janitza RCM 202-AB Instruction manual

Dok.-Nr. 2.551.025.1.h 03/2020
Janitza electronics GmbH
Vor dem Polstück 6
D-35633 Lahnau, Germany
Support Tel. [phone]
E-Mail: [email protected]
www.janitza.de
www.janitza.de
RESIDUAL CURRENT MEASUREMENT DEVICE
RCM 202-AB
User manual and technical data

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Table of contents
1Information about using this user manual .......................................... 7
1.1General information ................................................................................. 7
1.2Abbreviations used .................................................................................. 7
1.3Notes on terminology............................................................................... 7
2Safety instructions ................................................................................ 8
2.1Symbols used .......................................................................................... 8
2.2General safety instructions ...................................................................... 8
3Purpose - Intended use ......................................................................... 9
4Scope of delivery................................................................................. 10
5Overview of the RCM 202-AB.............................................................. 10
5.1Device view ........................................................................................... 10
5.2Device dimensions................................................................................. 11
5.3Labeling ................................................................................................. 11
6Functions ............................................................................................. 12
6.1Basic functionality .................................................................................. 12
6.1.1Residual current monitoring principle..................................................... 12
6.1.2Current measurement transformer monitoring....................................... 13
6.2Parameterization options ....................................................................... 13
6.2.1Warning and alarm thresholds............................................................... 14
6.2.2Hysteresis.............................................................................................. 14
6.2.3Delay times............................................................................................ 15
6.3Extreme value storage........................................................................... 16
6.4Measured value memory/historical data ................................................ 16
6.5RS485 interface (Modbus)..................................................................... 17
6.6Digital outputs........................................................................................ 19
6.7Analog outputs (interfaces 4 … 20 mA).................................................. 19
7Connection assignment ...................................................................... 20
8Application example............................................................................ 22
8.1Application example RCM 202-AB in stand-alone mode ....................... 22
8.2Application example analog outputs (interface 4 … 20 mA) ................... 22
8.3Application example analog outputs and UMG 96RM-E........................ 23
8.4Application examples via Modbus (RS485 interface)............................. 24
9Assembly, commissioning and configuration .................................. 25
9.1Assembly (initial installation).................................................................. 25
9.2Commissioning ...................................................................................... 26
9.3Configuration (parameterization) ........................................................... 27

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10Display and operating elements......................................................... 27
10.1Display and keys.................................................................................... 27
10.2Meaning of the status LED .................................................................... 29
10.3Key functions ......................................................................................... 29
10.4Menu release......................................................................................... 29
11Operation.............................................................................................. 30
11.1Release and block of parameterization mode........................................ 30
11.2Operating steps for displaying and changing values in the menu.......... 31
11.3Operating steps for checking the monitoring function ............................ 33
12Configuration menu............................................................................. 34
12.1Menu: 1.Basic settings........................................................................... 36
12.1.1Menu item: LCD contrast ....................................................................... 36
12.1.2Menu item: Change date/time................................................................ 36
12.1.3Menu item: Language ............................................................................ 37
12.1.4Menu item: Parameter release .............................................................. 37
12.1.5Menu item: Change password ............................................................... 37
12.22.Channel parameter ............................................................................. 38
12.2.1Menu item: Channel active .................................................................... 39
12.2.2Menu item: Transformer type................................................................. 39
12.2.3Menu item: Monitoring active................................................................. 40
12.2.4Menu items: Warning th. I to warning th. I AC50 ................................... 40
12.2.5Menu items: Alarm th. I to alarm th. I AC50 ........................................... 41
12.2.6Menu item: Autom. reset........................................................................ 42
12.2.7Menu item: Hysteresis ........................................................................... 42
12.2.8Menu item: Response delay .................................................................. 42
12.2.9Menu item: Reset delay ......................................................................... 42
12.2.10Menu items: Digital output 1 and digital output 2 ................................... 43
12.2.11Menu item: Factor 4-20mA = 20 A......................................................... 43
12.3Menu: 3.Communication........................................................................ 44
12.3.1Menu item: Modbus active..................................................................... 44
12.3.2Menu item: Address............................................................................... 45
12.3.3Menu item: Baud rate ............................................................................ 45
12.4Menu: 4.Measured value memory ......................................................... 45
12.4.1Menu item: Record active ...................................................................... 45
12.4.2Menu item: Interval ................................................................................ 46
12.4.3Menu item: Delete record ...................................................................... 46
12.5Menu: 5.Min/max values........................................................................ 46
12.5.1Menu items: Channel 1 and channel 2 .................................................. 47
12.6Menu: 6.Functional test ......................................................................... 48
12.6.1Menu item: Test interval ........................................................................ 48

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12.6.2Menu item: last test................................................................................ 49
12.7Menu: 7.Service..................................................................................... 49
12.7.1Menu item: Transformer analysis........................................................... 50
12.7.2Menu item: Power frequency ................................................................. 51
12.7.3Menu item: Current value AC ................................................................ 51
12.8Menu: 8.Factory setting ......................................................................... 51
12.9Menu: 9.Information............................................................................... 52
12.10Menu: 10.Restart ................................................................................... 52
13Servicing .............................................................................................. 53
13.1Periodic inspection................................................................................. 53
13.2Maintenance .......................................................................................... 53
14Troubleshooting .................................................................................. 54
14.1Errors and their remediation .................................................................. 54
14.1.1The status LED is off ............................................................................. 55
14.1.2The status LED flashes green ............................................................... 55
14.1.3The status LED lights up green ............................................................. 55
14.1.4The status LED flashes yellow............................................................... 56
14.1.5The status LED flashes red ................................................................... 56
14.1.6The status LED lights up red ................................................................. 57
14.2Replacement of a defective RCM 202-AB ............................................. 58
14.2.1Removal of a defective RCM 202-AB .................................................... 58
14.2.2Installation of a new RCM 202-AB......................................................... 58
15Warranty and liability .......................................................................... 59
16Storage ................................................................................................. 59
17Disposal................................................................................................ 59
18Declaration of conformity ................................................................... 60
19Technical data...................................................................................... 60
19.1General technical data........................................................................... 60
19.2RCM 202-AB plug.................................................................................. 63
19.3Current measurement transformer......................................................... 63

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1 Information about using this user manual
1.1 General information
This user manual is intended exclusively for use by trained specialized electrotech-
nical personnel.
This user manual is a part of the product and makes reference to other devices from
Janitza electronics GmbH. Only the names of the respective device series are spec-
ified, but not all the associated types. Read this user manual before using the device.
Observe all safety requirements and warning notices. Failure to observe the instruc-
tions can lead to personal injury and/or damage to the product.
Keep the user manual through the entire service life of the product so it is available
for all users.
1.2 Abbreviations used
Abbrevia-
tion
Meaning
Modbus Communication protocol based on a master/slave architecture
DW Residual current transformer
H Hysteresis
I Δ Residual current
k S1 (transformer connection)
l S2 (transformer connection)
oAS Upper alarm threshold
oWS Upper warning threshold
t Time
t v Delay time for warning and alarm message
t vr Reset delay time for warning and alarm message
1.3 Notes on terminology
Work steps and processes are illustrated as follows:
“1. …”, even if there is only one work step, this format is used.
The standards indicated in the continuous text are written in abbreviated form, and
the complete designation can be found in chapter 19.1, from page 62.

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2 Safety instructions
2.1 Symbols used
WARNING
These symbols and the word “warning” are used when there is possible
danger to life and limb.
Symbols are also used in these instructions that refer directly to the source
of danger.
ATTENTION
This symbol and the word “attention” are used when there is the possibility
of property damage.
Observe the user manual!
This symbol and “Observe the user manual!” are used when reference must
be made to the user manual or other documentation.
NOTE
This symbols and the word “Note” are used to make reference to additional
information necessary for device use.
2.2 General safety instructions
The following safety instructions must be observed for work on and with the RCM
202-AB. Specific safety instructions are also listed in the respective chapters.
WARNING
All work necessary for the connection, assembly, commissioning and oper-
ation of the device may only be performed by well trained and instructed
specialist personnel. The specialist personnel must observe and comply
with the relevant applicable standards and directives for work on electrical
systems (e.g. DIN EN 50110 and ff./ directives and regulations of profes-
sional associations in Germany).

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ATTENTION
Use of the device requires sufficient knowledge of the product as well as
knowledge about the connected devices and systems. Changes to the pre-
set values and control commands influence the evaluation behavior of the
residual current measurement device. Therefore changes to the commis-
sioning settings as well as the replacement of devices may only be carried
out upon agreement with Janitza electronics GmbH!
Changes carried out are to be documented in the system documentation!
Observe the user manual!
This user manual as well as the device-specific user manuals for connected
devices must be strictly observed.
NOTE
The RCM 202-AB is supplied as a component of a residual and operating
current monitoring system. Upon commissioning/delivery of a monitoring
system, all system-specific settings and control commands for the RCM
202-AB shall be parameterized and documented by Janitza electronics
GmbH.
3 Purpose - Intended use
The RCM 202-AB is a two-channel residual current measurement device for the
measurement and monitoring of main distribution boards up to a maximum residual
current of 20 A.
With connected current measurement transformers (also current sensors), the RCM
202-AB is used for the measurement and monitoring of residual currents in TN and
TT systems (grounded AC systems).
With additional devices of the RCM series, display devices or devices for data cou-
pling to third-party systems, it forms a complete residual and operating current moni-
toring system. This monitoring system increases system and operational safety.
Faults or an increase in residual currents (usually creeping) are detected early on, for
example, thus allowing preventative maintenance. The external signal current circuits
used in the monitoring system shall be secondary current circuits.
Any use of the RCM 202-AB that differs from the description in this manual is consid-
ered improper use and may affect the protection provided by the device.

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4 Scope of delivery
The following components are part of the scope of delivery of an individual device:
1 x RCM 202-AB
1 set of plugs (on the device)
1 x user manual
Check the scope of delivery to ensure it is complete and immediately report any dam-
age or missing content to the manufacturer/sales partner.
5 Overview of the RCM 202-AB
5.1 Device view
Fig. 1: RCM 202-AB device view
1 Connection for 2 current measurement
transformers
2 Operating keys
3 Label with manufacturer, serial number
and item number
4 Supply voltage connection
5 Status LED
6 Display
7 Modbus termination switch
8 Modbus connection (RS485 interface)
9 Analog output connection (interface
4 … 20 mA)
10 Digital output connection
3
1
2
8 9 10
4
5
7
6

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5.2 Device dimensions
Fig. 2: Device dimensions in mm
5.3 Labeling
Various labels are applied on the RCM 202-AB with the following information:
Manufacturer
Serial number and item number
Technical data (short form)
CE mark

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6 Functions
6.1 Basic functionality
The main functions of the RCM 202-AB are:
Residual current measurement via a connected current measurement trans-
former (max. 2 current measurement transformers)
Transformer connection monitoring for wire breaks or short circuit per channel
Effective value measurement (true RMS)
Parallel measured value recording
Evaluation of fault currents (residual currents) type A and B according to IEC
62020
Detection of sinusoidal residual fault currents with frequencies up to 20 kHz
(type B+)
Measured value and extreme value storage with time stamp
Parameterizable alarm threshold for alarm message per channel
Parameterizable warning threshold (e.g. prewarning) for warning message per
channel
Parameterizable delay times:
Delay time for warning and alarm messages
Reset delay time for warning and alarm messages
Operating and error messages shown on the display
Communication via Modbus (RS485 interface/Modbus RTU)
Evaluation possibility with the help of the GridVis®monitoring system or a dis-
play and evaluation device
6.1.1 Residual current monitoring principle
The fault currents (residual currents) flowing to ground or other paths are recorded
via the connected current measurement transformers.
For example:
Outflow-related residual currents (consumers and systems)
Stray currents in TN-S systems (PEN and N conductors)

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ATTENTION
Do not route the PE conductor through the current measurement trans-
former!
Fig. 3: Simplified presentation of residual current measurement
6.1.2 Current measurement transformer monitoring
The RCM 202-AB evaluates currents from up to two current measurement transform-
ers at the same time. For each active channel, the RCM 202-AB continuously checks
the connected transformer for short circuit or wire breaks.
If a short circuit or wire
break occurs on the transformers, an error message is output on the display as well
as on the communication interfaces and the LED status flashes red.
6.2 Parameterization options
The parameters are described in the following sub-chapters, which can be changed
in the menu of the RCM 202-AB.

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6.2.1 Warning and alarm thresholds
Warning and alarm thresholds are parameterizable thresholds, which can be adapted
to the currents to be monitored. They can be adjusted separately for each channel.
When reaching these thresholds, warning or alarm messages are sent. The status
LED lights up yellow and channel-related text messages are shown on the display.
Example: Exceedance of warning and alarm thresholds
Parameterization: The digital output reacts to warning and alarm thresholds
(When the warning and alarm thresholds are exceeded, the
messages can be called up via Modbus after the delay time has
elapsed.)
Delay time tv> 0 s
Fig. 4: Response and warning thresholds and the resulting messages
6.2.2 Hysteresis
Alarm thresholds have a parameterizable hysteresis. They are defined separately for
each channel.
If the residual current, for example, exceeds the upper alarm threshold and then goes
back down, the alarm message is reset after the hysteresis is fallen below and the
parameterized reset delay time, if applicable, has passed.

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Example: Exceedance of warning and alarm thresholds with signal paths
Parameterization: The digital output reacts to alarm thresholds
(When the warning and alarm thresholds are exceeded, the
messages can be called up via Modbus after the delay time
has elapsed.)
Fig. 5: Evaluation of the set hysteresis for messages
6.2.3 Delay times
The following delay times can be set for residual current monitoring per channel:
Delay time for warning and alarm messages (t v )
Reset delay time for warning and alarm messages (t
vr )
Delay time for warning and alarm messages
Temporary threshold violations are not reported with parameterization of a delay time
for warning and alarm messages.
Messages are not taken into consideration during the parameterized delay time (t
v ).
They are only displayed and updated in Modbus if the current path still lies above the
warning or alarm threshold after the delay time has elapsed. Only then will the digital
output be set, if configured.
Reset delay time for warning and alarm messages
If there are no more messages, the RCM 202-AB resets the warning and alarm mes-
sages. The reset delay time (t vr ) for the warning and alarm messages can be param-
eterized and is needed to ignore brief fluctuations. When resetting a message, also
the digital output is reset.
If the current path goes down and falls below the hysteresis or the upper warning
threshold, the reset delay time (t
vr ) is activated.
During this time, the respective message remains active and the digital output is set.

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If the current path remains below the hysteresis after the reset delay time has
elapsed, the messages and the digital output are reset.
Example: Exceedance of warning and alarm thresholds with signal paths
Parameterization: The digital output reacts to alarm thresholds
(When the warning and alarm thresholds are exceeded, the messages can be called
up via Modbus after the delay time has elapsed.)
Delay time tv> 0 s
Reset delay time tvr > tv
Fig. 6: Effects of the delay times on messages
6.3 Extreme value storage
The RCM 202-AB stores the minimum and maximum values of residual current meas-
urement for each current channel with a time stamp.
The stored extreme values can be displayed by channel on the display and reset or
read out via Modbus.
6.4 Measured value memory/historical data
The RCM 202-AB files cyclical data sets of measured values in the internal memory.
This enables a later evaluation/report generation. The device-internal memory serves
as a buffer for the measured value database of the evaluation software, which con-
nects to the RCM 202-AB according to schedule (e.g. monthly) in order to read out
the data sets. During a connection, the data collected is read and sorted in the data-
base so that a complete history exists.

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The measured value memory is described circularly (circular buffer principle). If the
memory is full, the oldest data is overwritten. The period of time until the stored, his-
torical data is overwritten is dependent on the measurement interval (time base for
averaging). The measurement interval is set in the configuration menu.
Measurement interval for averaging Period of time available
60 s (1 min) 13 days
300 s (5 min) 65 days
600 s (10 min) 130 days
900 s (15 min) 195 days
1800 s (30 min) 390 days
3600 s (60 min) 780 days
Tab. 1: Available memory as a period of time depending on the measurement interval
The data set contains the following values, which are calculated as the mean value
over the set measurement interval:
Start and end time of the interval
Total current (residual current type B+)
Total current up to 2 kHz (residual current type B)
Direct current
Alternating current with frequencies up to 2 kHz (residual current type A)
Alternating current with frequencies up to 20 kHz
Fundamental oscillation
The measured value memory is not deleted automatically during operation. Data read
is not lost, except it is overwritten during the circulation of the memory. Therefore,
multiple databases (even on different computers) are kept current. When updating, a
database only reads out the data that has been newly stored since its last updating.
It is possible to manually delete the measured value memory via the configuration
menu.
6.5 RS485 interface (Modbus)
The RCM 202-AB has a Modbus interface (RS485) and works with the Modbus RTU
protocol as a slave. The device address 1 and the baud rate of 19200 baud are fac-
tory-set.
WARNING
The open ground connection of the RS485 interface may not be touched!
There is a risk of electric shock.

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Bus structure
The bus structure of the individual Modbus segments is basically linear. Up to 247
participants can be connected in a Modbus segment. If the data volume of the Mod-
bus participants is too large, the number of participants must be reduced. The cable
is closed with resistors at the start and end of a segment.
Fig. 7: simplified connection diagram of the RS485 interface (example)
Termination resistors
The D+/D-data line of a Modbus segment must always be provided with a termination
resistor of 120 Ωat the start and end to prevent reflections (termination).
Shielding
Twisted and shielded cable is always used for connections via the Modbus interface
(RS485). For a sufficient shielding effect, the shielding must be connected extensively
to one end of a cable with a grounded housing or cabinet parts.
Connection
The twisted wires of the cable must be connected to terminals “B+” and “A-”. In order
to equalize the potential differences between multiple RCM 202-AB, the ground ter-
minals of all devices on the bus must be connected together. The second twisted wire
pair of the bus cable is used for potential equalization. Both wires must be connected
to each ground terminal. The ground cable from both wires must be connected to one
end of the bus cable with PE.
WARNING
The power supply connection and the transformer connections of the RCM
202-AB may be switched on only after connecting the ground terminal and
grounding the ground cable.
There is a risk of electric shock.

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6.6 Digital outputs
ATTENTION
External signal current circuits must be secondary current circuits if the
RCM 202-AB is integrated in a monitoring system.
The digital outputs are not short-circuit proof.
Cables that are longer than 30 m must be installed shielded.
The RCM 202-AB has two transistor switching outputs. These digital outputs are elec-
trically isolated from the evaluation electronics via optocouplers.
The digital outputs switch direct current or alternating current loads.
The digital outputs switch loads independently of the polarity of the supply volt-
age.
6.7 Analog outputs (interfaces 4 … 20 mA)
The RCM 202-AB has two analogue outputs (interfaces 4 … 20 mA). The analogue
outputs output the effective value of the measured total current. Both analogue out-
puts require a separate power supply (DC 12 … 24 V). In the configuration menu of
the RCM 202-AB, the measuring range (total current) can be scaled. In systems with
low total currents, this makes it possible for the measured total current to be evaluated
in a more precise manner. The message “overflow” is displayed when the set meas-
uring range (total current) is exceeded and can be called up via Modbus.
Set value “Factor 4 … 20 mA”: 5 A 10 A 15 A 20 A
Measured total current Output value of the analog output
0.00 A 4.0 mA 4.0 mA 4.0 mA 4.0 mA
2.45 A 11.8 mA 7.9 mA 6.6 mA 6.0 mA
2.50 A 12.0 mA 8.0 mA 6.7 mA 6.0 mA
2.60 A 12.3 mA 8.2 mA 6.8 mA 6.1 mA
5 A 20 mA 12 mA 9.3 mA 8.0 mA
10 A Error 20.0 mA 14.7 mA 12.0 mA
14 A Error 18.9 mA 15.2 mA
15 A 20.0 mA 16.0 mA
16 A Error 16.8 mA
20 A 20.0 mA
Tab. 2: Example of the output value of the analog output depending on the set factors
and measures total current

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7 Connection assignment
Fig. 8: Circuit diagram of the RCM 202-AB