Elgas DATCOM, Operating Instructions Manual

Page: 131 / 228

7
Technical Description of the Device
129
 When using a NAMUR (S0-NAM) encoder with the measurement frequency of less than 1
min
Using external power supply for the device is recommended:
 For frequent communication (more than once a day),
 When longer time ON of the modem than specified in paragraph 7.5.3 is requested
In order for the device or modem to be powered externally, it must be fitted with an appropriate
plug-in module to which an external intrinsically safe source is connected. The supplied
intrinsically safe sources must be powered from a 12 Vdc source.
i
The device batteries and modem batteries must be inserted and connected in
the device even when external power supply is used.
In the event of the external power supply failure, the device and the modem
are switched automatically to battery operation. In this case, the batteries
serve as backup power supply.
External power
supply
External power supply
module
IS source
Module Installation
Type of
source
Installation
Device S3-PWR1 SLOT 3 PS-E, PS-E/A Out of potentially explosive
atmosphere
Internal modem S4-PWR2 SLOT 4 PS-M, PS-
M/A
Out of potentially explosive
atmosphere
Table 18 External power supply, components required
The wiring diagram for the external supply of the device is specified in Section 5.6.6.1.
The wiring diagram for the external supply of the modem is specified in Section 5.6.6.2.
7.6 Digital Outputs, Modified Use
ELCOR has 2 digital outputs DO1 and DO2 in basic design, ELCOR plus and ELCOR plus Indexer
have 4 digital outputs DO1 to DO4. These outputs run to the DOUT terminal block of the
input/output board (I/O board). All outputs are galvanically isolated and are of the open collector
type.
The basic use of these outputs required feeding these outputs externally by supplying voltage to
the U0 + terminal of the DOUT terminal block. In this case, the shorting jumper JP1 must not be
fitted to the I/O board.
For pulse outputs, however, it is possible to set a special mode of use for DO1 and DO2 outputs
where these outputs can be operated as pulse outputs without power supply at terminal U0 +.
This method of use requires a shorting jumper JP1 on the I/O board (see Fig. 63).
Notice
Special mode (with fitted jumper JP1) is intended only for special cases of
connection of the device with another device when it is not possible to use
the supply terminal U+.
The condition for its use is that the voltage from the connected device, which
is connected to the output DO1 (DO2), must not have a voltage greater than