Hobo S-FS-TRMSA, S-FS-TRMSA-D User Manual

FlexSmart™ TRMS Module (S-FS-TRMSA & S-FS-TRMSA-D) Manual

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The S-FS-TRMSA and S-FS-TRMSA-D are easy-to-configure, True-RMS input measurement
modules. The S-FS-TRMSA is compatible with HOBO® H22 series data loggers. The S-FS-TRMSA-D
is compatible with HOBO H22 loggers, U30 stations, and RX3000 stations. The “-D” variant has a
modular connector for connecting to an available smart-sensor port. Both 2-channel modules
have an input range of 512 millivolts RMS full-scale. Thus, they are fully compatible with
industry-standard voltage and current transformers (PT and CT) which output 333 millivolts RMS
full-scale.

The modules feature extremely low-power operation, resulting in long battery life for
unattended data logging applications.

Note: Refer to the H22 logger, U30 or RX3000 station, and HOBOware® software manuals at
www.onsetcomp.com/support/manuals for additional information on using and configuring the
FlexSmart TRMS module.

FlexSmart TRMS Module

Models: S-FS-TRMSA

S-FS-TRMSA-D

Included Items:

• Detachable screw terminal
connector

• Imprintable label

Specifications

Input Channels Two; AC-coupled

Field Wiring Two-wire via screw terminals on detachable connector, 16-24 AWG

Input Range 5 to 512 mVRMS

Minimum Input Voltage 5mVRMS; Input voltages < 5mV will be clipped to zero (see graph

Maximum Input Voltage

Input Frequency 50/60 Hz

ccuracy ±0.3% of reading +/- 0.5% of FSR

ADC Resolution 15 bits

AC Waveform <4 Crest Factor

Power Requirements

Transfer Function

Measurement Averaging Option Yes

Replacement detachable connectors: Part of spares kit (A-FS-TRMSA­4P-1)

below)

±1V referred to AC- terminals (pins 2 and 4)

+3.3V @ 3mA active, 6μA sleep

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The CE Marking identifies this product as complying with all relevant
directives in the European Union (EU).

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10093-H MAN-S-FS-TRMSA

Minimum Input Voltage Graph

FlexSmart TRMS Module (S-FS-TRMSA & S-FS-TRMSA-D) Manual

Module Connections

Potential Transformers (PT) and Current Transducers (CT) are
connected to the module via a four-pin Phoenix-style
detachable screw terminal connector. Once the PTs and/or CTs
are connected, the module can then be configured using
HOBOware software with the module installed on the HOBO
H22 or U30 series logger or using HOBOlink® with the RX3000
station. Note: There are limitations to the number of modules
and smart sensors you can use with an RX3000 station. If you
are using both TRMSA-D modules and smart sensors, then you
are limited to a maximum of three TRMSA-D and any
combination of smart sensors to reach a total of 13 data
channels. For example, if there are three TRMSA-D modules in
use with the RX3000 station (each module has two channels for
a total of six in all), then this will leave seven additional data
channels for smart sensors. Similarly, if there are two TRMSA-D
modules in use with RX3000 station, then this will leave nine
additional data channels for smart sensors. Refer to the smart
sensor manuals at www.onsetcomp.com/support/manuals for
the number of data channels used by a specific smart sensor. If
you are not using smart sensors with the RX3000 station, then
you are limited to a maximum of four TRMSA-D modules.
Exceeding these guidelines may result in erroneous readings.

The diagram below illustrates typical connections for a PT and
CT. For module connection instructions specific to PTs and CTs
purchased from Onset, refer to the documentation provided
with each PT and CT.

Note: For three-phase monitoring, each of the three modules
should be wired so that similar parameters are connected to
corresponding pin numbers. For example, voltage inputs pins 1
and 2 on each module; current inputs pins 3 and 4 on each
module.

Measurement Averaging

This module supports measurement averaging. When
measurement averaging is enabled, data is sampled more
frequently than it is logged. The multiple samples are then
averaged together and the average value is stored as the data
for the interval. For example, if the logging interval is set at 10
minutes and the sampling interval is set at 1 minute, each
recorded data point will be the average of 10 measurements.
Measurement averaging is useful for reducing noise in the data.

1-800-LOGGERS (564-4377) • 508-759-9500
www.onsetcomp.com/support/contact

© 2008–2018 Onset Computer Corporation. All rights reserved. Onset, HOBO, FlexSmart, HOBOware, and
HOBOlink are trademarks or registered trademarks of Onset Computer Corporation. All other trademarks are
the property of their respective companies.

10093-H MAN-S-FS-TRMSA