Installation manual

Publication 1747-RM001G-EN-P - November 2008
A-8 SLC 5/03 (OS30x), SLC 5/04 (OS40x) and SLC 5/05 (OS50x) Firmware History
instruction moves the current value of the 10uS free running clock into
the destination address. If it is an integer address, it only moves the least
16 bits into the address. If it is a float address, it converts the long
integer value into a float and moves it to the relative address. After the
free running clock reaches 0xfffff value (10.4857 sec), it will wrap
around to 0 and continues incrementing. The RESET signal or Power
Cycle will set this free running clock to 0.
• Compute Time Difference Instruction (TDF)
The compute Time Difference Instruction (TDF) is used to calculate
the elapsed time between any 2 timestamps captured using the RHC
instruction. This allows the user program to time any event using a 10uS
timebase.
When the TDF is evaluated with a false rungstate, during pre-scan, or
inside a false MCR zone, no operation is performed. When the TDF is
evaluated with a true rungstate, the instruction calculates the number of
10uS “ticks” that have elapsed from the Start value to the Stop value
and places the result into the Destination. The TDF instruction with
float address will accurately compute the time difference between any 2
timestamps captured within 10.48575 seconds of each other (1048575
10uS ticks). The TDF with float address will calculate an invalid result if
more than 10.48575 seconds have elapsed between the start and stop
timestamps. Meanwhile, the TDF instruction with integer address will
compute the positive time difference between the START and END
timestamps. The TDF with integer address will calculate an invalid
result if more than 327.67ms have elapsed between the start and stop
timestamps.
• Encode 1 of 16 to 4 Instruction (ENC)
The ENC instruction provides the ability to give the first set bit position
in an integer value.
When the rung is true, this output instruction searches the source from
the lowest to the highest bit, and looks for the first set bit. The
corresponding bit position is written to the destination integer.
• Ramp Instruction (RMP)
The Ramp (RMP) instruction provides the ability to create linear,
acceleration, deceleration, and “S” curve ramp output data wave forms.
The instruction provides a means to ramp analog outputs when using
them to control devices such as valves.
When the Ramp function is triggered, parameters are validated to be in
range. If the parameters are valid, the ramp function places the
Beginning Output Value in the Destination register. The format of the
control block will be defined as part of the development process. It is