of Control
unless bit 1 0 Word is set to 1.
(Override) of
Control Word
is set to 1.
Set and Non-configurable.
maintained by
the CPU.
Set and Non-configurable
maintained by unless bit 10
the CPU, (Override) of Control
unless bit 10 Word is set to 1.
(Override) of
Control Word
is set to 1.
VersaMax PLC User Manual