Clear-Com LMC-64 - Manual (Page 106)

Clear-Com
Eclipse Median Instruction Manual
7 - 2 0
The general-purpose inputs operate in one of two modes: the
“opto-isolated” mode or the unisolated mode. The opto-isolated mode
requires the externally connected equipment to provide the current to
power the general-purpose input. The non-isolated mode does not
require that the externally connected equipment powers the
general-purpose input. The current is supplied by a voltage output on
the GP IN connector.
To select a mode, move the J1 jumper on the CPU rear card to one of
two positions. The J1 jumper is located on the inner-matrix side of the
DB-25 connector.
• For opto-isolated mode, fit the J1 jumper across pins 1 and 2.
• For non-isolated mode, fit the J1 jumper across pins 2 and 3.
Note: It is recommended that the connector is set to the fully
opto-isolated mode.
Opto-Isolated Mode
Figure 7-13 shows the opto-isolated connection.
Figure 7-13: Opto-Isolated Connection to Eclipse Median GPI
Connector
In this mode, a DC voltage of between 7 and 24 volts is required at the
EXTVIN+ pin with relation to the EXTVIN– pin. To cause an input to
detect an active signal, current must flow from the relevant input pin.
The external device should draw no current to cause an inactive input
and at least 5 mA to cause an active input. The opto-isolator drive line
contains a 1.5 kOhm resistor to limit the current through the
opto-isolator. Therefore the input pins can be connected directly to the
EXTVIN– level to cause an active input.
The voltage level at the external input pin should not be allowed to go
below EXTVIN– or above +6 V with respect to EXTVIN–.
Non-Isolated Mode
Figure 7-14 shows the non-isolated connection.
+ C
10uF_10V D
BYG22D + C
10uF_25V
INPUT 1 EXTVIN-
EXTERNAL INPUT 2
EXTVIN+
INPUT 2
R29 1.5K
U
LM78L05ACM
VIN
8
VOUT
1
7-24V
R30 1.5K
U
MOCD207-M
1
3
2
4
8
7
6
5
EXTERNAL INPUT 1
R
33K2
+3V3
R
33K2
+3V3