Automationdirect F0-08-ADH-1 User Manual

F0-08ADH-1, 8-CHAnnel
Chapter
Chapter
Chapter
AnAlog Current Input
In This Chapter...
Module Specifications ...............................................................................................4–2
Connecting and Disconnecting the Field Wiring .....................................................4–4
Wiring Diagram .........................................................................................................4–5
Module Operation ..................................................................................................... 4–6
Special V-memory Locations .....................................................................................4–7
Using the Pointer in Your Control Program ............................................................. 4–9
Scale Conversions .................................................................................................... 4–11
Module Resolution ...................................................................................................4–14
Analog Input Ladder Logic Filter ............................................................................4–15
4
4
2
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
Module Specifications
The F0-08ADH-1 Analog Input module offers the following features:
• The DL05 and DL06 will read all eight channels in one scan.
• The removable terminal block simplifies module replacement.
• Analog inputs can be used as process variables for the four (4) PID loops in the DL05 and the eight (8) PID loops in the DL06 CPUs.
• On-board active analog filtering and RISC-like microcontroller provide digital signal processing to maintain precise analog measurements in noisy environments.
• These modules are isolated from the PLC power supply logic side (1800 Volt).
NOTE: The DL05 CPU’s analog feature for this module requires DirectSOFT32 Version 3.0c (or later) and firmware version 5.20 (or later). The DL06 requires DirectSOFT32 version V4.0, build 16 (or later) and firmware version 2.30 (or later). See our website for more information: www.automationdirect.com.
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
The following tables provide the specifications for the F0–08ADH –1 Analog Input Module. Review these specifications to make sure the module meets your application requirements.
Input Specifications
Inputs per module Input Range Resolution Input Type Maximum Continuous Overload Input Impedance Filter Characteristics
PLC Data Format Sample Duration Time
All Channel Update Rate Open Circuit Detection Time Conversion Method Accuracy vs. Temperature Maximum Inaccuracy Linearity Error (End to End) Input Stability and Repeatability Full Scale Calibration Error (incl offset) Offset Calibration Error Maximum Crosstalk at DC, 50 Hz and 60 Hz Recommended Fuse (external) External 24VDC Power Required Base Power Required (5.0 V)
*
Each channel requires 2 words of V-memory irrespective of the format used.
8 0–20 mA 16-bit, 0.305 µA/bit Single Ended (one common) ±31mA 100 ohms, 1/10W, current input Low pass, -3dB @ 60Hz
16-bit, Unsigned Integer, 0–FFFF (binary) or 0–65535 (BCD)
10.2 ms (time to 95% of full step change per channel)
81.6 ms Zero reading within 1s Successive Approximation ±50 PPM/°C Maximum
0.2% of range (including temperature changes) ±10 count maximum; Monotonic with no missing codes ±10 count maximum ±10 count maximum ±10 count maximum ±10 count maximum Littlefuse Series 217, 0.032 A fuse 24VDC ±10% @ 25mA 25mA
*
Operating Temperature Storage Temperature Humidity Environmental air Vibration Shock Field to Logic side Isolation Insulation Resistance
Noise Immunity
Agency Approvals Module Location Field Wiring Weight
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
General Specifications
0 to 55°C (32 to 131°F)
-20 to 70°C (-4 to 158°F) 5 to 95% (non-condensing) No corrosive gases permitted (EN61131-2 pollution degree 1) MIL STD 810C 514.2 MIL STD 810C 516.2 1800VAC applied for 1 second (100% tested) >10M ohms @ 500VDC NEMA ICS3-304; Impulse 1000V @ 1ms pulse;
RFI, (145MHz, 440Mhz 5W @ 15cm); Worst case error during noise disturbance is 0.5% of full scale
UL508; UL60079-15 Zone 2 Any slot in a DL05 or DL06 System Removable Terminal Block 49g (1.7 oz.)
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input

Connecting and Disconnecting the Field Wiring

WARNING: Before removing the analog module or the terminal block on the face of the module, disconnect power to the PLC and all field devices. Failure to disconnect power can result in damage to the PLC and/or field devices.
Wiring Guidelines
Your company may have guidelines for wiring and cable installation. If so, you should check those before you begin the installation. Here are some general things to consider:
• Use the shortest wiring route whenever possible.
• Use shielded wiring and ground the shield at the transmitter source. Do not ground the shield at both the module and the source.
• Do not run the signal wiring next to large motors, high current switches, or transformers. This may cause noise problems.
• Route the wiring through an approved cable housing to minimize the risk of accidental damage. Check local and national codes to choose the correct method for your application.
The F0–08ADH–1 does not supply power to field devices. You will need to power transmitters separately from the PLC.
To remove the terminal block, disconnect power to the PLC and the field devices. Pull the terminal block firmly until the connector separates from the module.
You can remove the analog module from the PLC by folding out the retaining tabs at the top and bottom of the module. As the retaining tabs pivot upward and outward, the module’s connector is lifted out of the PLC socket. Once the connector is free, you can lift the module out of its slot.
NOTE: The F0–08ADH–1 analog module cannot sense the loss of analog input signals in 0–20 mA loops.
Terminal Block Specifications
Number of Positions Re-Order Number Pitch
Wire Range
Screwdriver Size (Slotted) Screw Size Screw Torque
13 D0-ACC-4
0.2 inch (5.08 mm) 28–16 AWG Solid or Stranded Conductor;
Wire strip length 5/16” (7–8 mm)
0.4T x 2.5W mm (part number DN-SS1) M2.5 size
4.5 inch-pounds (0.52 N·m)
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
0V

Wiring Diagram

Use the following diagram to connect the field wiring. If necessary, the F0–08ADH–1 terminal block can be removed to make removal of the module possible without disturbing field wiring.
2-wire 4–20mA
Transmitter
2-wire 4–20mA
Transmitter
4-wire 4–20mA
Transmitter
3-wire 4–20mA
Transmitter
SHIELD CONNECTED TO SIGNAL SOURCE COMMON. SEE NOTE 2.
Note 1: A Littelfuse Series 217, 0.032A fast-acting fuse is recommended for all 4-20mA current loops. Note 2: Do not connect both ends of shield.
Current Loop Transmitter Impedance
Manufacturers of transmitters and transducers specify a wide variety of power sources for their products. Follow the manufacturer’s recommendations.
In some cases, manufacturers specify a minimum loop or load resistance that must be used with the transmitter. The F0-08ADH-1 provides 100 ohm resistance for each channel. If your transmitter requires a load resistance below 100 ohms, you do not have to make any changes. However, if your transmitter requires a load resistance higher than 100 ohms, you need to add a resistor in series with the module.
Consider the following example for a transmitter being operated from a 30VDC supply with a recommended load resistance of 750 ohms. Since the module has a 100 ohm resistor, you need to add an additional resistor.
R = Tr–Mr R = Resistor to add
R = 750–100 Tr = Transmitter requirement
R M 650 Mr = Module resistance (internal 100 ohms)
4-20mA Transmitter
4-20mA Transmitter
4-20mA Transmitter
Shield, Ch. 5
+
4-20mA Transmitter
Shield, Ch. 1
SEE NOTE 1.
Shield, Ch. 3
Shield, Ch. 8
.032A
AC or DC
24VDC
Power Supply
CH1
CH3
COM
CH5
CH8
COM
COM
+24VDC
0VDC
Internal Module CircuitryTypical User Wiring
0V
CH1 ADC
CH2 ADC
CH3 ADC
CH4 ADC
CH5 ADC
CH6 ADC
CH7 ADC
CH8 ADC
ISOLATED ANALOG CIRCUIT POWER
IN
F0-08ADH-1
ANALOG
0–20mA
CH1
CH2
CH3
CH4
COM
CH5
CH6
CH7
CH8
COM
COM
+24V
0V
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
DC Supply
+30V
0V
Two-wire Transmitter
+–
R
Module Channel 1
CH1
COM
125 ohms
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input

Module Operation

Channel Scanning Sequence
The DL05 and DL06 will read all eight channels of input data during each scan. Each CPU supports special V-memory locations that are used to manage the data transfer. This is discussed in more detail beginning in the section on “Special V-memory Locations”.
Scan
Read Inputs
Execute Application Program
Read the data
Store data
Write to Outputs
Scan N
Scan N+1
Scan N+2
Scan N+3
Scan N+4
DL05/DL06 PLC
Ch 1, 2, 3, 4, 5, 6, 7, 8
Ch 1, 2, 3, 4, 5, 6, 7, 8
Ch 1, 2, 3, 4, 5, 6, 7, 8
Ch 1, 2, 3, 4, 5, 6, 7, 8
Ch 1, 2, 3, 4, 5, 6, 7, 8
Analog Module Updates
Even though the channel updates to the CPUs are synchronous with the CPU scan, the module asynchronously monitors the analog transmitter signals and converts each signal into a 16-bit binary representation. This enables the module to continuously provide accurate measurements without slowing down the discrete control logic in the RLL program.
The module takes approximately 10.2 milliseconds to sense 95% of the change in the analog signal per channel. It takes approximately 81.6 ms to sample all channels.
NOTE: If you are comparing other manufacturers’ update times (step responses) with ours, please be aware that some manufacturers refer to the time it takes to convert the analog signal to a digital value. Our analog to digital conversion takes only a few microseconds. It is the settling time of the filter that is critical in determining the full update time. Our update time specification includes the filter settling time.
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input

Special V-memory Locations

Formatting the Analog Module Data
The DL05 and DL06 PLCs have special V-memory locations assigned to their respective option slots. These V-memory locations allow you to:
• Specify the data format (binary or BCD)
• Specify the number of channels to scan (up to 8 channels for the F0–08ADH–1)
• Specify the V-memory locations to store the input data
DL05 Data Formatting
The table below shows the special V-memory locations used by the DL05 PLC for the F0–08ADH–1.
Analog Input Module
DL05 Special V-memory Locations
Data Type and Number of Channels V7700 Storage Pointer V7701
Setup Data Type and Number of Active Channels
Special V-memory location 7700 is used to set the data format to either BCD or binary and to set the number of channels that will be active.
For example, assume the F0–08ADH–1 is installed in the option slot. Loading a constant of 800 into V7700 sets 8 channels active and causes the input data value to be read as a BCD number.
With the F0–08ADH–1 in the option slot, loading a constant of 8800 into V7700 sets 8 channels active, and the input data value is read as a binary number.
V7700 BCD setup
MSB LSB
101112131
101112131
78965432
78965432
5
4
V7700 binary setup
MSB LSB
5
4
11
11
0
0
Storage Pointer Setup
V7701 is a system V-memory location used as a pointer to a user V-memory location where the analog input data is stored. The V-memory location loaded into V7701 is an octal number identifying the first user V-memory location for reading the analog input data. This V-memory location is user selectable. For example, loading O2000 causes the pointer to write Ch 1’s data value to V2000 – 2001, Ch 2’s data value to V2002 – 2003, Ch 3’s data value to V2004 – 2005, Ch 4’s data value to V2006 – 2007, Ch 5’s data value to V2010 – 2011, Ch 6’s data value to V2012 – 2013, Ch 7’s data value to V2014 – 2015, and Ch 8’s data value to V2016 – 2017.
You will find an example program that loads appropriate values to V7700 and V7701 on page 4–9.
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
5
4
V700 BCD setup
DL06 Data Formatting
Special V-memory locations are assigned to the four option slots of the DL06 PLC. The table below shows these V-memory locations which can be used to setup the F0–08ADH–1.
Analog Input Module
DL06 Special V-memory Locations
Slot No. 1 2 3 4 Data Type and Number of Channels V700 V710 V720 V730 Storage Pointer V701 V711 V721 V731
Setup Data Type and Number of Active Channels
V-memory locations 700, 710, 720, and 730 are used to set the data format to either BCD or binary and to set the number of channels that will be active.
For example, assume the F0–08ADH–1 is installed in slot
1. Loading a constant of 800 into V700 sets 8 channels active and causes the input data value to be read as a BCD number.
With the F0–08ADH–1 in slot 1, loading a constant of 8800 into V700 sets 8 channels active, and the input data value is read as a binary number.
Storage Pointer Setup
V-memory locations 701, 711, 721 and 731 are special locations used as storage pointers. A V-memory address is loaded into this location as an octal number identifying the first user V-memory location for the analog input data. This V-memory location is user selectable. For example, loading O2000 causes the pointer to write Ch 1’s data value to V2000 – 2001, Ch 2’s data value to V2002 – 2003, Ch 3’s data value to V2004 – 2005, Ch 4’s data value to V2006 – 2007, Ch 5’s data value to V2010 – 2011, Ch 6’s data value to V2012 – 2013, Ch 7’s data value to V2014 – 2015, and Ch 8’s data value to V2016 – 2017.
You will find an example program that loads appropriate values to V700 and V701 beginning on page 4–10.
MSB LSB
101112131
101112131
78965432
78965432
5
4
V700 binary setup
MSB LSB
11
11
0
0
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input

Using the Pointer in Your Control Program

DL05 Pointer Method Using Conventional Ladder Logic
NOTE: The proper use of the DL05 pointer requires that the V-memory address be written to the special memory location on the first scan only. Use the SP0 bit as a permissive contact when using the code shown below.
The example program below shows how to setup the special V-memory locations. This rung can be placed anywhere in the ladder program or in the initial stage if you are using stage programming instructions.
This is all that is required to read the analog input data into V-memory locations. Once the data is in V-memory you can perform math on the data, compare the data against preset values, and so forth. V2000 is used in the example but you can use any user V-memory location.
SP0
LD K800
Loads a constant that specifies the number of channels to scan and the data format. The upper byte selects the data format (i.e. 0=BCD, 8=Binary) and the number of channels (up to 8 for the F0-08ADH-1).
- or -
LD K8800
OUT V7700
LDA O2000
OUT V7701
The binary format is used for displaying data on some operator interface units. The DL05 PLCs support binary math functions.
Special V-memory location assigned to the option slot contains the data format and the number of channels to scan.
This loads an octal value for the first V-memory location that will be used to store the incoming data. For example, the O2000 entered here would designate the following addresses:
Ch1 – V2000-2001, Ch2 – V2002-V2003, Ch3 – V2004-V2005, Ch 4 – V2006-2007 Ch 5 – V2010-2011, Ch 6 – V2012-V2013, Ch 7 – V2014-V2015, Ch 8 – V2016-V2017.
The octal address (O2000) is stored here. V7701 is assigned to the option slot and acts as a pointer, which means the CPU will use the octal value in this location to determine exaclty where to store the incoming data.
DL05 Pointer Method Using the IBox Instruction Available in DirectSOFT5
The following logic accomplishes the same thing as the previous ladder example, but it uses the IBox instruction ANLGIN.
Analog Input Module Pointer Setup
ANLGIN IB-460
No permissive contact or input logic is used with this instruction. This instruction operates on the first scan only.
Base # (K0 - Local) Slot # Number of Input Channels Input Data Format (0 - BCD 1 - BIN) Input Data Address
K0 K1 K8 K0
V2000
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
DL06 Pointer Method Using Conventional Ladder Logic
NOTE: The proper use of the DL06 pointer requires that the V-memory address be written to the special memory location on the first scan only. Use the SP0 bit as a permissive contact when using the code shown below.
Use the special V-memory table below as a guide to setup the storage pointer in the following example for the DL06. Slot 1 is the left most option slot.
Analog Input Module
DL06 Special V-memory Locations
1 2 3 4
No. of Channels V700 V710 V720 V730 Input Pointer V701 V711 V721 V731
The F0–08ADH–1 can be installed in any available DL06 option slot. The ladder diagram below shows how to set up these locations with the module installed in slot 1 of the DL06. Use the above table to determine the pointer values if locating the module in any of the other slot locations. Place this rung anywhere in the ladder program or in the initial stage if you are using stage programming instructions.
This logic is all that is required to read the analog input data into V-memory locations. Once the data is in V-memory you can perform mathematical calculations with the data, compare the data against preset values, and so forth. In the example, V2000 is used, but you can use any user V-memory location.
4–10
SP0
LD K800
Loads a constant that specifies the number of channels to scan and the data format. The upper byte selects the data format (i.e. 0=BCD, 8=Binary) and the number of channels (up to 8 for the F0-08ADH-1).
- or -
LD
K8800
OUT V700
LDA O2000
OUT V701
The binary format is used for displaying data on some operator interface units and the DL06 display. The DL06 PLCs support binary math functions.
Special V-memory location assigned to the first option slot contains the data format and the number of channels to scan.
This loads an octal value for the first V-memory location that will be used to store the incoming data. For example, the O2000 entered here would designate the following addresses:
Ch1 – V2000-2001, Ch2 – V2002-V2003, Ch3 – V2004-V2005, Ch 4 – V2006-2007 Ch 5 – V2010-2011, Ch 6 – V2012-V2013, Ch 7 – V2014-V2015, Ch 8 – V2016-V2017.
The octal address (O2000) is stored here. V701 is assigned to the first option slot and acts as a pointer, which means the CPU will use the octal value in this location to determine exaclty where to store the incoming data.
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
H – L
DL06 Pointer Method Using the IBox Instruction Available in DirectSOFT6
The following logic accomplishes the same thing as the previous ladder example, but it uses the IBox instruction ANLGIN.
Scale
No permissive contact or input logic is used with this instruction. This instruction operates on the first scan only.
Conversions
Scaling the Input Data
Many applications call for measurements in engineering units, which can be more meaningful than raw data. Convert to engineering units using the formula shown to the right.
You may have to make adjustments to the formula depending on the scale you choose for the engineering units.
For example, if you wanted to measure pressure (PSI) from 0.0 to 99.9 then you would have to multiply the analog value by 10 in order to imply a decimal place when you view the value with the programming software or a handheld programmer. Notice how the calculations differ when you use the multiplier.
Analog Value of 32375, slightly less than half scale, should yield 49.4 PSI.
Analog Input Module Pointer Setup
ANLGIN IB-460
Base # (K0 - Local) Slot # Number of Input Channels Input Data Format (0 - BCD 1 - BIN) Input Data Address
Units = A
H = High limit of the engineering
L = Low limit of the engineering
A = Analog value (0 – 65535)
65535
unit range
unit range
K0 K1 K8 K0
V2000
+ L
Example without multiplier Example with multiplier
Units = A
Units=
32375
Units= 49
H – L
65535
+ L
100 – 0
65535
+ 0
Units=10 x A
Units=323750
Units=494
H – L
65535
100 – 0
65535
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
+ L
+ 0
4–11
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
The Conversion Program in Standard Ladder Logic
The following example shows how you would write the program to perform the engineering unit conversion. This example assumes you have BCD data loaded into the appropriate V-memory locations using instructions that apply for the model of CPU you are using.
_First Scan
SP0
LDD K100
Loads the constant 100 to the accumulator.
_On
SP1
OUTD V3000
LDD K65535
OUTD V3002
LDD V2000
MULD V3000
DIVD V3002
OUTD V2100
V2000/2001
32375
Copies the constant 100 from the accumulator to the memory location V3000 and V3001.
Loads the constant 65535 to the accumulator.
Copies the content (65535) from the accumulator to the memory location V3002 and V3003.
Loads data from V2000 and V2001.
Multiplies the accumulator value by 100 (previously loaded into V3000 and V3001).
Divides the accumulator value by 65535 (previously loaded into V3002 and V3003).
Copies the content of the accumulator to the memory location V2100 and V2101.
V2100/2101
49
4–12
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Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
A
A
Analog and Digital Value Conversions
Sometimes it is useful to convert between the signal levels and the digital values. This is especially helpful during machine start-up or troubleshooting. The following table provides formulas to make this conversion easier.
Range If you know the digital value If you know the analog signal level
20
0 to 20mA
=
65535
.
D
For example, if you have measured the signal as 10mA, you can use the formula to determine the digital value that should be stored in the V-memory location that contains the data.
65535
20
65535
20
65535
20
.
D =
D =
D =
D = 32767
.
A
.
10mA
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Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
0 – 20mA
065535
e

Module Resolution

Analog Data Bits
Two 16-bit words are reserved for the analog data whether you are using BCD or binary data formatting. The 16 bits in the low word represent the analog data in binary format.
BCD Example
MSB LSB
MSB LSB
V2000V2001
0
132
Binary Example
MSB LSB
1 5
101112131
4
7896540132
0
0
132
MSB LSB
5
= data bits
101112131
4
132
V2000V2001
78965432
132
0
0
132
0
11
Resolution Details
Since the module has 16-bit resolution, the analog signal is converted into 65,536 counts ranging from 0 - 65,535 (216). A 0mA signal would be 0 and a 20mA signal would be 65535. This is equivalent to a binary value of 0000 0000 0000 0000 to 1111 1111 1111 1111, or 000 to FFFF hexadecimal.
Each count can also be expressed in terms of the signal level by using the following equation:
20mA
0mA
Resolution =
H = high limit of the signal rang
L = low limit of the signal range
H – L
65535
4–14
The following table shows the smallest detectable signal change that will result in one LSB change in the data value for each increment of the signal change.
mA Range
0 to 20mA 20mA 65535 0.3052µA
Signal Span
(H – L)
Divide By
Smallest Detectable
Change
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
SP1

Analog Input Ladder Logic Filter

PID Loops / Filtering
Please refer to the “PID Loop Operation” chapter in the DL06 or DL05 User Manual for information on the built-in PV filter (DL05/06) and the ladder logic filter (DL06 only) shown below. A filter must be used to smooth the analog input value when auto tuning PID loops to prevent giving a false indication of loop characteristics.
Smoothing the Input Signal (DL06 only)
The filter logic can also be used in the same way to smooth the analog input signal to help stabilize PID loop operation or to stabilize the analog input signal value for use with an operator interface display, etc.
WARNING: The built-in and logic filters are not intended to smooth or filter noise generated by improper field device wiring or grounding. Small amounts of electrical noise can cause the input signal to bounce considerably. Proper field device wiring and grounding must be done before attempting to use the filters to smooth the analog input signal.
Binary Data Format Filter Using Ladder Logic
LDD V2000
BTOR
Loads the analog signal, which is in binary format and has been loaded from V–memory location V2000 – 2001, into the accumulator. Contact SP1 is always on.
Converts the binary value in the accumulator to a real number.
Subtracts the real number stored in location
SUBR V1400
MULR R0.2
ADDR V1400
OUTD V1400
RTOB
OUT V2100
V1400 from the real number in the accumulator, and stores the result in the accumulator. V1400 is the designated workspace in this example.
Multiplies the real number in the accumulator by
0.2 (the filter factor), and stores the result in the accumulator. This is the filtered value. The filter range is 0.1 to 0.9. Smaller filter factors increase filtering. (1.0 eliminates filtering.)
Adds the real number stored in location V1400 to the real number filtered value in the accumulator, and stores the result in the accumulator.
Copies the value in the accumulator to location V1400.
Converts the real number in the accumulator to a binary value, and stores the result in the accumulator.
Loads the binary number filtered value from the accumulator into location V2100 to use in your application or PID loop.
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Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
SP1
NOTE: Be careful not to do a multiple number conversion on a value. For example, if you are using the pointer method in BCD format to get the analog value, it must be converted to binary (BIN) as shown below. If you are using the pointer method in Binary format, the conversion to binary (BIN) instruction is not needed.
BCD Data Format Filter Using Ladder Logic
LDD V2000
BIN
BTOR
SUBR V1400
MULR R0.2
ADDR V1400
OUTD V1400
RTOB
Loads the analog signal, which is in BCD format and has been loaded from V–memory location V2000 – 2001, into the accumulator. Contact SP1 is always on.
Converts the BCD value in the accumulator to binary.
Converts the binary value in the accumulator to a real number.
Subtracts the real number stored in location V1400 from the real number in the accumulator, and stores the result in the accumulator. V1400 is the designated workspace in this example.
Multiplies the real number in the accumulator by
0.2 (the filter factor), and stores the result in the accumulator. This is the filtered value. The filter range is 0.1 to 0.9. Smaller filter factors increase filtering. (1.0 eliminates filtering.)
Adds the real number stored in location V1400 to the real number filtered value in the accumulator, and stores the result in the accumulator.
Copies the value in the accumulator to location V1400.
Converts the real number in the accumulator to a binary value, and stores the result in the accumulator.
4–16
Converts the binary value in the accumulator
BCD
OUTD V2100
to a BCD number. Note: The BCD instruction is not needed to PID loop PV (loop PV is a binary number).
Loads the BCD number filtered value from the accumulator into location V2100 to use in your application or PID loop.
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Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
Load V2020 with the maximum engineering value (1000 in this example). Load
Example Code to Scale a 4–20 mA Signal to 0–1000 BCD
(For applications where the field transmitter sends a 4–20 mA signal to the analog input card.)
This example will scale the first input, a double word BCD value located at V2000 and V2001, as a 4–20 mA input signal from 0–1000. Because the input card ranges from 0–20 mA instead of 4–20 mA, an offset value must be used to deal with the 0–4 mA values. Any value below a 4mA (13107) value is forced to a 4mA (13107) value.
V2022 with the maximum 16-bit value after the 4mA value (13107) is subtracted.
SP1
LDD K1000
OUTD V2020
Determine if the incoming value is below 4mA, or 13107 counts.
V2001 V2000K1
=
V2001
K2
If the incoming value is below 4mA (13107 count) then load the minimum count value of 13107 into the accumulator.
C0
If the incoming value is between 4mA and 20mA then load the incoming count value into the accumulator.
C0
Scale the incoming raw count of 13107 to 65535 to a value between 0 and 1000. Output the value in V3000.
SP1
LDD K52428
OUTD V2022
K3107
C0
OUT
LDD K13107
LDD V2000
SUBD K13107
MULD V2020
DIVD V2022
OUT V3000
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
4–17
Chapter 4: F0-08ADH-1, 8-Channel Analog Current Input
Load V2020 with the maximum engineering value (1000 or 3E8h in this example). Load
Example Code to Scale a 4–20 mA Signal to 0–1000 Binary
(For applications where the field transmitter sends a 4–20 mA signal to the analog input card.)
This example will scale the first input, a binary/decimal value located at V2000 (the CPU reserves two words for each channel so V2000 and V2001 are reserved), as a 4–20 mA input signal from 0–1000. Because the input card ranges from 0–20 mA instead of 4–20 mA, an offset value must be used to deal with the 0–4 mA values. Any value below a 4mA (13107 or 3333h) value is forced to a 4mA (13107 or 3333h) value.
V2022 with the maximum 16-bit value after the 4mA value (13107 or 3333h) is subtracted.
SP1
LDD K1000
If the incoming value is below 4mA (13107 or 3333h) then load the minimum count value of 13107 (3333h) into the accumulator.
V2000 K3333
<
If the incoming value is between 4mA and 20mA then load the incoming count value into the accumulator.
V2000 K3333
Scale the incoming raw count of 13107 (3333h) to 65535 (FFFFh) to a value between 0 and 1000 (3E8h). Output the value in V3000 as a binary/decimal number.
SP1
BIN
OUTD V2020
LDD K52428
BIN
OUTD V2022
LDD K3333
LDD V2000
SUBB K3333
MULB V2020
DIVB V2022
4–18
DL05/06 Option Modules User Manual; 7th Ed. Rev. E
OUT V3000
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