Electrical Installation
ELECTRICAL INSTALLATION
Power
Use the following guidelines when selecting a power source:
• Use an 8…28V DC power supply The specific connection depends on which output is option is used
• Use clean electrical line power
• Do not operate this unit on circuits with noisy components such as fluorescent lights, relays, compressors or variable frequency drives
• Use linear power supplies
N OTEE:
The power and output connections share a common ground
Wiring
4…20 mA Loop
Connect a twisted pair wire (not provided) to the terminals of the transmitter marked 8…28V DC and Output Do not connect the shield to the transmitter if the twisted pair wire is shielded The shield should be grounded at the receiver only
See
Figure 6
The transmitter is reverse-polarity protected
8…28V DC
Output
Programming
4…20 mA
POWER
SUPPLY
8…28V DC
RECEIVER
Load
Figure 6: Loop connection with single load
The receiving equipment must accept industry standard true two-wire or loop powered 4…20 mA process transmitter inputs
The power can either be supplied by the receiving equipment or an external power supply that supplies 24V DC an 30 mA
See
Figure 6
for the wiring setup using an external power source and
Figure 7
using the receiver as the power source Several
receivers may be connected in a series as shown in
Figure 7
, but only one should provide power, and all should have isolated inputs
8…28V DC
Output
Programming
4...20 mA
RECEIVER RECEIVER
RECEIVER/POWER SUPPLY
Additional Loads
Figure 7: Loop connection with multiple loads
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Electrical Installation
The voltage provided by the receiver must be within the limits shown in
Figure 8
1100
1000
900
800
700
600
500
400
300
200
100
Supply Voltage – 8V DC
0.02
= Maximum Loop Resistance
Operate in the
Shaded Region
8
10 12 14 16 18 20 22
Supply Voltage (V DC)
Figure 8: Supply voltage chart
24 26 28
To use this figure:
1 Add the resistance of all the receivers, indicators and the wire in the loop If the wire resistance is unknown, use a value of
50 ohm for a twisted wire of 1000 feet or less with a gauge of #22 awg or heavier
2 Find the total load (in ohms) on the left side of the chart in
Figure 8
and follow that value horizontally until it intersects with the shaded area
3 From the intersection point look straight down to where a vertical line would intersect the voltage scale This is the minimum voltage needed for the transmitter to operate properly under the specific load conditions
Example
After checking the specification for all the loads in an application the total amounted to 800 ohms Following the 800 ohm line to the right, the intersection point is about 3/4 of the way across the chart in
Figure 9
A vertical line through the intersection point crosses the voltage axis at about 24V DC, so with a load of 800 ohms a standard
24 volt power supply would be used
600
500
400
300
200
100
1100
1000
900
800
700
8
10
Supply Voltage - 8V DC
0.02
= Maximum Loop Resistance
Operate in the
Shaded Region
26 28 12 14 16 18 20 22
Supply Voltage (V DC)
Figure 9: Supply voltage example
24
0…5V DC Output
Page 12
8…28V DC
Output
Ground
Programming
+8-28 VDC
Output
Gnd
Digital Display
0…5V DC
8…28V DC
POWER
SUPPLY
Figure 10: 0…5V DC wiring
VRX-UM-00371-EN-02 August 2015
Electrical Installation
Pulse Output
8…28V DC
POWER
SUPPLY
Counter
Pulse
Output
Programming
Output
Gnd
8…28V DC
Output
Ground
Figure 11: Pulse output wiring
Three-Pin Connection Option
An optional three-pin connection is available for when the transmitter/meter combination is mounted remotely from the power source/receiver The mating connector is P N RF8687000
White
4…20 mA Input
8…28V DC
Output
+8-28 VDC
Output
Gnd
Meter
Electronics
Black
– 4…20 mA Input
4…20 mA Input
+ -
8…28V DC
Power Supply
P.N. RF8687000 Connector
– 4…20 mA Input
+ mA
Ammeter
-
Figure 12: Remote connection loop power
Black
- Supply Green
Ground
+8-28 VDC
Output
Gnd
8…28V DC
Output
Ground
White
Output
Meter
Electronics
August 2015
Green
Ground
Black
+V
+ -
8…28V DC
Power Supply
P.N. RF8687000 Connector
White
Output
Counter
Figure 13: Remote connection 0…5V DC or pulse output
VRX-UM-00371-EN-02 Page 13