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PLC Engine Collect Data Sheet

PLC Engine Collect Data Sheet

Created by Werner Krings, Tani GmbH
Creation date: 2019.7.1, last modified 2022.2.15

Technical Data PLC Engine

The PLC Engine allows data processing in production lines. It connects controllers, devices, SCADA systems and databases from various manufacturers. It processes the data and dispatches them between the connected devices and other systems. It collects data, manages them and creates overviews for OEE applications.
Additional all the data can be handled over OPC. This are processed data and all data from the connected controllers, devices, OPC systems and databases.

PLC Engine is the perfect component for using it for communications in Industrie 4.0.

You will implement important use cases with PLC Engine
Optimize PLC Communication
Boosts the PLC communication with logical optimizing of the requests. Often this will happen to error texts from the controllers. The messages need to be fetched normally if the corresponding error number is changing and a new error condition becomes true. Without any change to Your SCADA system the communication speeds up. The main reason is less load on the communication line.
Copy PLC Data
Exchanges data between controllers and devices without PLC programming or SCADA functionality. That's how it's done: PLC Engine is reading the data from a controller or device and writes them into another controller or device. The writing normally takes place if the data are changing. With configurable triggers data which are depending on other data conditions for the writing can be defined. The data will converted if necessary. This is important if both controllers are different: One Siemens S7, the other a Rockwell Control Logix.
More complex handling is possible, too: Collecting of data from one or multiple controllers, do some calculation with the data, and write the result to a controller or device. Of course, any OPC compatible system can use the same data also.
Collect Data
Collects and processes data
PLC Engine is reading data from one or more controllers.
The data are collected and possibly calculated or normalized.
If all data are in place they are ready to process for other systems or OPC access.
During the logical processing the data are blocked for access.
Syncronous data access are waiting until the collection is finished.
Configurable error conditions are configurable: If one of the controllers is not available constant data are used, or an error number is processed.
PLC to Database
Exchanges data with common databases. You can read data from controllers and write them directly into common databases - with optional calculations. Data readed from databases can be written into controllers, too. All the data are available for OPC systems also.
Overall Equipement Effectiveness
Collects data over long time for OEE into a local or external database. So easily OEE applications can be build. The integrated websites are offering the collected and calculated data directly as curves or other. Additionally the data can be handled over OPC.


With logic tables you define all the things your plant will need:

Online diagnostics for shortening the configuration time


The configuration works in graphical style or with simple lists.

Lot of Wizards simplify this.

The example logs from barcode reader, adds a timestamp and writes both into a .csv file.

Logging to CSV file

This example reads a barcode, gets the print data from a database and prints the result.

Read database with a barcode, add print data and send them to the printer

Diagnostics boost the startup in plants. Use Your smartphone or tablet and all of the status displays.

Online diagnostics of logging to CSV file

The diagnostics logger handles longer running information collecting.

Diagnostics logger

OPC Interfaces

The maximum number of OPC clients is depending on used resources only. A PC from 2014 can handle multiple hundred connections.
All OPC interfaces are working locally in one PC or over network.
in case of Classic OPC Classic please do not use DCOM over networks, but it will be supported.
OPC UA supports the fast binary protocol. Security is supported in all variants. Multicast discovery is supported.
Data access data items are supported up to 200K each.

OPC UA functionality and limitations

The OPC UA implementation conforms to the specification 1.04.
The OPC UA Standard Model is supported, some extensions exist.
The OPC UA Alarms & Conditions module is supported.
An internal discovery server is active on standard, it supports multicast discovery also. It can be used as a global discovery server. Alternatively an external discovery server can be configured.

The session timeout will be limited to one hour.
The server and client certificate will be renewed if the Tani self signed certificate is used. All other certificates remain unaffected on expiring. The certificate validity is checked all 12h. It will be renewed seven days before it expires. Running connections will not be affected, new connections will use the new certificate.
AddNodes is supported with the following restrictions:

The security certificate key minimum length are

Traffic between different OPC interfaces (tunneling) is supported. It will be used for the OPC DA tunnels.

MQTT Interfaces

MQTT comes from the Internet of Things world. It is simple and fast.
A device can simultanously send data to multiple devices.
You can use the client and broker on the same device at the same time.

Controller Interfaces

All controllers will be connected over network. Often this is Ethernet, WLAN or other networks. All serial Ethernet and MPI Ethernet gateways for industrial controllers usage are supported.

Configuration Interfaces

The configuration can be done with the shipped configuration software or over OPC with the System topic.
The connection  for the configuration is encrypted with TLS 1.2. The encryption can be switched off for usage in countries where encryption is forbidden.

Network Redundancy for connections to controllers and devices

Connections to devices and controllers are supporting network redundancy.
Double and triple redundancy can be selected.
Two redundancy operation modi are possible.
In dynamic redundancy any of the connections is working as master. If it breaks another connection becomes the master connection.
In static redundancy the first connection is the master. If it breaks another connection becomes the master. If the first connection works again it will become the master connection again.

The connections of the redundancy should work on different network adapters.The adapters need different IP subnets for properly work.

Controller Types and Controller Protocols

Communicates via Ethernet.


BACnet will be used over IP / UDP.
Maximum length of strings: 256 Byte
Status text elements are supported (state_text)
Supported charsets: UTF-8, UTF-16, Latin-1
Unions ("Choice") and structures ("Sequence") are existing for important values as trend, shedule, calendar, prioriry.
The trend data are offered as history data. All unimplemented instances will not be shown.
Enum values are represented as UINT32. Some special enum are handled as bool.
Values in "Octet-String" and "Bit-String" can be written in whole only.

BBMD (BACnet Broadcast Management Device) details

BBMD will be used during the connection establishing and the device search if the devices do not be all in the same collision domain. BACnet uses broadcast during ist connection establishing.
There are several procedures in BBMD:

Additionally BBMD can be used connecting older serial only installations to the IP network.

COV (Change Of Values) details

COV represents the event subsystem of BACnet. Events will be offered in browsing the variables, they will be subscribed. If the device will send the data the event will be generated.
Because BACnet is working with UDP the COV receive can not be guaranteed. Tani is offering an option: If no event will be received during the reconnection time from the configured connection it will be polled. If the value did not change no event is send for this polling.

BACnet - Writing values with priority-array

These object types have a priority-array in addition to their present-value property: The BACnet spec says: The Tani implementation works as follows:

This mechanism was chosen to allow choosing the write priority via OPC without changing the read syntax for present-value property. This also allows writing NULL values via OPC.

Implemented Properties

The following object properties are implemented:

Object TypePropertyBACnet TypeOPC TypeRemarks
allallBit StringArray of Boolean
allallCharacter StringString
allallOctet StringArray of UInt8
allChange of State Time (16)BACnetDateTimeDateTime
allEvent Time Stamps (130)Sequence of BACnetTimeStampArray of Structure "Timestamp"
allObject Type (79)BACnetObjectTypeUInt32
allTime of Active Time Reset (114)BACnetDateTimeDateTime
allTime of State Count Reset (115)BACnetDateTimeDateTime
Access Door (30)Door Alarm State (226)BACnetDoorAlarmStateUInt32
Access Door (30)Present Value (85)BACnetDoorValueUInt32
Access Door (30)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "UnsignedPriorityValue"see section "Priority Array"
Access Door (30)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Analog Input (0)Present Value (85)RealFloat
Analog Input (0)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Analog Output (1)Present Value (85)RealFloat
Analog Output (1)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "AnalogPriorityValue"see section "Priority Array"
Analog Output (1)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Analog Value (2)Present Value (85)RealFloat
Analog Value (2)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "AnalogPriorityValue"see section "Priority Array"
Analog Value (2)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Averaging (18)Maximum Value Timestamp (149)BACnetDateTimeDateTime
Averaging (18)Minimum Value Timestamp (150)BACnetDateTimeDateTime
Binary Input (3)Present Value (85)BACnetBinaryPVUInt32
Binary Input (3)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Binary Output (4)Present Value (85)BACnetBinaryPVUInt32
Binary Output (4)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "UnsignedPriorityValue"see section "Priority Array"
Binary Output (4)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Binary Value (5)Present Value (85)BACnetBinaryPVUInt32
Binary Value (5)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "UnsignedPriorityValue"see section "Priority Array"
Binary Value (5)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Calendar (6)Datelist (23)List of BACnetCalendarEntryArray() of Structure "BACnet.CalendarEntry"
Device (8)Last Restore Time (87)BACnetTimeStampStructure "Timestamp"
Device (8)Local Date (56)DateStructure "Date"
Device (8)Local Time (57)TimeStructure "Time"
Device (8)Object List (76)Sequence of BACnetObjectIdentifierArray of UInt32
Device (8)Protocol Object Types Supported (96)BACnetObjectTypesSupportedArray of Boolean
Device (8)Protocol Services Supported (97)BACnetServicesSupportedArray of Boolean
Device (8)Segmentation Supported (107)BACnetSegmentationUInt32
Device (8)System Status (112)BACnetDeviceStatusUInt32
Device (8)Time of Device Restart (203)BACnetTimeStampStructure "Timestamp"
Event Enrollment (9)Object Property Reference (78)BACnetDeviceObjectPropertyReferenceStructure "DeviceObjectPropertyReference"
File (10)Modification Date (149)BACnetDateTimeDateTime
Life Safety Point (21)Present Value (85)BACnetLifeSafetyStateUInt32
Life Safety Point (21)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Life Safety Zone (22)Present Value (85)BACnetLifeSafetyStateUInt32
Life Safety Zone (22)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Load Control (28)Actual Shed Level (212)BACnetShedLevelStructure "ShedLevel"
Load Control (28)Duty Window (213)UnsignedUInt32
Load Control (28)Expected Shed Level (214)BACnetShedLevelStructure "ShedLevel"
Load Control (28)Present Value (85)BACnetShedStateUInt32
Load Control (28)Requested Shed Level (218)BACnetShedLevelStructure "ShedLevel"
Load Control (28)Shed Duration (219)UnsignedUInt32
Load Control (28)Start Time (142)BACnetDateTimeDateTime
Loop (12)Controlled Variable Reference (19)BACnetDeviceObjectPropertyReferenceStructure "DeviceObjectPropertyReference"
Loop (12)Manipulated Variable Reference (60)BACnetDeviceObjectPropertyReferenceStructure "DeviceObjectPropertyReference"
Loop (12)Setpoint Reference (109)BACnetSetpointReferenceStructure "SetpointReference"
Loop (12)Present Value (85)RealFloat
Loop (12)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Multi State Input (13)Alarm Values (7)Sequence of UnsignedArray of UInt32
Multi State Input (13)Fault Values (39)Sequence of UnsignedArray of UInt32
Multi State Input (13)Present Value (85)UnsignedUInt32
Multi State Input (13)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Multi State Output (14)Present Value (85)UnsignedUInt32
Multi State Output (14)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "UnsignedPriorityValue"see section "Priority Array"
Multi State Output (14)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Multi State Value (19)Alarm Values (7)Sequence of UnsignedArray of UInt32
Multi State Value (19)Fault Values (39)Sequence of UnsignedArray of UInt32
Multi State Value (19)Present Value (85)UnsignedUInt32
Multi State Value (19)Priority Array (87)BACnetPriorityArrayArray(1..16) of Structure "UnsignedPriorityValue"see section "Priority Array"
Multi State Value (19)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Notification Class (15)Recipient List (102)List of BACnetDestinationArray() of Structure "BACnet.Destination"
Schedule (17)Effective Period (32)BACnetDateRangeStructure "DateRange"
Schedule (17)Exception Schedule (38)Sequence of BACnetSpecialEventArray of Structure "SpecialEvent"
Schedule (17)List of Object Property References (54)Sequence of BACnetDeviceObjectPropertyReferenceArray of Structure "DeviceObjectPropertyReference"
Schedule (17)Present Value (85)ABSTRACT-SYNTAX.&TypeStructure "Any"
Schedule (17)Schedule Default (174)ABSTRACT-SYNTAX.&TypeStructure "Any"
Schedule (17)Weekly Schedule (123)Sequence Size(7) Of BACnetDailySchedule7 sub-objects ("Monday", "Tuesday", ...) of Structure "TimeValue"
Pulse Converter (24)Present Value (85)RealFloat
Pulse Converter (24)Status Flags (111)BACnetStatusFlagsArray(0..3) of Boolean
Structured View (29)Subordinate List (211)Sequence of BACnetDeviceObjectReferenceArray of Structure "DeviceObjectReference"
Trend Log (20)Client COV Increment (127)BACnetClientCovStructure "ClientCov"
Trend Log (20)Log Buffer (131)BACnetLogRecordStructure "LogRecord"Accessed via "HistoryRead" function, "Read" shows only one record.
Trend Log (20)Log Device Object Property (132)BACnetDeviceObjectPropertyReferenceStructure "DeviceObjectPropertyReference"
Trend Log (20)Start Time (142)BACnetDateTimeDateTime
Trend Log (20)Stop Time (143)BACnetDateTimeDateTime


KNX will be used over IP / TCP and IP / UDP.
The symbol import is using the standarized ESF files.


PLC Engine is a database client. It connects with user and password to the database.
The standard SQL statements INSERT INTO, UPDATE, SELECT, DELETE, FUNCTION and PROCEDURE will be used over the wizards. Other statements will be configured directly.
Supported are:

Multiple databases can be handled simultanously.
In one database multiple sub databases can be used.
During the configuration the databases will be browsed. This will require depending on the type of the database or the interface a username and a password, possibly more.
The database itself need to be configured that it can be accessed.
PLC-Engine will need an account on each database.

For using PLC Engine on a PC the locally installed databases can be used also.
On PLC Engine Device a My SQL database is installed. This database will be managed completely by PLC Engine.

TANI PostgreSQL Integration

The TANI PostgreSQL driver explicitly supports all data types listed in the following table. All types not listed here are implicitly converted to the "text" type and handed to the PLC Engine as a single String.

PostgreSQL typeArray typeOPC typeDescriptionNotes
booleanboolean[]BitTruth state (true or false)
bit varying(n)
bit varying(n)[]
BitBit vector of (maximum) length n
Int1616-bit signed integer
Int3232-bit signed integer
Int6464-bit signed integer
UInt3232-bit unsigned integer
realreal[]Float32-bit floating-point value
double precisiondouble precision[]Double64-bit floating-point value
Doubleexact fixed-point valuethe values are converted to floating-point values, this may lead to loss of precision
timestamp with time zone
timestamp with time zone[]
TimestampTimestamp values (date + time)a time zone (if present) is ignored
datedate[]TimestampDate valueThe time part of the OPC Timestamp is set to 00:00:00
time with time zone
time with time zone[]
TimestampTime valuesa time zone (if present) is ignored
The date part of the OPC timestamp is set to 1970-01-01
char varying(n)
char varying(n)[]
StringCharacter strings (of (maximum) length n)

General note: all multi-dimensional arrays (including arrays of vectors) are flattened to a single-dimensional array. The identity of the multiple dimensions is lost. This is a limitation of the internal data handling of the TANI software. Example: {{1,2},{3,4}} is returned in the logic table as {1,2,3,4}. Writing of multi-dimensional arrays (using INSERT or UPDATE) is not supported.

Logger for diagnostics

The OPC Server contains a logger for diagnostics purposes during plant startup. The logger can be configured. The system load can be big if all controller data in big plants are logged.


Maximum number of configurable client connections: 4000.
Maximum length of a single item: 4GB.
Maximum number of elements each connection: 1 million.
Maximum number of elements (Items): 16 million.
Maximum OPC groups each connection: 100.
Maximum number of passive connection for each port is 999.
The OPC synchronous functions returning a bad quality immediately if the PLC connection is not established.
Changes in controller configuration will be checked all 10 seconds if the PLC does not offer a mechanism for this check during write.
Fields can be up to 64K in length each.
Multi dimensional arrays can have up to six dimensions.

Fields can be up to 64K in length each.The maximum amount of configurable logic tables is 60000.
The maximum length of one logic table is 4GB.
Maximum number of entries on a logic element 60000.
File operations can handle up to 64K in each request. Adding data to a file is limited only by the space on the disk.
Multi dimensional arrays can have up to seven dimensions.

Virtual Connections

Virtual connections provide a start point mostly used as destination for redirects.
A virtual connection has connection rights. The redirect destination in this connection will offer the rignts of the virtual connection. As in the logic tables and the status variable lists the source rights are ignored.
Symbols for the virtual connection can be defined in the symbol editor.
One PLC element can be used once in one virtual connection.

Depending on the license the limits can be less.


The throughput will be mainly limited by the controller speed or the reaction time of OPC applications.
Read requests to the controller will be optimized as much the controller is supporting this. For that elements will be collected to blocks reading more than requested, but not for inputs and outputs. These optimizing can be affected by configuration separately for each connection. Optimizing can be switched off, too.
Write requests to the controller are collected or handled in that order the application did called the system.
On OPC all optimizing the individual OPC uses is supported.
The normal time in cyclic controller requests is 50ms.It can be faster if the controller polling interval is set to zero.
Only data are sent to OPC which did change in the controller between two read requests.

The throughput of one logic table normally will be handled below 10ms. Lot amounts of logic tables containing much of mathematics functions may rise the 10ms. This is true especially on embedded devices without a mathematical co processor.
No handling can be faster than the controller and device data acquisition. The same is true for database access.


Logic tables

Logic tables are constructed for linear logic. Loops are not possible.

Sequence chains

A sequence chain supports the maximum of 65535 steps each.

Error Handling in Logic Tables

All logic elements which functions can fail are supporting an OK bit. The user need handle this preventing unexpected run-time behavior.

Variables and Structures

Structures can not contain loops.
A structure or variable can be up to 4GB in its size.

Status Diagnostics Lists

The status diagnostics lists are supporting arrays up to 100 values each. If an array is longer than 100 values the first 100 elements are shown only. Writing this array is not possible.

Field and text optimizings

The from version 1.8 existing field optimizings will prevent reading the long fields too often, the index is requested on standard only.This optimizing bases of the fact that the index does net changed too frequently.

Usage of memory

Usage of computation time

The consumed computation time is depending on the load with communication. Most the time it will be waited for controller data or OPC application reaction.
All software is working with events. This maximizes the throughput and minimizes the usage of computation time.
Multiple CPU are supported. Up to ten CPU will be used, the main work will be handled by three CPU.


The installation does depending on the product install multiple parts separately. On uninstall not all products are deleted automatically. But all installed products can be deleted over the menu or the software part in the system control manager.
The user settings will be preserved and not deleted during uninstall.

Operating systems