UMAX140610. LIN
– J1939 CAN Protocol Converter with PWM Output. Version 1
Page: 29-81
selected. However, there are 2 more setpoints “
X Decimal Digits
” and “
Y Decimal Digits
” that
might affect the point values. These 2 setpoints will change the resolution of the X Values or Y
Values, respectively, with the decimal digits value user chooses. Keep in mind that any change
on the decimal digits will make effect to the current X values or Y values.
Initialize the Control Source of a Lookup Table BEFORE changing the table
values, as the new settings WILL get erased when the control is updated.
The second setpoint that will affect the function block (i.e. reset to
defaults), is the “
X-Axis
Type
”. By default, the tables have a
‘Data Response’
output. Alternatively, it can be selected
as a
‘Time Response’,
which is described later in Section 3.4.5.
3.4.1 X-Axis, Input Data Response
In the case where the
X-Axis Type
” =
‘Data Response’,
the points on the X-Axis represents
the data of the control source.
For example, if the control source is a CAN Receive message, setup as a 0-5V type, with an
operating range of 0.5V to 4.5V, the X-
Axis will be setup to have a default “
Point 1
– X Value
”
of 0.5V, and setpoint “
Point 10
– X Value
” will be set to 4.5V. The “
Point 0
– X Value
” will be
set to the default value of 0.0V.
For most
‘Data Responses’, the default value at point (0,0) is [0,0].
However, should the minimum input be less than zero, for example a CAN message that is
reflecting temperature in the range of -
40ºC to 210ºC, then the “
Point 0
– X Value
” will be set
to the minimum instead, in this case -40ºC.
The constraint on the X-Axis data is that the next index value is greater than or equal to the
one below it, as shown in the equation below. Therefore, when adjusting the X-Axis data, it is
recommended that X
10
is changed first, then lower indexes in descending order.
MinInputRange <= X
0
<= X
1
<= X
2
<= X
3
<= X
4
<= X
5
<= X
6
<= X
7
<= X
8
<= X
9
<= X
10
<=
MaxInputRange
As stated earlier, MinInputRange and MaxInputRange will be determined by the X-Axis Source
that has been selected.
If some of the data points are
‘Ignored’
as described in Section 3.4.4, they will not be used in
the X-Axis calculation shown above. For example, if points X
4
and higher are ignored, the
formula becomes MinInputRange <= X
0
<= X
1
<= X
2
<= X
3
<= MaxInputRange instead.
3.4.2 Y-Axis, Lookup Table Output
The Y-Axis has no constraints on the data that it represents. This means that inverse,
increasing/decreasing or other responses can be easily established.
For example, should the X-Axis of a table be a resistive value (as read from another
controller), the output of the table could be temperature from an NTC sensor in the range
Y
0
=125ºC to Y
10
= -20ºC. If this table is used as the control source for another function block
