In an effort to allow customers more flexibility with overall system performance Compumotor has implemented the SYSPER command. This command allows customers the ability to speed up command processing by slowing down other functions of the controller. Command speed improvement varies by how many features are utilized, but a 40% command performance improvement using SYSPER4 is not uncommon.
Every 2 ms in the 6K an interrupt service routine updates all the I/O, PLC scan mode, and following/contouring calculations, and communications, including Ethernet. After these items have been updated, the remaining time in the ISR is dedicated to command processing. If several of these features are enabled, less time is available for command processing, and command processing performance decreases. The 2ms ISR is set with the SYSPER command. The default for this command is 2ms. The ISR can also be set to 4ms. Setting SYSPER to 4 will only update the items in the ISR every four 4ms instead of every 2ms. In other words, features such as PLC scan mode will be update every 4ms instead of every 2ms. By slowing down the ISR more time is left over for command processing. In a 6K controller with many of the above features enabled, command performance can be significantly increased by changing to SYSPER4. Compumotor has realized greater than 40% improvement on command processing when the controller is lightly loaded, and a 10 times improvement when the controller is heavily loaded.