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PRESYS
⏐ Instruments
Note the position of the jumpers in the following figure. The jumpers may be
localized on the front or the back side of the board, depending on its version.
Fig. 18 - Jumpers for selection of snubbers on the relay board
Alarm and control relays are extremely critical in control and safety of industrial
processes. In order to ensure the expected relay behaviour, consider the following two
loading conditions.
• High currents circulating through the relay contacts (from 20mA to 3A). When the
relay switches high currents there is the occurence of elecrical arch which damage
quickly the relay contacts. Besides, electrical noise is generated. In these conditions, it is
recommended to use the RC snubbers which come with the relay module (placed
jumpers).
• Low currents circulating through the relay contacts (less than 20mA). The relays could
not function properly when the jumpers are placed. In this case, the snubbers mantain a
4.5mAac/9.0mAac current when connected to a 120Vac/220Vac circuit. This current is
enough, in certain casses, to power a horn or alarm lamps, preventing their deactivation.
In this situation, there is no need to use the snubbers and the jumpers must be removed.
4.4 - Optional Module Connection
DMY-2030-F and DMY-2030-F Light Indicators accept up to four output devices
and communication, which must have the corresponding optional modules installed in
the instrument. Open the Indicator as shown in section 4.1 in order to access four
connectors in the Power Supply Board and one connector in the CPU board (refer to
Figure 19).
DMY-2030-F / DMY-2030-F Light
Jumpers 1 and 2
Maintenance
Page 27
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