Honeywell HA71, Technical Manual

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HA71 Digital Gas Controller
Revision 3 (04/08)
HA71 Technical Manual 2-4
The
•
ON DELAY / OFF DELAY entries allow ON and OFF time
delays affecting how long the setpoint must be surpassed before
an alarm event transition occurs. ON delays are limited to 10
seconds while OFF delays may be as long as 120 minutes.
Delays are useful in many applications to prevent nuisance
alarms and unwanted cycling into and out of alarm conditions.
The
•
HORN ON entry allows linking this alarm to the common
horn relay. NO causes the alarm to have no effect upon the horn
relay. Entering YES causes this alarm to turn the horn relay on
steady, or, to pulse it depending upon horn configuration in the
system menu (see
Section 2.3.1 ).
Discrete LED indicators on the front panel indicate the status of each
alarm and relay. Any new alarm event causes the associated LED to
flash until Alarm Reset occurs causing an acknowledged steady on
condition. Operators should recognize new alarms by a flashing LED.
Alarm Reset also acknowledges, or deactivates, the horn relay until
another new alarm occurs.
CAutIoN
All relays are rated at 5 Amp for 28 VDC and 250 ~VAC RESISTIVE loads.
IMPORTANT: 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.
2.2.3 Alarm 3 / Fault Alarm Menu
The discrete channel alarms identified as Alarm 3/Fault may be
configured either as a 3rd level alarm, or, as a Fault alarm indicating
the input is out of range in the negative direction. When used as a
level alarm, features such as on / off delays, latching, and trip direction
are also available. It is important to understand that though discrete
channel alarms (LED’s & optional discrete relays) may be set as Alarm
3 level alarms, the common relay for this group is always a Fault alarm.
The fault out of range threshold for the channel is the most recent Fault
trip point entered prior to changing the menu to Alarm 3. The following
example describes how to configure both the Fault out of range and
Alarm 3 level trip points for a channel.
Example: If the common Fault relay must trip as the input falls below
negative 10% of full scale, and, the discrete alarms trip as the input
exceeds a level, then the –10% Fault setpoint must be entered first.
Toggle the TYPE menu entry to FAULT and enter –10.00% into the
setpoint entry. Next, toggle the menu back to LEVEL and enter the
desired Alarm 3 level setpoint. The Fault value is retained in memory
even though it no longer appears on the menu.
Channel XX
FAULT Setup
Setpoint -5.000
Type FAULT
Alarm 3 / Fault menu
If for A3 level
Channel XX
ALARM 3 Setup
Setpoint 60.00
Latching
Trip On
On Delay
Off Delay
NO
HIGH
00s
00m
Type LEVEL
Entry menu
Channel XX
Measurement Name
Alarm 1
Alarm 2
Alarm 3
Data From
Calibrate
Linearize
Configure
EDIT
NEXT
Figure 2-4. Alarm / Fault Alarm Menu
2.2.4 Data From? Menu to Set Input Source
Each channel may be independently configured to accept input data
from the Modbus RS-485 master port or, from an analog input card
attached to the I
2
C bus (see Figure 2-5). EDIT toggles the Data From:
entry between Modbus RTU, Analog, Analog with Local Cal or Sensor
Direct. There are eight different Modbus possibilities available to
accommodate the binary resolution and format of the input data (see
Figure 2-5). Each Modbus menu selection also requests the RTU # and
the Alias register # location of the data to be retrieved from the RTU.
Alias register numbers define the location of the variable representing
the input value and must be obtained from the manufacturer of the
Modbus RTU device.