SLQ-QT500 Datasheet, PDF (3/7 Pages) List of Unclassifed Manufacturers – High Purity Flow Meter

3 Communication with the Liquid Flow Meter
The SLQ-QT500 flow meter shows bidirectional,
linear transfer characteristics. The product comes
fully calibrated for IPA and water.
Digital sampling time at 16 bit resolution: 74 ms
Digital sampling time at 9 bit resolution: 1 ms
3.1 Electrical Specifications
This section describes electrical specifications when
connecting directly to the sensor’s M8 connector for
I²C communication. The preferred mode of
communication is via the SCC1 interface cables. See
the respective SCC1 datasheets for further details.
Table 2: DC characteristics
Parameter Conditions
Power supply
DC, VDD
Operating
current
Min. Typ. Max. Unit
3.3 3.5 3.7 V
5.1
mA
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)
3.3 Digital Communication via RS485-Bus
The SCC1-RS485 Sensor Cable for liquid flow meters
provides 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 flow meter, 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 readout.
For further information please see the SCC1-RS485
Sensor Cable datasheet, available on
www.sensirion.com/liquidflow-download.
3.4 Analog Communication
The SCC1-ANALOG Sensor Cable allows simple and
quick readout of Sensirion’s liquid flow meters by
converting the digital flow meter reading to a 0...10 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-
ANALOG Sensor Cable datasheet, available on
www.sensirion.com/liquidflow-download.
3.5 Communication via USB cable
The Sensirion SCC1-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.
3.6 Digital Communication via I²C-Bus
The SLQ-QT500 liquid flow meter has been designed
for use with the SCC1 interface cables. For special
applications, direct communication with the flow meter
via the standard I²C-interface is possible. 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 have to be used on 3.3 V level with a
recommended clock frequency of 100 kHz. For the
detailed specifications of this I²C communication,
please refer to specific I²C Application Notes from
Sensirion.
www.sensirion.com
Version 3 – October 2014
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