I²C Pressure Sensor | Pa6DC

At a Glance

Description

Applied Measurements I²C pressure sensor Pa6DC uses an I²C (Inter-Integrated Circuit) protocol to communicate with the controller.  The I²C output is ideal for OEM, machine feedback systems, control systems and automation applications.

I²C Pressure Transducer Prices Start From:

• 1+ = £120.00
• 10+ = £115.00
• 25+ = £108.00
• 50+ = £102.00
• 100+ = £97.00

The benefit of using our I²C pressure transducer with an I²C interface is that it can be supported along with many I²C devices on the same circuit. I²C protocol allows a maximum of 127 target devices on the bus. This I²C pressure sensor is designed to work as a target on an I²C protocol bus.

As with most I²C devices, the I²C pressure sensor uses only 2 wires to transmit data between the devices on the system (2 further wires are required from the pressure sensor for the +ve and -ve supply, see I²C protocol diagram below).

The pressure sensor’s housing is constructed from 303 stainless steel (alternative materials including 316 stainless steel and PVDF are available) and utilises a ceramic sensing diaphragm (96% aluminium oxide Al2O3), a Viton O-ring and a G¼ inch male process connection as standard, giving the sensor an IP65 splashproof protection rating.

Thanks to its IP65 sealing, it can be used for the measurement of gas and liquid pressure in many I²C industrial applications.

We can easily accommodate any requirement from one-off to bulk orders for many thousands of sensors, all within our in-house, UK production facility.

Alternate casing and construction materials, O-rings and process connections can all be offered, including G¼” female and ¼” NPT male connectors.  Should you require a pressure sensor tailored to your specific pressure measurement application, we can design and manufacture fully customised sensors for you – please contact our friendly sales team to discuss your requirements in detail.

How I²C Protocol Works

I²C communication protocol uses 2 wires to transmit information between the controller and the target on an I²C bus, the SDA and the SCL. The Serial Data Line (SDA) carries the data bi-directionally between the controller and the target device. The Serial Clock Line carries the clock signal ensuring the target and the controller’s clock are synchronised. The Clock signal is always controlled by the controller.

Each I²C device connected to the bus has a unique address. This is used by the controller to differentiate between the various target devices on the I²C bus. The I²C pressure sensor works as a target on the bus.

Benefits of an I²C Communication Bus

• Easy to add on, remove and modify the design by easily clipping on and clipping off the I²C devices.
• Easy to install as the I²C communications protocol is already embedded on the chip inside the sensor.
• Simple 2-wire data transfer.
• Easy fault finding with the unique address of every I²C-connected device.
• Low current consumption.

Technical Specifications

Input Pressure Range
Nominal Pressure Range	Bar (gauge, absolute or sealed gauge	0-0.5	0-1	0-2	0-5	0-10	0-20	0-50	0-100	0-200	0-400	0-600	0-700
Compound Ranges	Bar	-0.5…0 *	-1…0 *	-1…+2 *	-1…+5	-1…+9	-1...+19	-1...+29	-	-	-	-	-
Permissible Overpressure	Bar	1	2	4	10	15	35	100	150	350	500	800	900
Burst Pressure	Bar	2	3	6	15	25	65	120	200	500	650	950	950
*<±0.1% / FS (BFSL) accuracy not possible in this range

Output Signal & Supply Voltage	Wiring System	Output	Supply Voltage	Input Current (idle)
Pa6DC	4-wire	I²C	2.7-5.5Vdc	<3mA

Performance
Accuracy (Non-Linearity, Hysteresis & Repeatability)	±%/Rated Output (BFSL)	<±0.25 <±0.1 optional
Zero Balance	±% of Rated Output	<1.0
Setting Errors (offsets)		Zero & Full Scale, <±0.5% / FS
Influence Effects	Supply Effects	<0.005 % FS / 1V
Response Time (10% - 90%)	ms	1 minimum, dependent on device configuration
Start-Up Time	ms	2
Wake-Up Time (from Sleep Mode)	µs	10
Internal I²C Pull-Up Resistors	kΩ	4.7
Permissible Temperatures & Thermal Effects
Media Temperature (Note: subject to 'O' ring seal, see below)	˚C	-40 to +135
Ambient Temperature	˚C	-20 to +85
Storage Temperature	˚C	-20 to +85
Compensated Temperature Range	˚C	+20 to +80
Thermal Zero Shift (TZS)	% / FS / ˚C	<±0.04 (standard) <±0.02 (option) <±0.01 (option)
Thermal Span Shift (TSS)	% output / ˚C	<±0.015 typical
Electrical Protection
Reverse Polarity Protection		No damage but also no function
Electromagnetic Compatibility		CE Compliant
Insulation Resistance	Megohms Ω at 50V dc	>500
Mechanical Stability
Shock		100 g / 11 ms
Vibration		10 g RMS (20 ... 2000 Hz)
Materials
Housing & Process Connection		303 Stainless Steel 316L Stainless Steel (optional)
‘O’ Ring Seals (inc. Temperature Range)		Viton (-20ºC to +135ºC) NBR/Nitrile (-40ºC to +100ºC) (optional) EPDM (-40ºC to +130ºC) (optional) Chemraz (-10ºC to +135ºC) (optional)
Diaphragm		Ceramic Al2O3 96 %
Media Wetted Parts		Housing and process connection, ‘O’ ring seal, diaphragm
Misc
Weight	grams	100 nominal
Installation Position		Any
Operational Life	pressure cycles	>100 x 10^6
Environmental Protection	Cable Gland M12x1 Connector	IP65 IP67 (note: mating half must be IP67-rated as well)

Product Dimensions

I²C Pressure Sensor Pa6DC M12 Outline

I²C Pressure Transducer Pa6DC Gland Outline

Wiring Details

Electrical Connection Type	+ve Supply	-ve Supply	SCL	SDA
M12x1 Connector	Pin 1	Pin 2	Pin 3	Pin 4
Cable Gland	Red	Blue	Green	Yellow

Ordering Codes & Options

Pa6DCM-10barg-A4AV-00-000	Pa6D	C	M	-	10barg	-	A	4	A	V	-	00	-	000
Product Family
Pa6D	Pa6D
Electrical Output
C = I2C		C
Electrical Connection / ATEX Certification
C = IP65 Cable Gland + Screened, Un-Vented PVC Cable			C
M = M12x1 4-pin Connector			M
MM = M12x1 4-pin Connector + Mating Half			MM
Pressure Range
10barg = 0 to 10bar gauge					10barg
M1P1barg = -1 to +1bar gauge					M1P1barg
5bara = 0 to 5bar absolute					5bara
2400psig = 0 to 2400psi gauge					2400psig
Accuracy (Non-Linearity & Hysteresis)
A = <±0.25%/FS (standard)							A
B = <±0.1%/FS							B
Zero Temperature Compensation (TZS)
4 = <±0.04%/FS/ºC								4
2 = <±0.02%/FS/ºC								2
1 = <±0.01%/FS/ºC								1
Continued on next page
Process Connection
A = G¼” Male DIN 3852 in 303 St/Steel									A
B = G¼” Male DIN 3852 in 316L St/Steel									B
C = ¼” NPT Male 303 St/Steel									C
D = 7/16 UNF-20 Male									D
E = G¼” Female in 303 St/Steel									E
F = G¼” Male DIN 3852 in PVDF (Polyvinylidene Fluoride)									F
S = 9/16 UNF Internal (no bleed hole)									S
O-Ring Material
V = Viton (FKM)										V
N = Nitrile (NBR)										N
E = EPDM (Ethylene Propylene Diene Monomer)										E
C = Chemraz (Perfluoroelastomer)										C
Cable Length (in metres)
00 = None												00
01 = 1 metre												01
04 = 4 metres (maximum allowed)												04
Specials Code
000 = No Special Requirements														000

I²C Communication Information

For I²C Protocol details and commands, please refer to the datasheet of the signal conditioning IC contained within the sensor. Additional NVM registers are used to store calibration data as per the table below:

I2C Slave Default address: 00	Clock Frequency: 400 kHz
Data is 24 bit unsigned absolute value	NOTE: Address Values in Hex
Calibration Data Memory Locations
16 bit Device Serial Number: ● NVM Address 00: bits 0 to 15 (LSB) ● NVM Address 01: bits 16 to 23 (MSB)
16 bit Device Zero Pressure Range: ● NVM Address 2A: bits 0 to 15	24 bit Corrected ZERO calibration reading: ● NVM Address 24: bits 0 to 15 (LSB) ● NVM Address 25: bits 16 to 23 (MSB)
16 bit Device Full Scale Pressure Range: ● Address 2C: bits 0 to 15	24 bit Corrected FULL SCALE calibration reading: ● NVM Address 26: bits 0 to 15 (LSB) ● NVM Address 27: bits 16 to 23 (MSB)
16 bit Device Zero Decimal Place: ● NVM Address 2B: bits 0 to 15	16 bit Device Full Scale Decimal Place: ● NVM Address 2D: bits 0 to 15
16 bit Device Pressure Engineering Units: ● Address 29: bits 0 to 15	0001 - mbar 0002 - Bar 0003 - Psi
16 bit Device Pressure Datum Type: ● Address 2E: bits 0 to 15	0000 - Gauge 0001 - Absolute 0002 - Sealed Gauge
Reading a Memory Location
To get the data, read out 3 bytes:	● Byte 1 = Status byte (If not required, ignore) ● Byte 2 = NVM Memory data (bits 15:8) ● Byte 3 = NVM Memory data (bits 7:0) Example: Serial number read: 71652 00Hex = LSB = 17E4 01Hex = MSB = 1
Reading the Pressure Data To read a register use the memory location as the command
To initiate a pressure reading use one of the following commands:	● A single reading command: AAhex ● An average of 4 consecutive readings : ADhex ● An average of 8 consecutive readings : AEhex
To acquire pressure data read 4 bytes:	● Byte 1 = Status byte (ignore) ● Byte 2 = Sensor data (bits 23:16) ● Byte 3 = Sensor data (bits 15:8) ● Byte 4 = Sensor data (bits 7:0)

Note: data is only available once per issuance of a read command.

Below is an example of a 0 to 10 Bar absolute pressure range, the NVM would look like this:

• 2A (Zero pressure range) = 0000
• 2B (Zero decimal place) = 0000
• 2C (Full scale pressure range) = 000A
• 2D (Full scale decimal place) = 0000
• 29 (Pressure engineering units) = 0002
• 2E (Pressure datum type) = 0001

An example of typical calibration figures would look something like this:

• 24 (Zero calibration LSB) = 4563
• 25 (Zero calibration MSB) = 0019
• *When converted from HEX, 0019 4563 to decimal = 1656163
• 26 (Full scale LSB) = 4C8E
• 27 (Full scale MSB) = 00E6
• *When converted from HEX, 00E6 4C8E to decimal = 15092878

This, therefore, means that 0 Bar Absolute pressure = 1656163 and 10 Bar absolute pressure = 15092878 giving a span of 13436715 for 10 bar.