Horner APG XLt OCS HE-XT103-10 User Manual
Page 3
MAN0871-02
21
AUGUST
2007
PAGE
3
Specifications
/
Installation
XLT103-10
5 Analog
Conditioning
5.1 Filter
Filter Constant sets the level of digital filtering according to the following
chart.
Digital Filtering
.
The illustration above demonstrates the effect of digital
filtering (set with Filter Constant) on module response to a
temperature change.
It is recommended that the filter constant for the HE-XT103-10 be set to a
value of 7. This will minimize noise and jitter, improve effective resolution,
and provide adequate speed for most temperature monitor and control
applications.
5.2 Thermistor
Linearization
Thermistors are measured using a half-bridge circuit that exhibits variable resolution
and the associated increased measurement range.
Temperature, degrees C
Resolution, degrees C
-55 1.05
-35 0.36
-15 0.17
5 0.11
25 0.1
45 0.13
65 0.22
85 0.30
105 0.55
125 0.85
145 1.35
Best resolution is at 25°C, 77°F. With a constant 0.1°C resolution circuit, the
measurement range would only extend from –26°C to +76°C.
Linearization must be performed by the user in the ladder application code, using 26
internal %R registers per channel. The example below uses %R1-26 to linearize one
channel - %AI1. Linearization consists of the following example steps.
1. Load the desired linearization coefficients into a table on First Scan using a Move
Constant Data block.
Registers (Real)
Degrees C
Degrees F
R0011 -1.94454e-028
-3.50017e-028
R0013 2.40268e-023
4.32483e-023
R0015 -1.24101e-018
-2.23381e-018
R0017 3.46655e-014
6.23979e-014
R0019 -5.69403e-010
-1.02493e-009
R0021 5.62368e-006
1.01226e-005
R0023 -0.0353121
-0.0635617
R0025 163.878
326.981
2. Load %AI0001 into %R0001 as a Real.
3. Perform the Real Math Expression
%R3 = (((%R11*%R1+%R13)*%R1+%R15)*%R1+%R17)
4. Perform the Real Math Expression %R5 =
(((%R3*%R1+%R19)*%R1+%R21)*%R1+%R23)*%R1+%R25
5. Load %R0005 result into another register such as %R0007 to save the temperature
value.
Steps 2 though 5 can be on a single rung.
The expression rung may be copied, substituting %AI0002 and %R00011 for %AI0001 and
%R0007, and used to linearize the second channel. Contact Horner APG for an example file
containing the above program.
5.3 Thermistor
types
The HE-XT103-10 with the given example ladder code supports Kele Engineering Precon
Type III, 10 KΩ thermistors. It also directly supports the following 10 KΩ (Beta=3574)
thermistors from Yellow Springs Instruments (YSI).
44006 46006
44106 46031
44406 46041
44031 44907
45006 44908
6 I/O
Register
Map
Registers
Description
%I1 to %I12
Digital Inputs
%I32 Output
Fault
%I25 to %I31
Reserved
%Q1 to %Q16
Digital Outputs
%Q17
Clear HSC1 accumulator to 0
%Q18
Totalizer: Clear HSC2
Quadrature 1-2: Accumulator 1
Reset to max – 1
%Q19
Clear HSC3 Accumulator to 0
%Q20
Totalizer: Clear HSC4
Quadrature 3-4: Accumulator 3
Reset to max – 1
%Q21 to %Q32
Reserved
%AI1 to %AI4
Analog inputs
%AI5, %AI6
HSC1 Accumulator
%AI7, %AI8
HSC2 Accumulator
%AI9, %AI10
HSC3 Accumulator
%AI11, %AI12
HSC4 Accumulator
%AQ9 to %AQ14
Analog outputs
%AQ1, %AQ2
PWM1 Duty Cycle
%AQ3, %AQ4
PWM2 Duty Cycle
%AQ5, %AQ6
PWM Prescale
%AQ7, %AQ8
PWM Period
Note:
Not all XLT units contain the I/O listed in this table.
Registers
PWM
HSC
Stepper
%AQ1
Start
Frequency
%AQ2
PWM1 Duty
Cycle
(32 bit)
HSC1
Preset
Value
Run
Frequency
%AQ3
%AQ4
PWM2 Duty
Cycle
(32 bit)
HSC2
Preset
Value
Accel Count
(32 bit)
%AQ5
%AQ6
PWM Prescale
(32 bit)
Run Count
(32 bit)
%AQ7
%AQ8
PWM Period
(32 bit)
Decel Count
(32 bit)
%Q1
Run
%I30 Ready/Done
%I31
Error
60
20
100
40
80
20
0
10
100
90
80
70
60
50
40
30
Scans
0
1
2
3
4
5
6
0
7
%
C
o
m
p
let
e
[
]
Filter
Constant