Installation/ Operation
15.
POWER
15.1
The
DATAFLOW RTU
small enclosure (S) may be purchased with the delete internal power (D) option. The
RTU power source is a user-provided external power supply meeting the following criteria:
•
Between IO VDC and 16 VDC with 12 VDC nominal;
•
Has less than IV peak-to-peak of ripple;
•
Provides 1.5
A
with the transmitter in low power setting;
•
Provides 2.5 A with the transmitter in high power setting.
15.1.1 Connect the positive side of the power supply to JI05 pin 6. Connect the negative side of the power supply to
JI05 pin. The negative side of the power supply is considered to be GROUND and is the REFERENCE to
which all inputs, outputs and measurements are to be made. GROUND is connected to the enclosure.
15.2
You can purchase the
DATAFLOW RTU
with an eight-cell internal battery holder (power option I). In this
option, internal AA batteries are used as the power source.
CAUTION:
When installing the batteries, be sure to match polarities of the batteries with the
battery holder. Not matching polarities can damage the RTU.
15.2.1 The negative side of the battery assembly is considered to be GROUND and is the REFERENCE by which all
inputs, outputs, and measurements are to be made. GROUND is connected to the case.
15.2.2 The battery voltage appears at pin 8 of JI 05 pin 8, and is not connected directly to the input power of the RTU
control board. With jumper PJI06 installed, the battery is jumpered to the input power. With jumper PJI06 not
installed, an external connection is required between pin 6 and 7, which allows the user to install an external
ON/OFF switch to the RTU while using internal power.
15.3
JJ0l pin 5 is connected to the RTU power source, and JJ0I pin 6 is connected to GROlil','D. This power supply
provides excitation voltage to external equipment with maximum current draw of .25 A.
15.4
Fuse FI 01 (X3.2 - YO.!) is a 40-gauge tinned wire designed to open at 2.5A. If this fuse is destroyed, replace it
with nothing larger than 40-gauge wire.
15.5
Optional Internal Battery Back-up (Refer to 11.1.3 for the appropriate pin numbers.)
Either of the following two options may be used as an optional internal battery back-up:
a.
A two 4-cell battery pack (RITRON Part No. RTU-BATNICD),
OR
b.
An 8-cell AA battery holder (RITRON Part No. RTU-BA THOLD).
15.5.1 Connect the battery as shown in Figure A6:
CR1
13.1
CR2
RTU 7-PIN
CONNECTOR
,..-<----'--,-=.:;.;_-
7
I
ORN
i
Vsource
------C
-,i'--4>----------"'-+-'-"=--
v.
6
I
RED
5
I
BRN
GND----------------,----
NOTE: CR1 and CR2 are to be 1N5817.
B+
VI
GND
Figure A6 - Battery Connection Wiring Diagram.
15.5.2 The following equations define the values required for RI.
RI = (Vsource - Vdiode - Vbattfull) / Icharge
PR!= (Vsource - Vdiode - Vbattempty)
2
/ Rl
WHERE: RI is the value of RI in Ohms --
V source is the input voltage to the RTU.
Vdiode is the voltage drop of the diode (CR!).
Vbatfull is the fully charged voltage of the internal battery.
!charge is the charge current to the battery.
PR! is the power rating of RI in Watts.
Vbattempty is the empty voltage of the internal battery.
( A-14)
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