Optically-isolated Digital Inputs
The digital input connections are implemented as four + and – terminals on 3.5 mm captive
screw terminal blocks. Because each input is optically-isolated, both connections must be
used to ensure the correct operation of the input circuit.
NOTE:
By factory default, status notification for Digital Inputs 1 through 4 is disabled.
To be made operational, they must be enabled using the
Set
input
trigger
on
MSVPP command (see “
Applicable MSVPP Commands
”).
The optically-isolated input circuits provide for various connection scenarios; two common
methods follow:
Option 1 —
Figure
76
shows a typical Digital Input application, monitoring external switch
positions. This application uses the Power port on the media player and is an application
where the current required is within the 1.8 A that the Power port makes available for
external use.
JMP 9600
Digital Inputs
JMP 9600
Power
JMP 9600
Input Terminals
Screw Terminals
1 kohm
Internal Configuration
+12V
Switch 1
Switch 2
GND
1
2
Figure 76.
Digital Input Connection Using the Power Port
Option 2 —
Figure
77
shows a similar external switch monitoring application, except that it
uses an external power supply. The external power supply is the preferred method in noisy
environments or when wiring is run over a long distance. The exact external power supply
voltage rating is not critical so long as the current through the 1-kohm resistor internal to
the media player is limited between 5 mA and 20 mA. Note the resistor in the input 1 circuit
in figure 77, which attenuates the current to within these limits.
JMP 9600
Digital Inputs
NOT
USED
680 Ohm
+24 VDC PS
+VE
-VE
Switch 1
JMP 9600
Input Terminals
Screw Terminal
Use twisted pair
wire for noise
cancellation.
1 kohm
Internal Configuration
+12V
GND
1
2
+5 VDC PS
+VE
-VE
Switch 2
+5VDC
JMP 9600
Power
Figure 77.
Digital Input Connection Using External Power Supplies
JMP 9600 Media Player • Detailed System Interaction
94
