Response Electronics CL6011B Especificaciones descargar pdf (Pagina 269)

5Ć7Configuration Tips

Original Ć June 1990 CE4.2:CL6211

5.3.2 Scratch Registers

Setting aside two to three general registers as scratch" registers is

another method which may be used to conserve the number of registers

required to implement a control strategy. A scratch register is a register

which may be used multiple times for different purposes during an FSTs

execution. Generally the scratch register holds intermediate results for

use by subsequent FST instructions. Consider the following examples

where it is necessary to implement the boolean logic of DI 1 OR DI 2,

and have the inputs tunable for normally open/normally closed contacts:

Example 1:

DI ( 1 ),

XOR ( DI1_NOT ),

RGST ( DI1 ),

DI ( 2 ),

XOR ( DI2_NOT ),

OR ( DI1 ),

Using this technique it is necessary to use one register to store the

status of DI 1.

Example 2:

DI ( 1 ),

XOR ( DI1_NOT ),

RGST ( SCRATCH ),

DI ( 2 ),

XOR ( DI2_NOT ),

OR ( SCRATCH ),

The second method uses a scratch register. After the OR instruction, the

results later in the FST.

5.3.3 Split Registers

Every general register in a continuous controller is made up of an analog

portion and a discrete portion. Registers are normally named and used

for one specific function, many times using only the analog portion or the

discrete portion, but not both. It is possible to take advantage of this

situation by doubling up on the usage of registers.

Example:

The analog portion of a reference register contains a fuel BTU value for

use in calculations within the FST. It is also desired to tune the discrete

logic of a discrete input. The analog portion of the register could be

used for the BTU value, and the discrete portion of the register could be

used for the discrete input logic tuning.

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Response Electronics CL6011B Especificaciones Pagina 269