Endress+Hauser RMS621 User manual

BA127R/09/en/08.04
510 04788
Software
Version 2.0
Operating manual
RMS 621
Energy manager

RMS 621
2Endress+Hauser
Overview
Using the following overview the unit can be swiftly and easily commissioned:
Short form operating instructions
"
Caution!
The information contained in these Operating Instructions serves as a guide to help you commission
your device easily, i.e. the most important settings are listed here but special functions (e.g. Tables,
Corrections etc.) are not.
Configuring a measurement - Set-up example
Example 1: Steam heat (or steam mass)
Sensors: DPO10 (orifice), Cerabar T, TR 10
1. Connect device to the power source (terminal L/L+, 220 V)
2. Press any key →Menu →Setup (all parameters)
3. Basic set-up
Date-time (set up date and time) ÆZ
4. Flow inputs (flow 1)
Flow meter: Differential pressure
Diff. device: Orifice corner tap
Signal: 4 to20 mA
Curve: linear (also set up linear curve at the DP transmitter)
Terminals: Select A10 and connect DP transmitter to terminals: A10(-)/82(+) (because of
passive signal)
Set up start- and end-value (in mbar!)
Tube data: enter internal tube diameter and diameter ratio (ß) as found on the maufacturers
data sheet.
"
Caution!
If tube data is not known, for flow meter: operating volume
Curve: linear (set up square rooted curve on the DP transmitter)
Set up start- and end-values einstellen (m
3
/h)
5. Pressure input (Pressure 1)
Signal type: e.g. 4 to 20 mA
Terminals: Select A110 and connect Cerabar T to terminals: A110(-)/A83(+) (passive signal)
Type: Select absolute (-pressure measurement) or relative (-pressure measurement)
Set up start- and end-values of the presuure transmitter Æ
Z
Safety notes Page 8
Æ
Installation Page 11
Æ
Electrical connections Page 13
Æ
Human interface Page 22
Æ
Commissioning Page 29
Quick SET-UP - Fast entry into unit set-up for standard operation.
Unit set-up - explanation and application of all unit functions with the relevant values
and settings.
Application examples - Unit set-up in connection with an application example.

RMS 621
Endress+Hauser 3
6. Temperature inputs (temp. 1.1)
Signal type: Pt100
Sensor type: 3- or 4-wire
Select terminals E1-6 and connect Pt100 Æ
Z
Æ
Z
.
7. Application
Application 1: Steam heat
Steam type: super heated steam
Allocate flow 1, pressure 1 and temp. 1.1 to the steam measurement.
8. Display
Group 1
Display mask: 4 values
Value 1 (...4): flow 1, temp. 1.1, pressure 1 and density 1 Æ
Z
Group 2: select to above system e.g. mass flow 1, heat flow 1, mass sum 1.
9. Exit set-up
Exit set-up by operating ESC
Z
a number of times and acknowledging with
F
.
Display
By operating any key you can enter the main menu and select the required group including all the
relative display values: Display -> Group -> Group 1. All can also be displayed in an automatic scroll
function: Setup -> Display -> Scrolled display (scroll using the arrow under group 6).
If a fault occurs the display automatically changes colour (blue/red). Detailed fault finding and
elimination can be found in the relative chapter of these operating instructions.
Example 2: Liquid heat difference
Sensors: 2 x TST90, Promag 50
1. Connect device to the power source (terminal L/L+, 220 V)
2. Press any key →Menu →Setup (all parameters)
3. Basic set-up
Date-time (set up date and time) Æ
Z
4. Flow input (flow 1)
Flow meter: Operating volume
Signal type: 4 to20 mA
Terminals: select A10 and connect the Prowirl to terminals: A10(+)/11(-) (active signal)
Set up start- and end-values
5. Temperature inputs (temp. 1.1 and temp. 1.2)
Signal type: Pt100
Sensor type: 3- or 4-wire
Terminals: select E1-6 and connect TST90 (temp. 1.1) Æ
Z
Terminals: selectE3-8 and connectTST90 (temp. 1.2)Æ
Z
Æ
Z
Fig. 1: Temperature sensor connection, e.g. to input 1 (Slot E I)
Pos. 1: 4-wire input
Pos. 2: 3-wire input
Pos. 3: 3-wire input e.g. optional
temp. expansion card (Slot B I)

RMS 621
4Endress+Hauser
6. Applications
Application 1: Water heat differential
Operating mode: Heating
Select "Flow 1"
Installation point: Cold (means return)
Allocate temperature sensors 1.1 and 1.2 to heat and cooling section.
7. Display
Group 1
Display mask: 4 values
Value 1 (...4): Flow 1, temp. 1.1, temp. 1.2 and density Æ
Z
Group 2: select to above system e.g. mass flow 1, heat flow 1, mass sum 1 etc.
8. Exit set-up
Exit set-up by operating ESC
Z
a number of times and acknowledging with
F
.
Display
By operating any key you can enter the main menu and select the required group including all the
relative display values: Display -> Group -> Group 1. All can also be displayed in an automatic scroll
function: Setup -> Display -> Scrolled display (scroll using the arrow under group 6).
If a fault occurs the display automatically changes colour (blue/red). Detailed fault finding and
elimination can be found in the relative chapter of these operating instructions.
An example of steam mass measurement using a Prowirl 77 can be found in the appendix of this
operating manual.
Application basic set-up
The values shown are only an indication in order to simplify the commissioning of the device, this
means that only the most necessary settings are shown. Special functions (e.g. tables, corrections,
etc.) are not shown.
Water applications
Input values: Flow, temperature 1, (temperature 2)
Fig. 2: Temperature sensor connection, e.g. to input 1 (Slot E I)
Pos. 1: 4-wire input
Pos. 2: 3-wire input
Pos. 3: 3-wire input e.g. optional
temp. expansion card (Slot B I)
Flow
Pulse/PFM (e.g. ProWirl) Analogue (e.g. Promag) Differential pressure (e.g. Orifice)
Flow input Flow input Flow input
Flow meter: Operating volume Flow meter: Operating volume Differential pressure/Orifice/water
Terminals:
– Flow meter with active signal connect to e.g. terminals A10(+)/11(-).
– Flow meter with passive signal select e.g. terminals A10 and connect to terminals A10(-)/82(+).
k factor Start/end value (m
3
/h) Start/end value (mbar)

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!Note!
Only one temperature available for liquid heat quantity. A direction signal teriminal is required on
changing flow direction (bi-directional operating mode).
Steam application
Input values: Flow, pressure, temperature 1, (temperature 2)
!Note!
2 temperature sensors are required for steam diferential applications.
Pressure
Select signal type and terminals and then connect sensor (see example).
Type: Relative- or absolute-pressure? Enter start- and end-values.
Temperature
Select signal type and connect sensor(s) (see example). 2 temperature sensors are required for heat differential measurements.
Application
Application: e.g. Water- heat differential
Operating mode: e.g. heating (this means inflow warm, return cold)
Allocate installation point for flow measurement sensor (warm/cold)
Allocate temperature sensors
Flow
Pulse/PFM (e.g. ProWirl) Analogue (e.g. Promag) Differential pressure (e.g. Orifice)
Flow
Pulse/PFM (e. g. Prowirl) Analogue (e. g. Prowirl) Differential pressure (e. g. Orifice)
Flow input Flow input Flow input
Flow meter: Operating volume Flow meter: Operating volume Differential pressure/Orifice.../Gas
Terminals:
– Flow meter with active signal connect to e.g. terminals A10(+)/11(-).
– Flow meter with passive signal select e.g. terminals A10 and connect to terminals A10(-)/82(+).
k factor Start/end value (m
3
/h) Start/end value (mbar)
Pressure
Select signal type and terminals and then connect sensor (see example).
Type: Relative- or absolute-pressure? Enter start- and end-values.
Temperature
Select signal type and connect sensor(s) (see example). 2 temperature sensors are required for heat differential measurements.
Application
Application (1);
Application: e.g. steam mass
Steam type: e.g. superheated
Allocate sensors for flow, pressure and temperature measurement

RMS 621
6Endress+Hauser

7
Table of contents
1 Safety notes . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.1 Correct use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2 Installation, commissioning and operation . . . . . . . . 8
1.3 Operational safety . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.4 Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.5 Safety characters and symbols . . . . . . . . . . . . . . . . . 9
2 Identification . . . . . . . . . . . . . . . . . . . . . . . 10
2.1 Unit identification . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2 Complete delivery . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Certificates and approvals . . . . . . . . . . . . . . . . . . . 10
3 Mechanical installation . . . . . . . . . . . . . . 11
3.1 Installation conditions . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3 Installation control . . . . . . . . . . . . . . . . . . . . . . . . 12
4 Electrical installation . . . . . . . . . . . . . . . . 13
4.1 Electrical connection overview . . . . . . . . . . . . . . . 13
4.2 Connecting measurement sensors . . . . . . . . . . . . . 14
4.3 Connection control . . . . . . . . . . . . . . . . . . . . . . . . 22
5Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1 Operation at a glance . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 Human interface . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4 Error message display . . . . . . . . . . . . . . . . . . . . . . 27
5.5 Communication . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6 Commissioning . . . . . . . . . . . . . . . . . . . . . 29
6.1 Installation control . . . . . . . . . . . . . . . . . . . . . . . . 29
6.2 Switch unit on . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.3 Quick Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.4 Unit set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.5 Customer-specific applications . . . . . . . . . . . . . . . . 50
7 Maintenance . . . . . . . . . . . . . . . . . . . . . . . 51
8Accessories
. . . . . . . . . . . . . . . . . . . . . . . . . 51
9 Fault-finding
. . . . . . . . . . . . . . . . . . . . . . . . 51
9.1 Troubleshooting instructions . . . . . . . . . . . . . . . . . 51
9.2 System error messages . . . . . . . . . . . . . . . . . . . . . . 51
9.3 Process error messages . . . . . . . . . . . . . . . . . . . . . 52
9.4 Spare parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.5 Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.6 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10 Technical data . . . . . . . . . . . . . . . . . . . . . . 57
11 Appendix
. . . . . . . . . . . . . . . . . . . . . . . . . . 65
11.1 Definition of important system engineering units . . 65
11.2 Configuration flow measurement . . . . . . . . . . . . . . 65
11.3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Index

1 Safety notes RMS 621
8Endress+Hauser
1Safetynotes
Safe operation of the energy manager can only be ensured if all hints and warnings in this installation
and operating manual are thorougly read and followed.
1.1 Correct use
The RMS 621 energy manager is a unit for monitoring energy and flows in water and steam
applications. It can be used in both heating and cooling systems. A large variety of different flow
sensors, temperature and pressure sensors can be connected to the unit. The energy manager
accepts the current/PFM/pulse or temperature signals from the individual sensors and from these
calculates the liquid and energy values:
–Volumeandmass
– Heat flow or energy
– Heat energy differential
all using the international calculation standard IAPWS-IF 97.
– The unit is classified as additional equipment and may not be used in a hazardous area.
– The manufacturer cannot take responsibility for any damage caused by misuse of the unit. It is not
permitted to make any changes or reconstruction to the unit.
– The energy manager has been designed for use in an industrial environment and may only be used
in an appropriately installed condition.
1.2 Installation, commissioning and operation
The unit is safely manufactured using state-of-the-art technology and complies with the respective
EU regulations. The unit could be dangerous if it is incorrectly installed or used.
Mechanical and electrical installation, commissioning and maintenance of the unit must only be
carried out by skilled and qualified personnel. The skilled personnel must have read and understood
these operating instructions and followed them carefully. Always make sure that the unit is correctly
connected following the electrical connection diagrams (see Chap. 4 "Electrical installation"). When
the unit covers are removed, all electrical contact protection is lost (danger of electrical shock). The
housing must only be opened by qualified skilled personnel.
1.3 Operational safety
Hazardous areas
The energy manager is classified as additional equipment and may not be installed in a hazardous
area.
Technical advancement
The manufacturer reserves the right to improve and update the technical details. For details of
improvements or additions to these instructions, please contact your local sales organisation.
1.4 Returns
Please contact both the transport agency and your supplier if any transport damage is discovered.

RMS 621 1 Safety notes
Endress+Hauser 9
1.5 Safety characters and symbols
Safety notes in these installation and operating instructions are highlighted using the following safety
pictograms:
"Caution!
This pictogram refers activities or sequences that, if done incorrectly could lead to personal injury
or faulty operation or complete damage to the unit.
#Warning!
This pictogram refers activities or sequences that, if done incorrectly could lead to personal injury,
a safety risk or total damage to the unit
!Note!
This pictogram refers activities or sequences that, if done incorrectly could have a direct influence
on the units operation or could release an unforeseen unit reaction.

2 Identification RMS 621
10 Endress+Hauser
2 Identification
2.1 Unit identification
2.1.1 Legend plate
Compare the unit legend plate with the following diagram:
Fig. 3: Energy manager legend plate (example)
1 Order code and unit series number
2 Protection class and allowable ambient temperature
3Powersupply
4 Temperature sensor input with measurement range
5 Approvals with accuracy details
6 Available in/outputs
2.2 Complete delivery
A complete delivery of an energy manager consists of:
•Energy manager RMS 621 for DIN top hat rail mounting
•This installation and operating manual
•CD-ROM data carrier with PC configuration software and RS 232 serial interface cable (optional)
•Remote display for panel mounting (optional)
•Expansion cards (optional)
!Note!
Take note of the accessories for the unit in Chap. 8 "Accessories".
2.3 Certificates and approvals
CE approval, certificate of conformity
The energy manager has been produced using the latest state-of-the-art technology, and leaves our
factory in a safe and tested condition. The unit complies with the EN 61010 regulations "Safety
requirements for electrical measurement, control and laboratory instrumentation".
This means that the unit described in this installation and operating manual fulfils the requirements
demanded by the EU regulations. The manufacturer acknowledges successful unit testing by adding
the CE mark.
The unit was developed in accordance with the OIML R75 and EN-1434 directives.
Made in Germany D-87484 Nesselwang 200x
Ordercode: xxxxxxxxxxxxxxx
Ser. No. : xxxxxxxxx
ENDRESS+HAUSER
RMS 621
18-36V DC , 20-28V AC 50/60 Hz
8-24 VA IP20
Temp. sensor Pt100/Pt500/Pt1000
Input: 4-20mA/PFM/Impulse
Output: 4-20mA/Impulse
Relays: contact ratings max. 250V/AC/5A
Assembly area:_____________
-20°C < Ta < 60°C
Temp. measurement range: 0...300°C water
0...800°C steam
OIML R75 Class 4 T 3...300 K (water)∆
Made in Germany D-87484 Nesselwang 200x
Ordercode: xxxxxxxxxxxxxxx
Ser. No. : xxxxxxxxx
ENDRESS+HAUSER
RMS 621
90-250 V AC 50/60 Hz
8-24 VA IP20
Temp. sensor Pt100/Pt500/Pt1000
Input: 4-20mA/PFM/Impulse
Output: 4-20mA/Impulse
Relays: contact ratings max. 250V/AC/5A
Assembly area:_____________
-20°C < Ta < 60°C
Temp. measurement range: 0...300°C water
0...800°C steam
OIML R75 Class 4 T 3...300 K (water)∆
1
3
4
5
6
2
1
3
4
5
6
2

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Endress+Hauser 11
3 Mechanical installation
3.1 Installation conditions
The permitted ambient temperature (see "Technical data") must not be exceeded in installation or
operation. The unit must be protected from any outside heat sources.
3.1.1 Installation dimensions
Take note of the 135 mm (equals 12 DU) unit installation depth. For further dimensions, please see
Chap. 10 "Technical data".
3.1.2 Installation area
Installation inside a control panel on top hat DIN rail according to EN 50 022-35. The installation
area must be free of vibration.
3.1.3 Installation orientation
No limitation.
3.2 Installation
First remove the keyed plug-on terminals from the housing. Snap the housing onto the DIN rail by
first hooking the unit onto the rail and snap in by using slight downwards pressure
(see Fig. 4, Pos. 1 and 2).
Fig. 4: Unit installation on DIN top hat rail

3 Mechanical installation RMS 621
12 Endress+Hauser
3.2.1 Installation of expansion cards
It is possible to fit various expansion cards into the unit. For this purpose there are a maximum of
three slots available. The expansion card plug in slots are identified as B, C and D (→Fig. 5) on the
unit.
1. When installing or removing expansion cards to or from the unit, always make sure that the
power supply is OFF.
2. Remove the blanking plate from the required expansion slot in the unit. This is done by
pressing the holding clips on the bottom of the energy manager together (see Fig. 5, Pos. 2),
simultaneously push the holding clip on the back of the unit inwards (e.g. using a screwdriver)
(see Fig. 5, Pos. 1), then push the blank housing upwards out of the unit.
3. The expansion card is slotted into the unit from the top. The expansion card is only correctly
fitted when the holding clips on the lower and rear sides of the unit have clicked into place
(see Fig. 5, Pos. 1 and 2). Make sure that the input terminals of the expansion card are at the
top and the analogue connection terminals to the base unit are facing the front.
4. The new expansion card is automatically recognised by the unit once it has been correctly
connected and set up (see Chap. "Commissioning").
Fig. 5: Installing a new expansion card (example)
Pos. 1: Holding clip on unit base
Pos. 2: Holding clips on lower side of the unit
Pos. A - E: Slot allocation identification
!Note!
If existing expansion cards are removed and not replaced, then the spaces must be filled by using
blanking cards.
3.3 Installation control
If using expansion cards, always make sure that they are correctly seated in the allocated slots of the
unit.
!Note!
When using the unit as a heat counter, take note of installation regulations EN 1434 Part 6. This
includes the installation of the flow and temperature sensors.

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4 Electrical installation
4.1 Electrical connection overview
Fig. 6: Energy manager slot connections (base unit)
Terminal layout
Terminal (Pos.no.) Terminal layout Slot In- and output
82 24 V sensor supply 1 A top front (A I) Current/PFM/pulse input 1
81 Sensor supply ground 1
10 + 0/4 to 20 mA/PFM/pulse input 1
11 Signal ground for 0/4 to 20 mA/PFM/pulse input
83 24 V sensor supply 2 A top back (A II) Current/PFM/pulse input 2
81 Sensor supply ground 2
110 + 0/4 to 20 mA/PFM/pulse input 2
11 Signal ground for 0/4 to 20 mA/PFM/pulse input
1 + RTD supply 1 E top front (E I) RTD input 1
5+RTDsensor1
6 - RTD sensor 1
2 - RTD supply1
3 + RTD supply 2 E top back (E II) RTD input 2
7+RTDsensor2
8 - RTD sensor 2
4 - RTD supply 2
101 - RxTx 1 E bottom front (E III) RS485
102 + RxTx 1
103 - RxTx 2 RS485 (as option)
104 + RxTx 2

4 Electrical installation RMS 621
14 Endress+Hauser
!Note!
The current/PFM/pulse inputs or RTD inputs in the same slot are not galvanically separated. There
is an isolation voltage of 500 V between the above inputs and outputs installed in different slots.
Terminals having the same identity are internally linked.
4.2 Connecting measurement sensors
"
Caution!
Do not install/connect the unit under power. If this is ignored it can lead to total damage of parts
of the electronics.
131 + 0/4 to 20 mA/pulse output 1 E bottom back (E IV) Current/pulse output 1
132 - 0/4 to 20 mA/pulse output 1
133 + 0/4 to 20 mA/pulse output 2 Current/pulse output 2
134 - 0/4 to 20 mA/pulse output 2
52 Relay common (COM) A bottom front (A III) Relay
53 Relay normally open (NO)
92 +24 V sensor supply Additional sensor supply
91 Supply ground
L/L+ L for AC
L+ for DC
A bottom back (A IV) Power supply
N/L- N for AC
L- for DC
RS232 Interface 3.5 mm jack plug socket
on front
Remote set up from PC
Terminal (Pos.no.) Terminal layout Slot In- and output
Top of unit connection view (inputs) Bottom of unit connection view (outputs, interfaces)

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4.2.1 Power supply connection
"Caution!
•Before installing the unit make sure that the supply to be used corresponds with that shown on
the unit legend plate.
•When operating with a 90 to 250 V AC (power supply) a power isolator must be situated within
easy reach of the unit. This should be fuse protected using a current rating of ≤10 A.
Fig. 7: Power supply connection
4.2.2 Connecting external sensors
!Note!
Both active and passive sensors with analogue, PFM, or pulse signals and RTD sensors can be
connected to the unit.
Dependent on the signal type, the terminals can be freely selected. This means that the energy
manager is very flexible in its application and the terminals are not bound to any particular sensor
type, e.g. flow sensor terminal 11, pressure sensor terminal 12 etc. If the unit is to be used as a heat
counter according to the OIML R 75, then the connection regulations contained in that norm are
valid.
Active sensors
Connection of an active sensor (this means external power supply).
Fig. 8: Connection of an active sensor, e.g. to input 1 (Slot AI)
Pos. 1: Pulse signal
Pos. 2: PFM signal
Pos. 3: 2-wire transmitter (4-20 mA)
Pos. 4: Connection of an active sensor, e.g. optional universal expansion card (Slot B I,
→ Fig. 13)

4 Electrical installation RMS 621
16 Endress+Hauser
Passive sensors
Connection of sensors that are powered using the loop power supply built into the unit.
Fig. 9: Connection of a passive sensor, e.g. to input 1 (Slot AI)
Pos. 1: Pulse signal
Pos. 2: PFM signal
Pos. 3: 2-wire transmitter (4-20 mA)
Pos. 4: Connection of a passive sensor, e.g. optional universal expansion card (Slot B I,
→ Fig. 13)
Temperature sensors
Connection for Pt100, Pt500 and Pt1000
!Note!
Terminals 1 and 5 (3 and 7) must be linked when using 3-wire sensors (see Fig. 10).
Fig. 10: Connection of temperature sensors, e.g. to input 1 (Slot EI)
Pos. 1: 4-wire input
Pos. 2: 3-wire input
Pos. 3: 3-wire input, e.g. optional temperature expansion card, (Slot B I,
→ Fig. 13)
E+H specific instrumentation
Flow sensors with PFM output
!Note!
Set the Prowirl flowmeter to PFM output
(ÆFU 20: ON, PF)

RMS 621 4 Electrical installation
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Flow sensors with open collector output
!Note!
Select the relative resistance R, so that I
max.
= does not
exceed 20 mA.
Flow sensors with a passive current output
(4 to 20 mA)
Flow sensors with an active current output
(4 to 20 mA)
Flow sensors with an active current output and an pas-
sive frequency output (measurement of bi-directional
flow)
!Note!
Select the relative resistance R, so that I
max.
= does not
exceed 20 mA.
Terminals 82/110 = Direction signal
Terminals 10/11 = Flow signal
Temperature sensor using an temperature head
transmitter (4 to 20 mA)
Pressure sensors with a passive current output
(4 to 20 mA)

4 Electrical installation RMS 621
18 Endress+Hauser
4.2.3 Output connections
The unit has two galvanically isolated outputs that can be set up as analogue outputs or
active/passive pulse outputs. In additionally there is one output available for connecting a relay and
loop power supply. The number of outputs increase if expansion cards are fitted.
Fig. 11: Output connections
Pos. 1: Pulse and current outputs (active)
Pos. 2: Passive pulse output (Open Collector)
Pos. 3: Relay output (normally open), e.g. Slot A III (Slot BIII, CIII, DIII on optional expansion card)
Pos. 4: Loop power supply output
Interface connection
•RS232 connection
The RS232 interface is connected using the interface cable delivered with the unit and the jack
plug socket on the front of the unit.
•RS485 connection
•Optional: additional RS485 interface
Terminals 103/104, this interface is only active so long as the RS232 interface is not being used.
Fig. 12: Interface connection

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4.2.4 Connecting expansion cards
Fig. 13: Expansion cards with terminals
Terminal layout of universal input expansion card (RMS621A-UA)
Terminal (Pos.no.) Terminal layout Slot In- and outputs
182 24 V power supply 1 B, C, D top front (B I, C I,
D I)
Current/PFM/pulse input 1
181 Ground power supply 1
112 + 0/4 to 20 mA/PFM/pulse input 1
111 Signal ground for 0/4 to 20 mA/PFM/pulse input
183 24 V power supply 2 B, C, D top back (B II, C
II, D II)
Current/PFM/pulse input 2
181 Ground power supply 2
113 + 0/4 to 20 mA/PFM/pulse input 1
111 Signal ground for 0/4 to 20 mA/PFM/pulse input
142 Relay 1 Common (COM) B, C, D bottom front (B
III, C III, D III)
Relay1
143 Relay 1 normally open (NO)
152 Relay 2 Common (COM) Relay 2
153 Relay 2 normally open (NO)
131 + 0/4 to 20 mA/pulse output 1 B, C, D bottom middle (B
IV, C IV, D IV)
Current/pulse output 1 active
132 - 0/4 to 20 mA/pulse output 1
133 + 0/4 to 20 mA/pulse output 2 Current/pulse output 2 active
134 - 0/4 to 20 mA/pulse output 2
135 + Pulse output 3 (Open collector) B, C, D bottom back (B V,
C V, D V)
Passive pulse output
136 - Pulse output 3
137 + Pulse output 4 (Open collector) Passive pulse output
138 - Pulse output 4

4 Electrical installation RMS 621
20 Endress+Hauser
Terminal layout of the temperature expansion card (RMS621A-TA)
!Note!
The current/PFM/pulse input inputs or RTD inputs of individual cards are not galvanically isolated.
There is an isolation voltage of 500 V between the above mentioned inputs and outputs in differing
slots as well as the outputs of individual cards. Similar terminals are internally linked.
4.2.5 Connecting the remote display/operating module
Function description
The remote display is an innovative expansion to the powerful DIN rail mounted RMS621 unit. For
the user this means that the calculation unit can be installed technically correct and the display and
operating module can be mounted in an easily accessible and user friendly position. The display can
be connected to a DIN rail mounted unit that has already got an integrated display/operating
module as well as one without a display/operating module. In order to connect the remote display
a four core cable is supplied, other components are not required.
!Note!
Only one remote display/operating unit can be connected to a DIN rail mounted unit and Vica Versa
(point to point).
Terminal (Pos.no.) Terminal layout Slot In- and outputs
117 + RTD supply 1 B, C, D top front (B I, C I,
D I)
RTD input 1
116 + RTD sensor 1
115 - RTD sensor 1
114 - RTD supply 1
121 + RTD supply 2 B, C, D top back (B II, C
II, D II)
RTD input 2
120 + RTD sensor 2
119 - RTD sensor 2
118 - RTD supply 2
142 Relay 1 Common (COM) B, C, D bottom front (B
III, C III, D III)
Relay1
143 Relay 1 normally open (NO)
152 Relay 2 Common (COM) Relay 2
153 Relay 2 normally open (NO)
131 + 0/4 to 20 mA/pulse output 1 B, C, D bottom middle (B
IV, C IV, D IV)
Current/pulse output 1 active
132 - 0/4 to 20 mA/pulse output 1
133 + 0/4 to 20 mA/pulse output 2 Current/pulse output 2 active
134 - 0/4 to 20 mA/pulse output 2
135 + Pulse output 3 (Open collector) B, C, D bottom back (B V,
C V, D V)
Passive pulse output
136 - Pulse output 3
137 + Pulse output 4 (Open collector) Passive pulse output
138 - Pulse output 4