SLI Liquid Flow Meter Series
Media Isolated Microfluidic Flow Meter
Liquid flow rates up to 10 ml/min
Non-invasive measurement
Different interface options
40 ms flow detection response time
Product Summary
The SLI Liquid Flow Meter enables fast, non-invasive
measurements of very low liquid flow in the µl/min- to
ml/min-range. Excellent chemical resistance is ensured:
The flow path of the SLI Liquid Flow Meter is formed by a
simple, straight glass capillary. The fourth generation
MEMS sensors combine a thermal high precision sensor
element with amplification circuits and digital intelligence
for linearization and temperature compensation on one
single microchip – the product’s core element.
Interface Options
Digital
- I
2
C-Bus
- RS485-Bus
- USB Cable
Analog
- Voltage Output (0-10 V)
- Additional operation
modes
For more information on communication, please refer
to page 2 of this document.
1
Sensing Performance
Parameter
H
2
O Full scale flow rate
H
2
O Sensor output limit
a
Accuracy below full scale
(whichever error is larger)
Repeatability below full scale
(whichever error is larger)
Temperature coefficient
(additional error / °C; whichever is larger)
Mounting orientation sensitivity
d
Flow detection response time
63
Response time on power-up
Operating temperature
Ambient storage temperature
e
Maximum recommended operating pressure
Burst pressure
SLI-0430
80
120
5.0
0.15
0.5
0.01
0.13
0.003
<0.4
SLI-1000
1000
1100
5.0
0.2
0.5
0.02
0.1
0.004
1.0
40
120
+10…+50
-10…+60
15
30
SLI-2000
5000
5500
b
5.0
0.2
0.5
0.02
0.1
0.004
1.5
Unit
µl/min
µl/min
% of m.v.
c
% of full scale
% of m.v.
% of full scale
% m.v. / °C
% full scale / °C
% of full scale
ms
ms
°C
°C
bar
bar
Table 1: Model specific performance of SLI (all data for medium
H
2
O,
23°C)
50
150
15
30
rate at which the sensor output saturates. See section 2 for performance between full scale and saturation point
range up to 10500 µl/min, see section 2 for performance specifications
c
Measured value
d
Maximum additional offset when mounted vertically
e
Non-condensing, flow path empty
b
Extended
a
Flow
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Table 2: Model specific performance of SLI (all data for medium
IPA,
23°C)
Parameter
IPA full scale flow rate
Sensor output limit
a
Accuracy below full scale
(whichever error is larger)
Repeatability below full scale
(whichever error is larger)
Temperature coefficient
(additional error / °C; whichever is larger)
a
Flow rate at which the sensor output
b
Measured
SLI-0430
500
600
20
1
1
0.05
0.5
.5
0.025
SLI-1000
10’000
SLI-2000
80
Unit
µl/min
ml/min
µl/min
ml/min
% of m.v.
b
% of full scale
% of m.v.
% of full scale
% m.v. / °C
% full scale / °C
11’000
20
1
1
0.05
0.4
0.02
90
10
0.5
1.5
0.03
0.35
0.02
saturates
value
1.1 Calibration Field Information
The SLI Liquid Flow Meters hold calibrations for two liquids, one for water (H
2
O) and one for isopropyl alcohol (IPA).
Each calibration is stored on a separate calibration field (CF):
Calibration field 0: H
2
O (factory default)
Calibration field 1: IPA
Calibration field 2 (SLI-2000 only, starting from SN 1627-00000): H
2
O extended range
The default calibration field (i.e. the active calibration field at power up) can be permanently changed via I
2
C or
RS485 commands. Alternatively, the default calibration field can be changed using the USB-RS485 Sensor Viewer
which is part of the Liquid Flow Meter Kit and also available in the download center on the Sensirion liquid flow
webpage.
www.sensirion.com/liquidflow-download
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3
Communication with the Sensor
3.4 Digital Communication via RS485-Bus
The SCC1-RS485 Sensor Cable for flow sensors
allows the communication via RS485 interface for use
in a demanding industrial automation environment. In
addition to the standard commands available in the
I²C interface of the sensor, the incorporated
microcontroller of the cable provides more complex
logic such as a dispense volume totalizer, automatic
dispense detection, automatic heater control and data
buffer for asynchronous read-out.
For further information please see the SCC1-RS485
Sensor Cable datasheet, available on
www.sensirion.com/liquidflow-download.
The
SLI flow meter
shows bidirectional, linear transfer
characteristics. The product comes fully calibrated for
water and IPA.
Digital Sampling Time, 16 bit
Digital Sampling Time, 9 bit
74 ms
1 ms
3.1 Electrical Specifications
Table 3: DC Characteristics
Parameter
Conditions
Power Supply
DC, VDD
Sensor only
RS485 cable
Analog cable
VDD = 4-6 V,
no load
RS485 cable
Analog cable
Min. Typ. Max. Units
4
4
12
5
5
5
24
5.5
20
4.3
6
6
36
6
70
V
V
V
mA
mA
mA
Operating
Current
3.5 Analog Communication
The SCC1-ANALOG Sensor Cable allows simple and
quick readout of Sensirion’s liquid flow meters by
converting the digital sensor reading to a 0...10.5 V
analog voltage output. Additionally, a digital (high/low)
output with two different modes of operation is
available (Flow Switch / Volume Counter)
For further information please see the SCC1-USB
Sensor Cable datasheet, available on
www.sensirion.com/liquidflow-download.
3.2 Electrical Connector and Pinout
The flow meter is equipped with a male connector
type M8, 4-pin, threaded lock according to
IEC 61076-2-101 (Ed. 1)/ IEC 60947-5-2, and is
compatible with Sensirion’s SCC1 interface cables.
Table 3: Electrical pinout
Pin
1
SDA (data)
2
GND
3
VDD
4
SCL (clock)
3.6 Digital Communication via I²C-Bus
Digital
communication between a master and the
SLI
sensor runs via the standard I²C-interface. The
physical interface consists of two bus lines, a data line
(SDA) and a clock line (SCL) which need to be
connected via pull-up resistors to the bus voltage of
the system.
These lines can be used on 3.3V or 5.0V level with a
clock frequency of 100 kHz. For the detailed
specifications of this I²C communication, please refer
to specific I²C Application Notes
from Sensirion.
3.3 Communication via USB cable
The Sensirion USB Sensor Cable provides an easy to
use USB Interface for laboratory and desktop use.
For further information please see the SCC1-USB
Sensor Cable datasheet, available on
www.sensirion.com/liquidflow-download.
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