The interface of hardware is separated in two parts: the interface of input and the interface of output. Just about the same functions are present in both parts but they are processed in the differing order.
The following description of process flow of a wired input coming from a plant system describes the working of this interface:
· The signal is agitated between the input board of the PLC and the plant system.
· In a first function of software called the “Inputs Wrapper”, the signal is duplicated from an area of I/O addressing to an area of DB addressing, e.g. Input “I0.0” is duplicated to “DB1.DBX0.0”. Note: PLC complete addressing is employed here for better understanding, but signs should be used. Now, the signal becomes a joint DB variable.
· If the signal is Boolean, the variable goes through via a layer of “Anti-Rebounce”.
· The joint DB variable is transferred to a block of “Interface Switch” where the judgment is made to utilize the signal coming from a simulator or a wired signal. Another joint DB variable is issued.
· The joint DB variable issued is transferred to an “FBS Wrapper”, where the variable is duplicated from a component naming convention to an FBS Level 3 convention or FBS-L3.variable. Another joint DB variable is issued.
· From the “FBS Wrapper”, the joint DB variable can be practiced, base on if it is a numerical, originally from an analog signal, or a variable of Boolean, originally from a digital signal.
- Variable of Numerical: is changed to a value of engineering base on a look up table, or a linear regression, etc… Conversion of Signal to Engineering. Another joint DB variable is issued.
- Variable of Boolean: here the value of Boolean can be reversed or not, base on the logic the developer desires to use in the core application. For instance, so as to have fail-safe logic, the device status could be notified by a signal of “0V”, which is more suitable for encoding a “TRUE”. Another joint DB variable is issued.
The variable goes through a layer of “Forcing”, where its value can be strengthen by the user for maintenance or commissioning purposes. The variable is issued by the input interface of hardware.
- The variable is transferred systematically to the “States Variables” CODAC Interface transmission mechanism and can be employed by the core application of PLC.
PLC WorkShop for Modicon of Quantum VME Configuration
The Bus extension of Quantum VME allows a card control data of VME-424/X moves between elements of a Quantum network master/slave
Merge Ladder Check Box of PLC WorkShop
This check box is originally ticked and the range of default is the minimum number segments for both programs and networks maximum, for every segment, in the source of program.
Hardware Setup and Software Installation of PLC Logicmaster
The Work Station Interface (WSI) Board provides a high-performance serial interface between a Series 90-70 PLC and the programmer for the WSI version of Logicmaster 90-70 software. There are two Work Station Interface Boards available; one is for an AT-type computer, and the other is for a PS/2-type computer.
