Endress+Hauser RH33 Specifications
TI00151K/09/EN/02.13
71241091
Products Solutions Services
Technical Information
EngyCal® RH33
BTU meter
Custody transfer BTU meter for recording and
billing the heat/cold quantity given off by water,
water/glycol mixtures or other liquids
Transparent energy consumption helps you save on
energy costs
Application
Recording and billing the quantities of heat and cold in:
•Heating circuits
• Cooling circuits
• Combined heating and cooling circuits
Typical application areas in industry, long-distance heat networks and building automation.
Your benefits
• Verified and certified reliability and accuracy
• Standard models are suitable for connecting and supplying all common volume flow
transmitters and temperature measuring points
• Detailed data logging of current and counter values and of error messages, off-limit
conditions and changes to operating parameters
• Industry-compliant compact housing for field or wall mounting, panel mounting or
top-hat rail mounting
• Deficit counter for transparency in case of error or alarm
• Custody transfer logbook enables versatile device configuration in the field
• Tariff counter for requirements-based billing
• Calibrated, electronically paired temperature sensors ensure the highest accuracy
and enable replacement of individual temperature sensors even for certified devices
in the field (without reapproval!)
• Remote readout via Ethernet and fieldbuses
EngyCal® RH33
q
T
warm
T
cold
Function and system design
Measuring principle The EngyCal® RH33 BTU meter is used to measure the heat and cold in systems with liquid heat trans-
fer fluids. It is easy to install and read. Thanks to its verified long-term stability and high-precision
measurements, the device helps optimize processes and control costs in the process. Comprehensive
data analysis options in the Field Data Manager software MS20 (see accessories) identify potential
areas for cost reduction.
Measuring system
Measuring system with EngyCal ® RH33, 2x paired temperature sensors and flow sensor
Functions Energy calculation
EngyCal
®
RH33 calculates the thermal energy of water, glycol/water mixtures or other liquids such as
thermal oils in accordance with EN1434.
Calculation basis: IAWPS-IF97
Calculated values:
• Power
•Volume
•Density
• Enthalpy & enthalpy differential
• DP flow compensation
•Mass
• Temperature differential
Counters
Volume, mass, energy, deficit
Optional: tariff1, tariff2 or separate heat/cold energy, balance energy
Fault mode / deficit counter
The fault mode of the EngyCal
error value). Thanks to the defined fault mode and the separate deficit counter, the device guarantees
transparency for energy calculation and documentation for billing.
For the case of further calculation with an error value, the total calculated energy during the error condition is counted on a deficit counter.
In this case, the output continues to supply the calculated energy value. If values are communicated via
buses, these are given the value "invalid". Optionally, an alarm relay can be switched.
a0013618-en
®
RH33 can be defined freely (no further calculation or calculation with
User-defined heat transfer media
Heat transfer media in cooling circuits usually consist of glycol-water mixtures. Mixtures for the following glycols are already predefined in the EngyCal®:
• Ethylene-glycol
•Antifrogen N
• Glykosol N
•Propylene glycol
For these glycol-water mixtures it is possible to enter the glycol concentration for accurate calculations.
If other heat transfer media are used (e.g. thermal oils, cooling agents), the liquid data must be programmed into the device. Tables are available for this purpose in which the user can enter the density
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EngyCal® RH33
and thermal capacity (max. 10 support points). For devices with the "DP Flow Measurement" option,
another table with two support points is available for entering the viscosity data.
The values between or outside the support points are determined by interpolation or extrapolation.
Temperature sensor matching in the device
®
The temperature sensors are paired internally in the EngyCal
RH33 by storing the sensor characteristic curves via Callendar-van-Dusen coefficients. The Callendar-van-Dusen coefficients are determined by calibrating the temperature sensor.
The internal alignment function makes it possible to use unpaired sensors, and to replace one sensor
independently of the second sensor while maintaining or improving accuracy levels (compared to using
paired sensors).
Compensation of differential pressure flow measurement
The flow calculation according to the differential pressure method is a special form of flow measurement. Volume or mass flow values measured according to the DP method require a specific correction.
The iterative solution of the calculation equations listed there allow the best possible accuracy (ca. 0.6
– 1 %) to be attained for DP flow measurements.
Compensation of flow measurement for throttle methods (orifice plate, nozzle).
The measurement (orifice plate, nozzle, Venturi pipe) is carried out according to ISO5167. Flow measurements according to the dynamic pressure method are determined according to the relationship
between the differential pressure and flow.
Data logging and logbook
Event logbook:
The EngyCal RH33
®
BTU meter has a logbook for measured values and a logbook for events.
In the event logbook, all parameter changes, off-limit conditions, alarms and other events are documented with timestamp such that they are tamper-proof. At minimum, the last 1600 events are stored
in non-volatile memory.
The data logging allows process values and calculated values, as well as counters, to be stored in freely
definable intervals. Predefined analyses (Day, Month, Year, Billing dates) support the transparency of
the process and ensure a quick overview of all consumption values.
All entries into the event logbook and the logged data can be read out automatically via the visualization software (Field Data Manager Software) and backed up in an SQL database so that it is tamperproof.
For fast and easy-to-understand analysis in case of service, an internal diagnostic memory with
occurred error messages is also available.
Analysis No. of analyses
Interval (1min) Approx. 700
Day 260 days
Month/year/billing date 17 years
Events At least 1600 (depending on the length of the message text)
Approval for custody transfer and custody transfer logbook
The device is equipped with a custody transfer switch, which disables configuration ranges that are relevant for custody transfer.
The custody transfer switch is located inside the device. The housing is lead-sealed.
The switch is enabled before delivery if the device is ordered with approval for custody transfer. Following this, it is possible to reconfigure relevant device settings three times. All changes to the parameters are logged in the custody transfer logbook and time-stamped.
The switch can only be reset by the manufacturer.
Thus the seamless documentation enables versatile commissioning and parameter configuration of
the computer in the field (without loss of custody transfer approval).
Limit value monitoring
Three limits can be assigned as desired the following measured and calculated values:
Volume flow, temperature, pressure, mass flow, power (heat flow), density, enthalpy, operating volume, heat and tariff 1, tariff 2
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EngyCal® RH33
In case of violation of the defined limits, an entry is made into the event logbook. In addition, relays
can be switched and the off-limit condition can be indicated in the display. Limits are also visible via
the integrated Web server.
Bidirectional measurement (optional)
®
EngyCal
RH33 enables bidirectional measurement, i.e. the combined measurement of heat and cold,
for example when charging/discharging a heat accumulator, including calculation of the quantities of
heat. The bidirectional measurement can be flow-dependent or temperature-dependent.
This option cannot be combined with the tariff function.
A digital input can be used to detect the flow direction.
Tariff counters (optional)
The tariff counters enable analysis and recording of the energy on an additional counter.
Two types of tariff counter are available: A defined tariff can be activated by an event or via the digital
inputs. If the defined event occurs, the calculated energy is counted at this tariff.
Tariff counters enable, for example, invoicing on specific billing dates (due date invoicing), requirements-based billing (daytime/nighttime tariff) and analysis of counters when reaching set points, e.g.
power-dependent.
Various tariff models are available for selection in the device, e.g. Energy; Power, warm; Power, cold;
Time.
The standard counters continue running at the same time, e.g. they are not affected by the activation
of the tariff counters.
This option cannot be combined with the bidirectional measurement function.
Real time clock (RTC)
The device has a real time clock that can be synchronized via a free digital input or using the Field Data
Manager software MS20.
The real time clock continues running even in case of a power failure, the device documents power on
and off; the clock switches automatically or (optionally) manually from daylight saving to standard
time.
Display
To display measured values, counters and calculated values, 6 groups are available. Each group can be
assigned up to 3 values or meter readings as desired.
Analyzing the stored data - Field Data Manager software MS20
The Field Data Manager Software allows the stored measured values, alarms and events, and the
device configuration to be read out from the device (automatically) so that they are tamper-proof and
stored securely in an SQL database. The software offers centralized data management with a variety of
visualization functions. Using an integrated system service, analyses and reports can be created,
printed and stored fully automatically. Security is provided by the FDA-compliant audit trail of the software and the extensive user management. Simultaneous access and analysis of data from various
workstations or users is supported (client-server architecture).
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EngyCal® RH33
Input
Current/pulse input Th is inp ut can b e u sed eithe r a s a c urren t inpu t f or 0 /4 to 2 0 mA sig nals (n ot if th e appr oval fo r c ust ody
transfer option has been selected) or as a pulse/frequency input.
The input is galvanically isolated (500 V testing voltage towards all other inputs and outputs).
Cycle time
The cycle time is 250 ms or 500 ms respectively when using one or two RTD inputs.
Reaction time
In the case of analog signals, the reaction time is the time between the change at the input and the
time when the output signal is equivalent to 90% of the full scale value. The reaction time is lengthened
by 250 ms if an RTD with 3-wire measurement is connected.
Input Output Reaction time [ms]
Current Current ≤ 600
Current Relay/digital output ≤ 600
RTD Current/ relay/digital output ≤ 600
Cable open circuit detection Current/ relay/digital output ≤ 600
Cable open circuit detection, RTD Current/ relay/digital output ≤ 1100
Pulse input Pulse output ≤ 600
Current input
Measuring range: 0/4 to 20 mA + 10 % over range
Accuracy: 0.1 % of full scale value
Temperature drift: 0.01 %/K (0.0056 %/°F) of the full scale value
Loading capacity: Max. 50 mA, max. 2.5 V
Input impedance (load): 50 Ω
®
signals Not affected
HART
A/D converter resolution: 20 bit
Pulse/frequency input
The pulse/frequency input can be configured for different frequency ranges:
• Pulses and frequencies up to 12.5 kHz
• Pulses and frequencies up to 25 Hz (filters out bounce contacts, max. bounce time: 5 ms)
Minimum pulse width:
Range up to 12.5 kHz
Range up to 25 Hz
Maximum permissible contact bounce time:
Range up to 25 Hz 5 ms
Pulse input for active voltage pulses and contact sensors as per EN 1434-2, Class IB and IC:
Non-conductive state
Conductive state
No-load supply voltage: 3 V to 6 V
Current limiting resistance in the power supply
(pull-up at input): 50 kΩ to 2 MΩ
Maximum permissible input voltage: 30 V (for active voltage pulses)
40 μs
20 ms
≤ 1 V
≥ 2 V
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EngyCal® RH33
Pulse input for contact sensors as per EN 1434-2, Class ID and IE:
Low-level
High-level
No-load supply voltage: 7 V to 9 V
Current limiting resistance in the power supply
(pull-up at input):
Not suitable for active input voltages.
Current/pulse input:
Low-level
High-level
Loading capacity: Max. 50 mA, max. 2.5 V
Input impedance (load): 50 Ω
Accuracy during frequency measurement:
Basic accuracy: 0.01 % of measured value
Temperature drift: 0.01 % of measured value over entire temperature range
≤ 1.2 mA
≥ 2.1 mA
562 Ωto 1 kΩ
≤ 8 mA
≥ 13 mA
Pulse output of the flow
RH33 setting Electrical connection Remark
sensor
Mechanical contact Pulse ID/IE up to25 Hz
Open Collector (NPN) Pulse ID/IE up to 25 Hz
or up to 12.5 kHz
Active voltage Pulse IB/IC+U
A Sensor
B RH33
A Sensor
B RH33
"Pulse IB/IC+U" up to 25 Hz can
also be used. The current through
the contact is lower then (approx.
0.05 mA instead of 9 mA).
Advantage: less load;
disadvantage: lower interference
resistance.
A0015354
"Pulse IB/IC+U" can also be used.
The current through the contact is
lower then (approx. 0.05 mA
instead of 9 mA). Advantage: less
load; disadvantage: lower
interference resistance.
A0015355
The switching threshold is
between 1 V and 2 V
A0015356
A Sensor
B RH33
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