Spectrum Controls 2080sc-BAC - Manual (Page 35)

Chapter 3: Configuring the Module 3-17
User’s Manual Pub. 0300274-01 Rev. A.0
tmp2 := AND_MASK (tmp2, 1 );
IF tmp2 = 1 THEN
tmp_raw_var := 1 ;
ELSE
tmp_raw_var := 0 ;
END_IF ;
(*
if param_mode == 3
This is for Binary Input Table
*)
ELSIF param_mode = 3 THEN
tmp_index := param_offset / 8 ;
tmp1 := MOD (param_offset, 8 );
tmp2 := 1 ;
tmp2 := SHL (tmp2, tmp1);
tmp1 := ANY_TO_DINT(bac_raw_tbl[tmp_index]);
IF param_var = 0 THEN (* set 0 *)
tmp1 := NOT_MASK (tmp1);
tmp1 := OR_MASK (tmp1, tmp2);
tmp1 := NOT_MASK (tmp1);
ELSE (* set 1 *)
tmp1 := OR_MASK (tmp1, tmp2);
END_IF ;
bac_raw_tbl[tmp_index] := ANY_TO_BYTE(tmp1);
ELSE
(* do nothing *)
(* tmp_index := param_offset / 8; *)
END_IF ;
In the Main function, you see a variable called bacnet_convert_fn type as
BACNET_Convert is called. This is how the Main function calls the user-defined
function block.
Since CCW has many different types of data types, this function block is able to
convert all the different data types to a bytes array. When CCW reads from the
module, the module fills this bytes array first. Then CCW reads the array and
converts the data to different data types. When CCW writes to the module, CCW
converts a variable to this 8 bytes array, and writes it to the module. The
following examples shows how an analog output variable is read from module,
and an analog input variable is written to the module from CCW. Structured text
is generated by the module.
A variable called tag1 is converted to ULINT variable bacnet_convert_var
and then placed at offset 0 of the byte array table because you are writing
AnalogInput 0. If it is AnalogInput 1, the offset will be 8 as each BACNET
object instance takes 8 bytes. Variable
bacnet_convert_mode is 1 means this
is a write operation. 0 indicates a read operation.
(* 0, AnalogInput, aiaaa *)
bacnet_convert_var := ANY_TO_ULINT(tag1);
bacnet_convert_offset := 0;
bacnet_convert_mode := 1;
bacnet_convert_fn(bacnet_convert_offset,
bacnet_convert_var, bacnet_convert_mode);