15
If the above instructions are followed, and the precautions specified in
[Section
1.2 Safety instructions]
are taken, the risk of damaging equipment and assets or
endangering life and limb can be significantly reduced.
The PQM 1588 is equipped with seven output relays. Indicating units are connected to these via
current-amplifying electromechanical devices (relays, contactors).
Alarm signals generated internally in the instrument can be assigned to the volt-free contacts of
the alarm relays using the SYSTEM-SW software. These alarm signals can comprise status sig-
nals, status of the optional digital inputs, set alarm limits being exceeded or device faults.
See
[Section 2 Technical Data]
, for the relevant technical data.
See
[Section 7 Configuration], for the configuration procedure.
The connections to the terminals „
Alarm 1, Alarm 2
and
OUT 1
to
OUT 5
“, must be made as
shown in
Figure 2: PQM connections
.
5.3.1 Alarm 1 Relays
Alarm relay 1 is a bistable type. This means that after a power outage, the relay contacts remain in
the same state as they were before the outage.
5.3.2 Alarm 2 Relays
Alarm relay 2 is an NO (‘normally open’) type. Unlike alarm relay 1 it is not bistable. During opera-
tion with no interruptions to the power supply, its contacts remain closed. In the event of a fault
they open. This means that an alarm is given even if power is cut off to the PQM 1588 or there is a
break in the alarm circuit.
Under the
Alarms
heading in SYSTEM-SW alarms from various sources can be assigned to alarm
paths. A switching output not yet allocated or an alarm contact can be selected as alarm path, but
it is standard practice for the Alarm 2 contact—unlike the other switching outputs—to be ‘inver-
ted’. In other words, whereas the normal switching outputs and Alarm 1 close their contacts when
an alarm occurs, the contacts of Alarm 2 open.
5.3.3 OUT 1 to OUT 5 Relays
The relays OUT 1 to OUT 5 are of the bistable type. This means that after a power outage, the
relay contacts remain in the same state as they were before the outage.
5.4 RS-485
Two bus connections RS-485 BUS 1 and BUS 2 are available from hardware version 2 of the
PQM 1588 onwards. The hardware version is stated on the nameplate; it also constitutes the first
numeral of the software version.
These two connections can be seen to the left and the right of the Ethernet interface as shown
below in
[Figure 3: Bus connections]
.
