GE PACSystems RX7i Reference Manual

Also see for PACSystems RSTi-EP: User manual CPU Programmer's Reference Manual

Contents

GE PACSystems RX7i Reference Manual Manual pdf 222 page image

Chapter 6. Serial I/O, SNP & RTU ProtocolsGFK-2222AD April 2018 2116.2.5 Overlapping COMMREQsSome Serial I/O COMMREQs must complete execution before another COMMREQ can be processed.Others can be left pending while others are executed.COMMREQS that Must Complete Execution■ Autodial (4400)■ Initialize Port (4300)■ Set Up Input Buffer (4301)■ Flush Input buffer (4302)■ Read port status (4303)■ Write port control (4304)■ Cancel Operation (4399)■ Serial Port Setup (FFF0)COMMREQs that can be Pending While Others ExecuteThe table below shows whether Write Bytes, Read Bytes and Read String COMMREQs can be pendingwhen other COMMREQs are executed.NEW COMMREQCurrently-PendingCOMMREQsAutodial(4400)Write Bytes(4401)Initialize Port(4300)Set Up InputBuffer (4301)Flush InputBuffer (4302)Read PortStatus (4303)Write PortControl(4304)Read Bytes(4402)Read String(4403)CancelOperation(4399)Serial PortSetup (FFF0)Write Bytes(4401) No No Yes Yes Yes Yes Yes Yes Yes Yes NoRead Bytes(4402) No Yes Yes No No Yes Yes No No Yes NoRead String(4403) No Yes Yes No No Yes Yes No No Yes No