20% timeslice is the default - try setting it up.
Your scan time is fast - so it seems this application has more comms than logic. So, if you're running ControlLogix V16 or higher, don't be afraid to wind the timeslice up and up and up, but be sure to check the box that lets the processor use unused timeslice for normal processing.
I once had one application with the timeslice set to 75%, just to handle the MSGs for the 1771 I/O that was attached. Sounds like a similar scenario.
Make full use of the number of message buffers available in the Processor and the DHRIO modules - i.e. don't do a daisy-chain "1 message at a time" coding. Allow simultaneous message triggering, up to the limit imposed by the modules.
I've worked on PLC5 to CLX upgrades where huge amounts of 1771 I/O was attached via DHRIO modules, and got great results - with careful consideration of the messaging restrictions.
Your scan time is fast - so it seems this application has more comms than logic. So, if you're running ControlLogix V16 or higher, don't be afraid to wind the timeslice up and up and up, but be sure to check the box that lets the processor use unused timeslice for normal processing.
I once had one application with the timeslice set to 75%, just to handle the MSGs for the 1771 I/O that was attached. Sounds like a similar scenario.
Make full use of the number of message buffers available in the Processor and the DHRIO modules - i.e. don't do a daisy-chain "1 message at a time" coding. Allow simultaneous message triggering, up to the limit imposed by the modules.
I've worked on PLC5 to CLX upgrades where huge amounts of 1771 I/O was attached via DHRIO modules, and got great results - with careful consideration of the messaging restrictions.