Optimizer settings

The communication to the controls can be optimized in many different details.

The Poll Interval determines the rate at which the data from the controllers are requested. The default value is once per second, 1000ms.

Frequent inquiries increase the response time in SCADA systems, but this can also put a strain on the controls.

The Application timeout detects when a controller stops responding e.g. Because it has been turned off.

The Reconnect timeout determines when the connection will be reestablished after connection errors.

The Maximum read gap determines  how large the gap (in bytes) between the individually requested items within a data block may be, without forming a new block.

This increases the throughput, but can also be slow with slow controllers - especially with serial-connected systems.

This value is not used when accessing peripherals such as inputs and outputs.

If the value is 1 or zero, all non-contiguous data is requested individually.

With a connection to an S7-1500 or S7-1200 with optimized access, the value 0 deactivates the optimization, which means that reading can be slowed down accordingly.

Optimize reading input and output elements: some controllers don't allow to read multiple inputs or outputs in a single request. In this case uncheck that check box.

Sync read handling

For synchronous reading, this function can be set to normal cyclic reading. Synchronous reading can also read existing data from the buffer. Normally, synchronous read jobs are processed with high priority and separately.

These settings are used with some OPC clients, which read all data synchronously and often run too slowly.

Write handling

When writing to the controller

Optionally, the written data can be immediately used as read data. If this is not selected, the read data is not updated until the next reading from the PLC.

Writing actualizes read data immediately: the written value is sent to the client before it has been written to the PLC.

Writing forces read update: if an item is written, the client will definitely receive a value change or update the next time it is read, even if it has not changed.

Special settings

Very old controllers don't allow to request more data areas in one ethernet frame. Enable it only when the controller response is an error when this option is disabled.