THOMSON DD10, Руководство по установке

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6. Initial Installation Diamond digital
80
GPI Configuration The sliding switches T47, T48, T49, T56, T57, T58, T67 and T68 on the p.c. boards
RY 1601 and RY 1917 are assigned to the GPI inputs 1...8 (general-purpose in-
puts). These inputs are provided with optocouplers. The switches enable to match
the inputs 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: In this case, both lines are connected with the circuit ground. When
connecting to an open-collector output, there is no ground potential
isolation between the switcher electronics and controlling devices.
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.