Monday, June 13, 2011

The Variables of CTI 2500 Series PLC

Unexploited physical bases might be selected as virtual bases in the RPM. Every of these bases of virtual contain of sixteen virtual I/O slots of 32WX/32WY. Every slot might be utilized to plan vital variables into the communications link of remote I/O. Computing Home base, the virtual bases maximum number supported is 15 minus the number of physical bases.

Determining the critical variables
Data is moved between every PLC every scan to maintain the programs from deviating. The data moves will avoid undesirable performance in the backup PLC in the switchover event to the backup PLC. For example, we desire to prevent any I/O from being knocked. High-speed counters have to protect current counts. The sequencer current of drum steps and current calculates of the step should be moved. Any linking control relays that straight influence outputs will also require to be moved. Any computations that result in straight control will also require to be transferred. The good practice is to transfer all “Y” output and “C” control relays.

Retrofitting an available program
Observe the existing ladder program and decide which variables are significant to the system. Added ladder logic will be needed to move these variables to a memory table of V. These amends will be added to move data to memory of V and then to move to WY addresses. significant variables might be moved to a memory table of V or straight to a WY address. Every defined variable in the PLC will require to have extra ladder logic to move the register for transfer. Additionally the ladder program will have to be distorted to get the variable when in mode of stand-by and renew the register in the PLC. In the lively PLC the variables are moved from the PLC to space of the WY address.

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