Series 90™ Micro Analog I/O Through CALEX Signal Conditioners

Transkrypt

Application
Bulletin
No: H-06-96-02
To: 1, 2, 3, 4/5
Analog I/O is useful in a broad range of applications for such things as pressure and level sensing,
positioning, and temperature control. The Series 90 Micro in conjunction with CALEX signal conditioning
units provides a cost effective solution. Analog channels may be added on a per channel basis which
allow customers to tailor their system at an incremental cost. CALEX signal conditioning units require only
1 discrete input (for Analog inputs) or 1 discrete output (for Analog outputs), with setup for use only
required in the configuration of the PLC. Currently available solutions are 11 bit resolution equivalent.
Installation is made easy through DIN rail mounting and Phoenix European style wiring terminals. CALEX
signal conditioners are available in Current In, Current Out, Voltage In, Voltage Out, and J type
Thermocouple units. Space requirements are approximately 1.65” H(42)x1.06”W(27)x3.78”L(96) and
weighing only 3oz(85 grams).
APPLICATION :
A user desires to use one input channel of analog and one output channel of analog for controlling flow
rate. The analog input channel is used to determine fluid level and the analog output channel for
controlling valve positioning to vary flow rate into a tank. Additionally the user would like to scale the
output so that a 1-to-1 relationship exists between the user value entered and the frequency sent out to
the Frequency to Analog converter.
The Series 90 Micro PWM and PT frequencies are varied by entering a value into the AQ2 and AQ123
registers respectively. The value entered does not give a one-to-one translation in frequency for the high
speed output. An inverse relationship exists for the actual frequency that is output where the lower the
value placed in the AQ2 register the higher the frequency sent out. The PWM output for example will be
set to the maximum frequency of 2khz for a decimal value of 614 written into the AQ2 register and 20hz
for a decimal value of 61439.
GE Fanuc Automation North America, Inc.
Page 2 of 5
H-06-96-02
A n a lo g
O u tp u t
+
24V D C
-
I1
I2
I3
I4
COM 1
I5
I6
I7
I8
COM 2
2 4 VD C O U T
IN P U T
I9
I1 0
I1 1
I1 2
COM 3 COM 3
I5
I6
I8 C O M 4 C O M 4
I7
P WR
OK
GE FANU C
1
S e r ie s 9 0 M ic r o
IN P U T
RU N
IN P U T
A n a lo g S ig n a l
C o n d itio n e r
In p u t
9
2
3
4
5
6
7
10
11
12
13
14
15
16
8
7
8
O U TPU T
OUTPUT
9
10
11
12
PR O G R A M M AB LE CO NTR O LLER
~
OUTPUT
8 5 -2 6 5 V A C
L
+
H
1 2 02/ 4 0
VAC
H
N
~
Q1
V
GN D
CO M 1 VC
Q2
Q3
L
O
A
D
L
O
A
D
Q4
Q5 COM 2
Q6
L
O
A
D
L
O
A
D
L
O
A
D
A C or D C
P o w e r S o u rc e
or
24 VD C
24V D C
COM 3
Q7
COM 4
L
O
A
D
A C or D C
AC or DC
Q8
COM 5 Q9
L
O
A
D
24VDC
-
+
3
K
L
O
A
D
A C or D C
A C or D C
P o w e r S o u rc e P o w e r S o u rc e
-
A n a lo g
In p u t
C O M 6 Q 10
3 K p u lld o w n
L
O
A
D
Q 11
Q 12
L
O
A
D
L
O
A
D
C O M 7C O M 7
A C or D C
A n a lo g S ig n a l
C o n d itio n e r
O u tp u t
Page 3 of 5
H-06-96-02
SOLUTION:
The proposed solution requires the following:
§ Logic Master Series 90 Micro or Series 90/30/20 Logic Master (either at Rel 6.0 or greater)
§ Double Integer division and multiplication math functions in application code
§ DC output equipped Series 90 Micro
§ CALEX signal conditioning input Unit
§ CALEX signal conditioning output Unit
EXAMPLE The CALEX 8507 input signal conditioner produces a 0 to 5khz wave for a 0 to 10 volt input.
The frequency varies proportionally to the voltage applied from the field side of the unit. A frequency seen
by the Series 90 Micro of 1.25khz would correspond to a sensor voltage input of 2.5 VDC.
To setup for the CALEX signal conditioning input units, invoke the LM90 configuration package and select
the I/O option. The signal conditioning input unit sends out a frequency that is proportional to the voltage
or current applied from the field side. The frequency is feed into one of the Type A HSC inputs on the
Series 90 Micro. To configure the Series 90 Micro, set the HSC type to A, enable counts, and set time
base to the number of counts desired (ex. 1000ms timebase will display 2000 count for a 2Khz wave sent
out by the signal conditioner). A way to speed up the effective throughput of the CALEX input unit, is to
decrease the counts per timebase and scaled according to user needs in the ladder logic (ex. A 500ms
timebase will display 1000 counts for a 2Khz wave which can be scaled through a multiplication function in
ladder to 2000 counts). The corresponding frequency can be viewed in the counts per timebase register
(for the above example HSC 2 counts per timebase register is AI03). It should be noted that the TYPE A
counter setup requires 2 inputs for each counter. If the second input required for a TYPE A counter is not
used for strobing the counter, it is still available as an input. This means that the signal conditioning input
only requires one input per analog channel in. Additionally, due to hardware restraints when the high
speed output function is used (PWM or PT), channel one may not be used as a high speed counter input.
This makes the maximum number of AI set to three when PWM or PT is required in TYPE A counter
mode.
EXAMPLE The CALEX 8510 output signal conditioner produces a 0 to 5 VDC output for a 0 to 2khz input
from the Series 90 Micro. The voltage output varies proportionally to the applied frequency. A frequency of
1Khz would result in an output voltage of 2.5VDC. It should be noted that the Series 90 Micro does not
allow frequencies of less than 19hz to be produced since the largest supported value for the AQ2 register
is hex FFFF. In addition the frequency that may be output is in increments of 3hz best case but varies
between 3 and 4hz due to rounding effects of the equation.
The setup for the signal conditioning output is similar to the input but values need to be written to AQ2 and
AQ3 registers to set up frequency and duty cycle respectively. From the LM90 Configuration package
select the I/O configuration, select TYPE A counter option, disable Counter 1, and Enable PWM output.
From the LM90 Programmer package set the value of the AQ3 register to 200 decimal (this value
produces the proper duty cycle over the full frequency range), and set the AQ2 register to the required
value to produce the desired frequency according to the equation [Frequency = 9.84mhz / 8*(AQ2+1)].
The above frequency output equation is re-written in terms of AQ2 as follows: [AQ2 = (9.84mhz
/8*Frequency) -1] which represents the value that needs to be written into the AQ2 register to produce the
desired frequency. The attached application code solves the above equation and writes the value into the
AQ2 register. Due to firmware constraints the lowest frequency that can be obtained is 19hz. Value less
than 19 exceed the maximum value allowed for the AQ2 register. The application code will set the
frequency to 100% duty cycle (constantly on “1”) for a value of less that 19 written into the AQ2 register.
BENEFITS:
§ Analog available on a per channel basis
§ Cost effective solution
§ Ease of ramping output through application code with a 1-to-1 relationship for scaling
§ Readability of desired output frequency without doing conversion prior to entering into AQ2 register
Steve Hogge
Series 90 Product Manager
Page 4 of 5
REFERENCE NICKNAME
%S0007
ALW_ON
%R0015
CONST
%R0017
OUT_HZ
%R0021
ROUND1
%R0023
ROUND2
%R0019
SCALE1
H-06-96-02
REFERENCE DESCRIPTION
9.84 MHz / 8
PWM or PT desired output
Round up by adding 0.5
Divide by 10 to finish round up
9.84MHz/8*Frequency
|[ START OF LD PROGRAM CALEX1
]
|
|[
VARIABLE DECLARATIONS
]
|
|[
BLOCK DECLARATIONS
]
|
|[
START OF PROGRAM LOGIC
]
| << RUNG 4 STEP #0001 >>
|ALW_ON
|%S0007
+-----+
+--] [-----------+ DIV_+|
| DINT|
|
|
|
|
CONST | | SCALE1
|
%R0015 -+I1 Q+-%R0019
|
+0012300000
|
| +0000098400
|
OUT_HZ | |
|
%R0017 -+I2
|
|
+0000000125
+-----+
| << RUNG 5 STEP #0003 >>
|ALW_ON
|%S0007
+-----+
+-----+
+--] [-----------+ ADD_+---------------------------------+ DIV_+|
|
| DINT|
|
|
|
|
|
|
SCALE1 | | ROUND1
ROUND1 |
| ROUND2
|
%R0019 -+I1 Q+-%R0021
%R0021 -+I1 Q+-%R0023
| +0000098400
|
| +0000098405
+0000098405
|
|+0000009840
|
CONST -+I2
|
CONST -+I2
|
|
+0000000005 +-----+
+0000000010 +-----+
| DINT|
Page 5 of 5
| << RUNG 6 STEP #0006 >>
|ALW_ON
|%S0007
+-----+
+--] [-----------+ SUB_+|
| DINT|
|
|
|
|
ROUND2 | | SUB1
|
%R0023 -+I1 Q+-%R0025
| +0000009840
|
| +0000009839
|
CONST -+I2
|
|
+0000000001 +-----+
|
| << RUNG 7 STEP #0008 >>
|ALW_ON
|%S0007
+-----+
+--] [-----------+ LE_ |
|
| DINT|
|
|
|
|
SUB1
|
|
+-----+
|
%R0025 -+I1 Q+---------+MOVE_+|
+0000009839
|
|
| INT |
|
|
|
|
|
|
MAX_ALW | | SUB1 |
| PWM_PT
|
%R0027 -+I2
| %R0025 -+IN Q+-%AQ002
|
+0000065535
+-----+ +09839
| LEN | +09839
|
|00001|
|
|
|
|
+-----+
| << RUNG 8 STEP #0011 >>
|ALW_ON
|%S0007
+-----+
+--] [-----------+ GT_ |
|
| DINT|
|
|
|
|
SUB1
|
|
+-----+
|
%R0025 -+I1 Q+---------+MOVE_+|
+0000009839
|
|
| INT |
|
|
|
|
|
|
MAX_ALW | |
|
| PWM_PT
|
%R0027 -+I2
| CONST -+IN Q+-%AQ002
|
+0000065535
+-----+ +00000 | LEN | +09839
|
|00001|
|
|
|
|
+-----+
|[
END OF PROGRAM LOGIC
]
H-06-96-02

Series 90™ Micro Analog I/O Through CALEX Signal Conditioners

Transkrypt

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