How do I use a multifunction block to control direction from a digital input?
Use one of the MULTIFUNCTION blocks in SIGN CHANGER mode. Basically, take your present final speed demand (the output of the RUN MODE RAMP block) through one of the MULTIFUNCTION blocks and control the polarity with a digital input. See the default block diagram in the PLX manual to see where it goes - between the RUN MODE RAMP GOTO and PIN 65.
Specifically, proceed as follows:
Go to CONFIGURATION, ENABLE GOTO,GETFROM and set to ENABLED
Go to CONFIGURATION, BLOCK OP CONFIG, RUN MODE RAMPS GOTO and set it to 300)ANALOG POST 1 (or another post if already in use) Go to APPLICATION BLOCKS, MULTI-FUNCTION 1, 544)MULTIFUN1 MODE and set it to SIGN CHANGER
Go to APPLICATION BLOCKS, MULTI-FUNCTION 1, GET FROM and set it to 300)ANALOG POST 1 (or whichever post you used)
Go to APPLICATION BLOCKS, MULTI-FUNCTION 1, GOTO and set it to 65)RAMPED SPD REF 4
Go to CONFIGURATION, DIGITAL INPUTS, DIP1 (T14) SETUP (or whichever digital input you want to use) and set its GOTO to 545)MULTIFUN1 OP SEL
Go to CONFIGURATION, ENABLE GOTO,GETFROM and set to DISABLED Digital input 1 then controls the polarity of the final speed reference signal from the RUN MODE RAMP block into the SPEED CONTROL block. Please see section 3.10 of the APPLICATION BLOCKS manual for more info on the MULTIFUNCTION blocks.
Don't forget to perform a PARAMETER SAVE once you are happy with the functionality.