Optimizing Client To Server Communications

Due to this driver being a front-end/back-end driver, there are no transport delays between Plant SCADA and the driver involved in processing a read request from the driver cache. This means that under heavy loads, the driver could use up most the CPU processing requests. The driver can tune the CPU usage and throughput to help manage the resources of the I/O server. The standard driver parameters MaxPending and Delay can be used as follows:

[ABCLX]
MaxPending=x
Delay=y

Where:

• x = the maximum number of simultaneous requests the driver will receive from Plant SCADA.

• y = the average delay applied to the requests to control CPU usage.

Examples

[ABCLX]
MaxPending=256
Delay=50

The above example would mean that the driver is capable of servicing 256 requests every 50 milliseconds.

[ABCLX]
MaxPending=1
Delay=0

This example would mean the driver would reply to every request as quickly as possible, which could cause CPU issues.