1.0
INTRODUCTION
These instructions refer to the above model. Supplementary
sheets are attached if the unit has special options or features.
For detailed specifications, refer to the Data Bulletin. All
ADTECH instruments are factory calibrated and supplied
with a label detailing the calibration. Adjustments are normally
not necessary. A simple check should be performed to
verify calibration before installation to ensure that it matches
the field requirement.
2.0
GENERAL DESCRIPTION
The ADTECH DVA 112 is a deviation alarm that accepts two
process input signals like 1-5 vdc or 4-20 ma de and provide
relay contact output(s) based on deviation limits.
The DVA 112 deviation alarm provides one SPOT output per
relay as standard. DPDT output is optionally available and
requires the "Wide Line" enclosure. The alarm operates
when deviation between the two inputs exceeds a preset set
value.
Relay K1 switches when input A just increases over (input B
+ Deviation). Relay K2 switches when input B just increases
over (Input A+ Deviation). The above is true for high trip. For
low trip, the condition, "just increase over" changes to "just
decreases below."
The alarm may be a Hi or Low alarm. Internal jumpers
determine the proper relay(s) action.
The relay coil may be power fail safe (i.e.) energized for
normal conditions or NON-power fail safe (i.e.) energizes on
alarm conditions.
Unless otherwise specified the DVA 112 alarm is set as
Hi NFS (High Non-Failsafe).
Red/Green LED indicator(s) for alarm condition are provided.
Green indicates normal condition and red indicates alarm
condition.
Power Option P-1 Non-Isolated 24 vdc provides negative
input signal and negative DC power common rail connection.
3.0
INSTALLATION
The instrument is supplied in a general purpose enclosure
as standard. NEMA4, 7 or 12 and plug in chassis enclosures
are optionally available.
Installation area/location must
agree with the supplied instruments including operating
temperature and ambient conditions.
Mounting
Refer to the appropriate outline drawing for mounting and
clearance dimensions. The instrument is surface mounted
with two #10-32 screws on 8.00 inch centers.
Electrical Connections
The wire used to connect the instrument to the control
system
should be a twisted pair(s) and sized
lnpuUOutput,
DVA 112
DC Current/Voltage Deviation Alarms
Instruction Manual
according to normal practice. Shielded cable is not normally
necessary (if used, the shield must be grounded at the input
negative of the ADTECH instrument and left floating at the
sensor).
A 12 position barrier terminal block with #6-32 screws and
3/8" spacing is provided for 1/0 and power connection.
A housing ground terminal marked G is also provided.
Controls
Multiturn trip set control is provided to set the deviation trip
point level. Adjustable dead band deviation control(s) are
also provided.
If optional calibrated dial for trip set or
adjustable dead band control(s) is supplied, they are normally
mounted in the "Wide Line" enclosure.
The multiturn control(s) is accessible through the instrument
front panel and is clearly marked for ease of use.
4.0
MAINTENANCE
These instruments are electronic except for the relay(s)
output(s) and require no maintenance except for periodic
cleaning and calibration verification. The standard relay is
rated by the manufacturer for 500,000 1 O amp operations at
30 vdc and 2x10
7
mechanical operations. Relay output(s)
should be verified at user established time intervals. If the
unit appears to be mis-operating it should be checked in
place per section 6.0 or removed for a bench check per
DVA 112
A , B ( -)
AIN (+)
BIN(+)
t
24 V+
*
K-1
K-2 t
�
N (- FOR DC)
AC
L (+ FOR DC)
rFP
NOTE:
K1 TRIPS WHEN A= B + DEV.
K2 TRIPS WHEN B =A+ DEV.
-1-
DVA 112
DPDTOUTPUT
OPTION O 34
*
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(D
1A f
©
®
K
0
®
©
©
2A k
®
©
K
f
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©
*
®
0
K1B
©
(T B2)
@
®
@
®
@
K2B
k
®
(TB2)
....r::-
@
®
®
DVA-112-B
6/2000
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