Grass Valley XtenDD DD - Manual (Page 159)

7. Initial Installation
7 - 29 Planning and Installation - Rev. 3 / 04.2005
GPI Configuration The sliding switches T6, T8, T11, T13, T15, T18, T21 and T25 on the controller
board RY 3156.xx are assigned to the GPI inputs 1...8 (general-purpose inputs).
These inputs are provided with optocouplers. The switches enable to match the in-
puts to different control concepts:
Switch in position”1” (position ”left”)
A simple connection between the two connectors activates the corresponding in-
put. This kind of control is suitable for a connection to a relay contact or to an open-
collector output.
Attention: When connecting to an open-collector output, there is no ground po-
tential isolation between the switcher electronics and controlling de-
vices.
Since the circuit ground is led out of the device, the cabling has to be shielded for
this kind of control. Non-shielded cables may cause EMC and/or ESD problems!
Switch in position ”2” (position ”right”)
The optocoupler-internal LED is made available at the two connectors (including
1kOhm drop resistor). For this kind of control, a ground potential isolation is pro-
vided; the controlling device, however, has to impress a current upon the LED, i.e.
a simple contact is not suited in this case.
Due to the ground potential isolation, the cabling is less critical for this kind of con-
trol.