Installing Control Modules - Dräger Regard 3900 Instructions For Use Manual

Installation and set up
5.5.3 AC and DC Supplies
When used together, AC is the primary supply and DC is the backup supply. Diodes and/or relays may be required to switch
between the primary and the backup supplies.
Power AC / LED
When the controller is supplied with both AC and DC, it is optional to connect the 24 Vdc output from the PSU to the AC on
terminal on Sk2 on the display board. When connected, the Power AC /
the (primary) AC supply, and is off when the controller is supplied from the (backup) DC supply. Note that a diode is required to
prevent current flow from the backup supply falsely indicating a functioning AC supply.
Display board
5.6

Installing control modules

WARNING
!
Output modules are not included in the scope of the Regard 3900 ATEX EC-type examination. When an output module
is fitted, the controller cannot be used for control of countermeasures against risk of explosion.
The controller can have up to six control modules using the combinations detailed in Section 5.6.1. When fitting control modules
observe the following:
● Use the short pedestal screws for the lower level; use the long pedestal screws for the middle level; and use the long pedestal
screws and the plastic spacers for the upper level. (All of the screws have M3 threads.)
● Do not connect control modules outside the control panel of Regard 3900 and 3920 controllers.
● Refer also to the separate Assembly Instructions supplied for fitting control modules to a Regard 3910 controller.
Example showing two input modules and one output module
16
AC on
Sk2
LED is illuminated when controller is supplied from
Optional
0 V
+24 V
24 Vdc to
input modules
L
External
N
230 Vac
in
E
0 V
+24 V
External
0 V
24 Vdc or
+24 V
battery
Regard 3900 Series
3811
3812