PLCs and Vision Appliance
Functions
IPD Technical Conference
February 19th 2008
PLC Types
 ModBus PLC
 EtherNet/IP
 AB Control Logix
 GE Fanuc SNP / SRTP
 Melsec PLC
 Omron C
 Motoman MRC / XRC
Modbus PLC
 Modbus connection consists of 2 parties
 Modbus Slave : Offers register storage which it
 accesses locally
 makes available to one or more masters
 Modbus Master
 accesses one slave device register set
ModBus PLC
 VA can be added as
 Modbus Master
 Modbus Slave
VA as Modbus Master
 TCP/IP
 Can be a master of multiple slave devices
 Add a PLC Destination for each IP Address
 RS232
 Only one PLC slave per serial port
VA as Modbus Slave
 Multiple Modbus masters can connect to one VA
Modbus Slave.
 2 VAs can communicate with each other;
 One VA as Master, connected to the other VA as a Slave.
ModBus-Function/Data Block
 Four Major Data Blocks
 From VA perspective, each Data Block has a separate zero-based
address space
 Coil Status – 1 Bit Read/Write
 Input Status – 1 Bit Read Only
 Holding Register – 16 Bit Read/Write
 Offsets specified in 16 Bit Words, but can overlay 32 bit and 64 bit float
types
 Input Register – 16 Bit Read Only
ModBus – Data Types
 Holding and Input Register Data Blocks support following types:
 Char – single ASCII character
 Signed 16 bit
 Unsigned 16 bit
 Float 32
 Double (64 bit float)
 Offset specified to access register in 16 bit Word Units,
 e.g., first 3 float 32 registers are:
myFloat32[0] , myFloat32[2], myFloat32[4]
 e.g., first 3 double registers are:
myDouble64[0] , myDouble64[4],
myDouble64[8]
ModBus –Register Attached Vars
 When ModBus Dest. Defined, Register Attached Variable is created
 Default Attached Var naming convention
 “MB[DestID][FuncID][TypeID]”
E.g., For IP@192.168.10.175 , Holding Register,
signed 16 => MB175HRs16
 Can change default attached var name to anything desired.
 Index attached var to access any register inside the associated
ModBus data block.
 e.g., myFloat32Var[20] , access 11th float32 reg
EtherNet/IP
 VA is the Server to a :
 Implicit Messaging Client
 E.g. ControlLogix 5550 Controller
 PCCC Client
 E.g. Allen-Bradley SLC5/05
EtherNet/IP – Implicit Message
 Use RSLogix 5000 SW to configure
 Add VA ETHERNET-MODULE in I/O Configuration folder.
 Enter VA IP Address, and Assembly object data,
Name
Assembly Instance
Size
Input
2
100
Output
1
100
Configuration
1
0
Add VA for Implicit Messaging with RSLogix 5000
EtherNet/IP – PCCC Client Setup
 Use RSLogix 500 SW to Configure
 In Channel Configuration Dialog, Configure Channel 1
(Ethernet)
 Add Message Instruction to Read or Write to VA.
 Target Device: PLC5 for VA
 Data Table Address,
writes go to VA Input Assembly Object,
reads are from VA Output Assembly Object
EtherNet/IP– Data Types
 SINT – Single ASCII character
 INT
- Signed 16 bit
 DINT - Signed 32 bit
 REAL - Float 32
 Register Indexing is type size aware
e.g., first 3 float registers are: myFloat32[0] ,
myFloat32[1], myFloat32[2]
 Definition of EtherNet/IP Dest. of a given type, overlays Input &
Output Assembly Objects with that type.
EtherNet/IP –Register Attached Variables
 When EtherNet/IP Dest. Defined, Register Attached Variable is
created
 Default Attached Var naming convention
 “EIP[TypeID]”
E.g., For real float 32 => EIPreal
 Can change default attached var name to anything desired.
 Index attached var to access any register inside the Assembly
data blocks.
 Register Write - operates on Input Assembly Object
 Register Read - operates on Output Assembly Object
Control Logix
 Uses Explicit Messages to:
 Query Global Scope and Program Scope Tags
 Read / Write Global Scope Tag variables
 Read Program Scope Tag Variables
 Supports user defined types
 Supported by Control Logix and Compact Logix
processors
GE Fanuc SNP (Series 90 Protocol)
 RS232 Serial Protocol for accessing
GE Fanuc Series 90 PLCs
 Protocol defines various Register Sets which the VA can
read or write .
Add SNP Destination with VA
GE Fanuc SRTP
 An Ethernet Protocol similar to SNP
 Allows connecting to GE Fanuc Series 90 PLCs with
an Ethernet Interface
MELSEC/Omron PLC
 VA is the Master to a :
 TCP/IP MELSEC Slave
 RS232 MELSEC Slave
MELSEC/Omron - Protocols
 MELSEC 1C ACPU
 MELSEC 1C AnACPU
 MELSEC 2C
 MELSEC 3C
 MELSEC 4C
 OMRON C
MELSEC/Omron – Data Types
 One Data Space supports following types:
 Unsigned 16 bit ( 1 Register WORD Size)
 Fixed point ( 4 Register WORD Size)
 Offset specified to access register in 16 bit Word Units,
 e.g., first 3 fixed registers are: myFixed[0] , myFixed[4],
myFixed[8]
MELSEC/Omron–Register Attached Variables
 When MELSEC Dest. Defined, Register Attached Variable is
created
 Default Attached Var naming convention
 “MLS[StationNum]_[ProtoId][TypeID]”
E.g., For Station 1 Protocol 1C ACPU/Format2
fixed point register => MLS1_1CAF2fp
 Can change default attached var name to anything desired.
 Index attached var to access any register inside the MELSEC data
block.
 e.g., myFixed[20] , access 6th (20/4+1)fixed point reg
 Index is always 16 bit WORD offset of register
Motoman MRC/XRC Protocol
 RS232 Serial Protocol to access
Motoman Robot Controllers
 Offers variables which controller can:
 Read with LOADV command
 Write with SAVEV command
 Supports types:
 BYTE, INT, REAL, Robot Axis in XYZ form
VA Functions
 Event Driven Functions
 User Functions
 Internal Functions
Event Driven Functions
 Solution Initialize
 Pre-Image Process
 Post-Image Process
 Periodic Functions
 Call with user specified frequency
 Input State Change Function
 Called when GPI rising/falling
Event Driven Functions(cont.)
 Delayed Event Functions
 Called specified delay after an event
 Image Received
 Image Processed
 PLC Variable Change of State
 Called when associated register changes value, actual register
must reside on VA
 Ethernet/IP
 Modbus Slave
User Functions
 Function a user defines to be called by other functions
 passed parameters
 returns a value
Internal Functions
 Math Functions
 String Functions
 Acquisition/ IO Control
 Logging History Control
 Misc
Math Functions
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sin(radians)
cos(radians)
tan(radians)
asin(x)
 arcsine of x in the range -p/2 to p/2 radians, where: -1 <= x <= 1.
acos(x)
 arccosine of x in the range -p/2 to p/2 radians, where: -1 <= x <= 1.
atan(x)
 arctangent of x in the range -p/2 to p/2 radians
atan2(y,x)
 arctangent of y/x in the range -p to p radians
exp(x)
 the exponential value of x.
logn(x)
 the natural logarithm of x
sqrt(x)
 square root of x
pow(x,y)
 x raised to the power y
String Functions
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find(substring, inString)
 finds first substring in the input inString, returns index of first character. Returns -1 if no match.
 Example: idx = find("00", "SM WRA 0057 4321") returns 7, or sets idx = 7.
substring(string, startIndex, length)
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forms a sub-string from the input string, beginning at startIndex (zero-based) of length characters.
 Example: s2 = substring("SM WRA 0057 4321" , 9, 0) returns string "57 4321" in s2.
strlen(string)
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returns the number of characters in a string.
getchar(string, index)
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returns the character located at index (zero-based) in the string.
setchar(string, index, char)
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sets the character in string, located at index (zero-based), to char.
int(string)
 converts the input string (of numbers) to an integer value.
 Example: x = int("33") sets x = 33
float(string)
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converts the input string (of numbers) to a floating point value.
 Example: x = float("57.499") sets x = 57.499
char( int )
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Converts integer to a character type
Acquisition/ IO Control Functions
 pulse(activeVal, offsetMillisec, durationMillisec)
 generates a pulse output. The pulse function can only be assigned to Global
Outputs GPO4 through GPO7 on VA40
 For Example, the statement: Global.GPO[4] = pulse(1,5,10)
 outputs on GPO4 an active-high pulse of 10 ms duration and offset 5 ms after the
statement executes.
 trigger()
 generate an image trigger signal. The Sensor Trigger must be set to "Inspection
Trigger" when using this function.
 triggersource(source)
 set the trigger source / mode to:
 freerun, internal timer, external trigger, or software
Logging/History Control
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logstart(fileName, onClient)
 Start logging the processed frame data to the specified CSV file.
 For Example, logstart(C:\Logs\iHistlog78.csv,0)
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logstop()
 Stop logging data that was started by a logstart call.
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logimage( fileName )
 Explicitly specify the file name for the next image logged on the server.
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resethistory()
 clears the history log of stored images and data.
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resetstatistics()
 clears the pass/recycle/reject counters.
Misc. Internal Functions
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copy(source, dest, numElements)
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Copy numElements from source (an array of elements) to dest (an array of elements. The copy function
can be used to cause multiple PLC registers to be updated in a single transaction.
For Example (update 3 Modbus registers):
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print(string, endOfFile)
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Send a string of data to the default printer.
timemillisec( )
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cmd[0] = x
cmd[1] = y
cmd[2] = z
copy (cmd, MB92HRs16, 3)
returns current time in milliseconds
getkey( )
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Returns a new keyboard input if available, otherwise immediately returns 0.