AMALGAMATED INSTRUMENT RM3-AV Guida
RM3-AV
AC Volts Transmitter
(True RMS)
Operation and
Instruction Manual
Introduction
This manual covers the installation and operation of the RM3-AV AC volts true RMS transmitter . The RM3
accepts inputs in the ranges 1.5V, 15V, 150V or 250V RMS (link selectable) and produces a loop powered
4-20mA output which is zero and span adjustable. For voltages above 250V RMS an external voltage
transformer can be used to lower the input voltage to a suitable range. A DC link selection is also provided,
with the DC link in any DC component of the AC waveform will be measured. With the DC link out only the AC
components of the waveform will be measured. The RM3-AV is available in one, two, three or four channel
versions. An optional inbuilt loop supply board is available for use with one or two channel models.
Mechanical Installation
The RM3 clips onto a standard 35mm DIN rail as shown below.
Dimensions
Page 2 of 8 RM3AVMAN-1.1-1
Earth bolt may be slid in from the rear
of the instrument (top or bottom)
44mm
91mm
135mm
Electrical Installation
Plug in type screw connector terminal blocks are provided for ease of installation. The terminal blocks allow
for wires of up to 2.5mm² to be fitted. Connect the wires to the appropriate terminals as indicated in the
diagram below. For EMC compliance the case of the instrument should be earthed via the case earth lug.
The diagram below shows a 4 channel version.
Page 3 of 8 RM3AVMAN-1.1-1
4
4
2
3
4
S
Z
Z
O/P
S
Z
S
S
Z
3
2
1
3
1
1
1
2
2
3
44-20mA
Output
4-20mA
Output
4-20mA
Output
4-20mA
Output
+
+
++
-
-
-
-
AC Volts Input
AC Volts Input
AC Volts Input
AC Volts Input
O/P
O/P O/P Channel 1
Channel 2
Channel 3
Channel 4
Earth lug - can be located at the top or
bottom of the case as re
q
uired
RM3-AV-LPI-4 SERIAL No :
4 CHANNELS
1 AC VOLTS INPUT
2 AC VOLTS INPUT
3 4-20mA OUTPUT +VE
4 4-20mA OUTPUT -VE
Instrument data label - 4 channel example
Typical interconnection diagram
Example 1 - connection to PLC using PLC supplied 24VDC to power the output loop. External voltage
transformer used to step down input voltage.
Example 2 - connection to a remote display using external 24VDC supply to power the output loop.
Example 3 - connection to a remote display using the optional internal RM3-PS dual 24VDC output power
supply to power the output loop.
Page 4 of 8 RM3AVMAN-1.1-1
24VDC
IN+
IN-
VOLTAGE
TRANSFORMER
RM3-AV-LPI PLC
1
+3
2-4
AC Volts 4-20mA
+
-
24VDC
IN+
IN-
RM3-AV-LPI
AC Volts Remote display
1
+3
2-4
4-20mA
IN+
+
+
IN-
RM3-AV-LPI
Optional inbuilt
RM3-PS power supply
AC Volts
Remote display
1
+3
A
1
Earth
Neutral
Active
B
2
C
3
424VDC
24VDC (not used)
2
-4
-
-
4-20mA
Input range links
To gain access to the input range link settings remove the four front bezel screws and the single screw which
passes through the side of the instrument then slide out the bezel and circuit boards. If more than one board
is fitted they are joined via a single multi way connector and can be pulled apart.
Page 5 of 8 RM3AVMAN-1.1-1
300V 300V
300V 300V 300V 300V 300V
150V 150V
150V 150V 150V 150V 150V
15V 15V
15V 15V 15V 15V 15V
DC DC
DC DC DC DC DC
1.5V 1.5V
1.5V 1.5V 1.5V 1.5V 1.5V
CIRCUIT BOARD
INPUT LINK SETTINGS
EXAMPLES - SEE TABLE
FOR OTHER INPUT SETTINGS
250V Range selected
(note: range not 300 as marked)
150V Range selected
15V Range selected
1.5V Range selected
150V Range selected
with DC component link
Zero and Span Adjustment
Each channel of the RM3-AV is adjustable for zero and span. Adjustment is via front panel potentiometer.
The procedure for zero and span adjustment is given below.
1. Ensure that the input links have been set for the correct input type.
2. Using a simulator live input set the input to the level required for a 4mA output.
3. Measure the output using a milli-ammeter and adjust the zero potentiometer until the output is 4mA.
4. Using a simulator live input set the input to the level required for a 20mA output.
5. Adjust the span potentiometer until the meter reading is 20mA.
6. Repeat steps 2 to 5 until the output at both 4 and 20mA are correct to the required tolerance.
Note: The RM3-AV is able to be spanned over a part of its input range if required. A table giving span range
for each input is given below.
Maximum
Input Range
Typical Zero
Adjustment Range
Typical Span
Adjustment Range
0 to 1.5V 0 to 0.075V 1.2 to 1.8V
0 to 15V 0 to 0.75V 12 to 18V
0 to 150V 0 to 7.5V 120 to 180V
0 to 250V 0 to 15V 240 to 250V
An example of a typical zero and span adjustment measurement setup is shown below.
Page 6 of 8 RM3AVMAN-1.1-1
4
4
2
3
4
O/P
3
2
1
3
1
1
1
2
2
3
4
O/P
O/P O/P
+
+
-
-
AC
Voltage source
Milli-
ammeter
24V
Loop Supply
S
Z
Z
S
Z
S
S
Z
Specifications
TECHNICAL SPECIFICATIONS
Input: Link selectable 0-1.5, 0-15, 0-150 or 0-250VAC with DC link to allow DC
component of the waveform to be taken into account if required.
Output: 4-20mA (true RMS measurement)
Supply: Loop powered. Loop supply voltage required 9 to 34VDC
Accuracy: 0.5% of full scale (pure sinewave input)
Linearity: Better than 0.5%
Response Time: <0.5 sec to 1%
Response time is specified over the stated RMS input level with the
input signal increasing from zero. Response time will be greater for
decreasing amplitude signals
Protection: Reverse polarity output protection
Isolation: 2kV between channels and input/output (for 60 seconds).
Loop Supply: 9 to 34VDC
Maximum Load: RL= Supply (V) - 9 Ohms
0.02
Load Effects: Effect on accuracy of changing load resistance is no greater than 0.1%
of full scale
Ambient temp: 0 to 60oC
Humidity: 5 to 95% non condensing
PHYSICAL CHARACTERISTICS
Case size: 44mm x 91mm x 120mm
Mounting: 35mm DIN Rail mount (EN50022)
Connections: Plug in screw terminals
(max 2.5mm2wire)
Weight: 250 gms for one channel
300 gms for two channels
350 gms for three channels
400 gms for four channels
Page 7 of 8 RM3AVMAN-1.1-1
Guarantee & Service
The product supplied with this manual is guaranteed against faulty workmanship for a period of 2
years from the date of dispatch.
Our obligation assumed under this guarantee is limited to the replacement of parts which, by our
examination, are proved to be defective and have not been misused, carelessly handled, defaced or
damaged due to incorrect installation. This guarantee is VOID where the unit has been opened, tampered
with or if repairs have been made or attempted by anyone except an authorised representative of the
manufacturing company.
Products for attention under guarantee (unless otherwise agreed) must be returned to the
manufacturer freight paid and, if accepted for free repair, will be returned to the customer’s address in
Australia free of charge.
When returning the product for service or repair a full description of the fault and the mode of
operation used when the product failed must be given.
In any event the manufacturer has no other obligation or liability beyond replacement or repair of
this product.
Modifications may be made to any existing or future models of the unit as it may deem necessary
without incurring any obligation to incorporate such modifications in units previously sold or to which this
guarantee may relate.
Page 8 of 8 RM3AVMAN-1.1-1
This document is the property of
the instrument manufacturer
and may not be reproduced in whole or part without the
written consent of the manufacturer.
This product is designed and manufactured in Australia.
Indice
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