Table of Contents
Advertisement
HA71 Digital Gas Controller
2.3.1 Common Alarm Relays 1 and 2
CAutIoN
Read this section carefully and test all settings by simulating HA71
input conditions that should activate these alarm relays!
Common Relay 1 and Common Relay 2 menus are identical and
therefore discussed only once. It is very important to fully understand
these menus since they determine the functions of each common
relay.
Figure 2-10. Common Relay 1 and Common Relay 2 Menu
•
The
Group menu entry offers additional flexibility by controlling
which channels trip this menu's common alarm relay. The 3
choices are 1-16, 1-8 or 9-16. Some applications have different
types of sensors, or, sensors in different areas connected to the
same HA71 Controller. In these cases, it may be undesirable
for a sensor on channel 9 to trip the same relay as a sensor on
channel 2. The Group menus may restrict this. For example,
channels 1-8 might be set to trip common relay 1 while channels
9-16 trip common relay 2. Another possibility is channels 1-8
be set to trip common relay 1 while channels 9-16 trip relays
on an optional discrete relay PCB configured for Alarm 1 (see
Section
3.1.2).
•
Failsafe
controls relay activation for this common relay. Failsafe
ON causes the relay to de-energize during alarm conditions
HA71 Technical Manual
and energize when there is no alarm. Therefore a power failure
forces the relay contact to the alarm position. Note the common
Fault relay is always failsafe and may be monitored separately
to indicate loss of power conditions in many applications.
•
A1 and A2 Votes
equations that control common relay 1 & common relay 2.
Default settings for common relay 1 are A1 Votes = 01 and
A2 Votes = 00 which causes relay 1 to trip if any channel has
an A1 level alarm active. Default settings for common relay 2
are A1 Votes = 00 and A2 Votes = 01 which causes relay 2
to trip if any channel has an A2 level alarm active. Example: If
either default setting is modified such that A1 Votes = 02 and
A2 Votes = 01, then any two channels must have an A1 level
alarm active and any one channel must have an A2 level alarm
active to trip that relay.
CAutIoN
One of the A1's and the A2 could be on the same channel. These level alarms
must come from a channel included in the Group entry described above.
•
Turning
Acknowledge ON (not available on Alarm 1) allows
the common relay to be deactivated during alarm conditions
by an Alarm Reset. This is useful if an audible device is being
driven by the relay.
CAutIoN
All relays are rated at 5 Amp for 28 VDC and 250 ~VAC RESISTIVE
loads. Appropriate diode (DC loads) or MOV (AC loads) snubber
devices must be installed with inductive loads to prevent RFI noise
spikes. Relay wiring should be kept separate from low level signal
wiring.
2-9
allows creation of logical AND function
Revision 3 (04/08)
Advertisement
Table of Contents
