User Manual UMAX030541. Version V1 17-116
1.4.
Lookup Table Function Block
The lookup table (LTyz) function blocks are not used by default, where yz can be 01 to
10.
Figure 6
– Lookup Table Objects
Lookup tables are used to give an output response of up to 10 slopes per input.
The array size of the objects 3yz5h
LTyz Point Response
, 3yz6h
LTyz Point X-Axis PV
and 3yz7h
Point Y-Axis PV
shown in the block diagram above is therefore 11.
Note: If more than 10 slopes are required, a Programmable Logic Block can be used to
combine up to three tables to get 30 slopes, as is described in Section 1.5.
A parameter that will affect the function block is object 3yz5h
LTyz Point Response
sub-
index 1
which defines the “
X-Axis Type
”. By default, the table have a
‘Data Response’
output (0). Alternatively, it can be selected as a
‘Time Response’
(1).
There are two (or three) other key parameters that will affect how this function block will
behave depending on the
“
X-Axis Type
” chosen. If chosen
‘Data Response’
, then the
objects 3yz0h
Lookup Table yz Input X-Axis Source
and
3yz1h
Lookup Table yz Input
X-Axis Number
together define the control source for the function block. When it is
changed, the table values in object 3yz6h and 3yz3h
LTyz X-Axis Decimal Digits PV
need to be updated with new defaults based on the X-Axis source selected as described
in Tables 5 and 6.
If however, the “
X-Axis Type
” is chosen to be
‘Time Response’
, an
additional parameter is taken into consideration - object 3yz2h,
Lookup Table yz Auto
Repeat
. These will be described in more detail in Section 1.4.4.
