I would like to use the dig4 channel to control the MCS6A. I'm trying to understand if and how it is possible to select this option directly from the DLL functions and not using the MPANT software.
The parameter digio controls the use of the digital I/O port.
If you want to set controlling by dig4 input via the DLL, send a command "digio=10". The number 10 is in hexadecimal format, bit 4 is "1" and all other bits are 0.
See in the online help "How to use the control language" the description of the digio parameter:
digio=0 ; Use of Digital I/O (hex):
; bit 0: DIG I/O bit 7 output status
; bit 1: Output digval and increment digval after stop
; bit 2: Invert Polarity
; bit 4: Input pin 4 Trigger System 1
; bit 8: GOWATCH
; bit 9: GO High at Start
; bit 10: GO Low at Stop
; bit 11: Clear before external triggered start
; bit 12: Only triggered start
If you send then a "start" command, the acquisition will not immediately started but after a change of the Dig 4 input TTL level from high to low.