DEMO MANUAL DC2227A
LT3669-2
IO-Link Device with Multiple Sensors
Description
Demonstration circuit 2227A is a complete IO-Link
®
de-
vice built using the
LT
®
3669-2
to implement an IO-Link
v1.1 physical interface (PHY). The IO-Link stack protocol
runs on an Atmel ATmega microcontroller which connects
to LT3669-2’s logic IO-signals to communicate with an
IO-Link master via the CQ1 transceiver.
An LTC2997 temperature sensor, an opto-coupler (light
barrier) and a pushbutton demonstrate IO-Link device
functionality and master-slave interoperability.
A 28V/100mA light bulb connected to LT3669-2’s second
driver (Q2) demonstrates its high current driving capabili-
ties. All low voltage circuitry is supplied by the LT3669-2’s
integrated buck and LDO for high efficiency.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2227A
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. IO-Link is a registered trademark of PROFIBUS User Organization
(PNO). All other trademarks are the property of their respective owners.
performance summary
SYMBOL
L+
V
BUCK
V
LDO
PARAMETER
Input Supply
LT3669-2's Buck Output Voltage
LT3669-2's LDO Output Voltage
Specifications are at T
A
= 25°C, V
L
+ = 24V
CONDITIONS
MIN
18
3.8
3.135
4
3.3
TYP
MAX
36
4.2
3.465
UNITS
V
V
V
BoarD photo
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DEMO MANUAL DC2227A
Quick start proceDure
Additional Hardware and Software Requirements
To operate the DC2227A demo circuit in IO-Link mode,
additional hardware and software are required:
•
PC running Windows XP or later with Ethernet Card.
Alternatively a USB-to-Ethernet adaptor can also be used
•
LTC IO-Link Master Demo Circuit DC2228A
•
DC2228A Control Tool Software
•
PoE Injector or 24V Power Supply
•
DC2227A IODD Files (COM2 and COM3)
Set-up Preparation (See Figures 1 and 2)
1. Download and install the DC2228A Control Tool soft-
ware from:
www.linear.com/demo/DC2228A
2. Connect the DC2228A to power and the host com-
puter. Refer to the DC2228A demo manual for detailed
information about the different configuration options
to supply the DC2228A and interface it to the PC.
3. Using a 3-wire IO-Link cable of up to 20m in length
with M12 connectors, plug the male terminal to one
of the 8-ports of the DC2228A (for example port 2 like
in Figure 1) and the female terminal to the DC2227A.
4. Run the DC2228A Control Tool on the PC and connect
to the DC2228A. See the DC2228A demo manual for
detailed information of how to select the DC2228A as
the master, configure the IP parameters and establish
communication between the host computer and the
master.
Operation in IO-Link Mode (See Figures 1 and 2)
5. Download the DC2227A IODD files from:
www.linear.com/demo/DC2227A
6. Click on the “Select Device” button and import the
IODD files by selecting the downloaded xml files and
then clicking on the “Import” button (one at a time).
Operation in COM2
7. Click on the “Select Device” button again, this time
making sure the correct port is selected. Use the fol-
lowing IODD file:
TEConcept_GmbH-65538-<YYYYMMDD>-IODD1.1.xml
8. If the device is off, switch it on, enabling the L+ sup-
ply of the connected master’s port by pressing the
“Power ON” button keeping the light barrier open
during power-up. If the device was already powered on
coming from COM3 mode, power cycle it keeping the
light barrier open to restart the device in COM2 mode.
See the Light Barrier section for more information.
9. Start IO-Link communication by pressing the “IO-Link”
button. The “Min. Cycle Time” is set to 20ms.
10. If a different IODD file is to be selected, stop IO-Link
communication first by pressing the “Inactive” button
to revert the DC2227A into SIO mode.
Operation in COM3
11. Click on the “Select Device” button again making sure
the correct port is selected. Use the following IODD
file:
TEConcept_GmbH-65539-<YYYYMMDD>-IODD1.1.xml
12. If the device is off, switch it on, enabling the L+ sup-
ply of the connected master’s port by pressing the
“Power ON” button keeping the light barrier closed
during power-up. If the device was already powered on
coming from COM2 mode, power cycle it keeping the
light barrier closed to restart the device in COM3 mode.
See the Light Barrier section for more information.
13. Start IO-Link communication by pressing the “IO-Link”
button. The “Min. Cycle time” is set to 800µs.
14. If a different IODD file is to be selected, stop IO-Link
communication first by pressing the “Inactive” button
to revert the DC2227A in SIO mode.
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DEMO MANUAL DC2227A
Quick start proceDure
Figure 1. Recommended Set-up for Operating DC2227A in IO-Link Mode
Figure 2. Control Tool for Connecting DC2227A to DC2228A
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DEMO MANUAL DC2227A
aDDitional information
Operation in SIO Mode
The device can also operate in SIO mode. In this mode,
no IO-Link communication takes place either because the
master connected to the device is in the “Inactive” mode
and it only supplies power to the device, or because there
is no master connected to the device in which case the
device is powered by a 24V supply. In SIO mode, the
DC2227A reacts to the status of the light barrier as follows:
•
If the light barrier is open, then drivers CQ1 and Q2
actively pull low. Since the onboard light bulb is con-
nected between Q2 and ground, it is therefore turned
off.
•
If the light barrier is closed (by placing a piece of paper
in its gap), CQ1 and Q2 actively pull high and the light
bulb attached to Q2 turns on.
Temperature Sensor Configurations
In IO-Link mode, the DC2227A reports cyclically to the
master (and thus to the PC Control Tool) the temperature
measured by the on-board LTC2997. In order to measure
temperature the LTC2997 uses an NPN configured as a
diode. The NPN can be either on-chip, on PCB (Q1) or
remote. Refer to the Connectors and Jumpers section for
detailed information on how to choose the NPN.
Microcontroller ADC’s Offset Correction
The 12-bit ADC of the Atmel microcontroller samples
both, the precise 1.8V reference voltage (V
REF
) and the
VPTAT outputs of the LTC2997 to report the temperature
in Celsius to the IO-Link master. The temperature is then
calculated using a ratiometric measurement. The µC’s
ADC is specified to have offsets from –40 to 40 LSBs.
The temperature equation is:
100• T(°C)
=
ADC7 – OFFSET
• 45000 – 27315
ADC4 – OFFSET
ADC7 is the ADC’s code for the VPTAT output and ADC4
the code for the precise 1.8V V
REF
. OFFSET is the ADC’s
offset (in LSB) parameter that can be set using the control
tool (default is 0 LSB). In order to improve the accuracy
of the temperature reading, a calibrated thermometer can
be used to measure the temperature close to the LTC2997
and then the ADC Offset parameter can be set to the value
(after several tries) that minimizes the error between the
temperature reported by the Control Tool and that given
by the calibrated thermometer.
Event Generator
The DC2227A is also equipped with a pushbutton to
simulate events generated by IO-Link devices to inform
IO-Link masters of requests that require special attention.
Light barrier
The light barrier offers many ways to interact with the
device. It starts the device in COM3 mode if it is closed
during power-up or in COM2 mode if left open. In IO-Link
mode, its status is reported live on the PC control tool and
in SIO mode its status is directly coupled to the CQ1 and
Q2 drivers, thus allowing the user to operate the light bulb.
Light bulb
A 28V/100mA light bulb connects between Q2 and ground
and serves to show the high current driving capability of
the line drivers. It takes about 240ms to be turned on fully
by the pulsing mechanism of the LT3669-2. To prevent data
loss in IO-Link mode, driver Q2 is only enabled in between
IO-Link telegrams. To turn it on and off from the control
tool (in COM2 only) simply press the “Turn On” and “Turn
Off” buttons within the light bulb section. In SIO mode,
regardless on the IODD file chosen, the light bulb can be
switched on and off by interacting with the light barrier.
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DEMO MANUAL DC2227A
aDDitional information
Connectors and Jumpers
The board has the following connectors:
Table 1. Connectors and Jumpers Overview
Name Type
J1
J2
J3
J4
J5
J6
J7
J8
J9
Connector
Jumper
JTAG
Jumper
Jumper
Jumper
Connector
Jumper
Form
Pin-2
M12
Pin-2
Header 8
×
2_2mm
Pin-6
Pin-4
Header10
×
2
Pin-3
Pin-3
Comment
Atmel µC Flash Erase
IO-Link Signals (L+, L–, CQ1, Q2)
LT3669-2 EN/UVLO Pin
Eval Board DC1733
SPI Interface
Sensor Selection
JTAG Programming
VDD3 Select
Reset Select
Jumper J3
Jumper J3 enables/disables the on board LT3669-2 (which
also generates the internal 3.3V supply rail). Close this
jumper (default position) to use the onboard LT3669-2
as the IO-Link PHY (it will start up for L+ voltages above
14.8V). Leave this jumper open if the external DC1733A-B
board is used (via the J4 connector) as the IO-Link PHY
instead.
Connector J4
J4 is for connecting an external DC1733A-B demo circuit
bypassing the on-board LT3669-2. This connection allows
access to more signals from LT3669-2. Connect jumper
J3 from DC1733A-B pin-to-pin to jumper J4 on this board.
Table 3 identifies each pin.
Table 3. Connector J4 Pinout
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Function
TXD2
TXEN2
TXD1
TXEN1
RXD1
GND
WAKEn
GND
SC2n
SC1n
GND
RST_n
V
DD(EXT)
GND
TP33
SYNC
Comment
DC1733A-B Driver Input (Q2)
DC1733A-B Driver Input (Q2)
DC1733A-B Driver Input (CQ1)
DC1733A-B Driver Input (CQ1)
DC1733A-B Receiver Output (CQ1)
DC1733A-B Ground
DC1733A-B Wake-Up Output
DC1733A-B Ground
DC1733A-B Driver Short Circuit Output (Q2)
DC1733A-B Driver Short Circuit Output (CQ1)
DC1733A-B Ground
DC1733A-B POR Reset Output
DC1733A-B LDO’s Output (3.3V)
DC1733A-B Ground
DC1733A-B Buck Output (5V)
DC1733A-B Buck Oscillator Synchronization Input
Jumper J1
Jumper J1 sets the Erase/PB12 pin of the microcontroller
to VDD3 (3.3V). By default the J1 header is not populated.
For details about the Erase/PB12 pin see the ATSAM31S2AA
microcontroller data sheet.
Connector J2
Connector J2 is a 5-pin M12 male connector. Plug a
standard industrial sensor cable to this connector to sup-
ply and communicate to the DC2227A using an IO-Link
master. Table 2 shows the internal pin assignments to the
LT3669-2 IO-Link PHY:
Table 2. Connector J2 Pinout
M12 Pin
1
2
3
4
5
LT3669-2’s Pin
L+
Q2
GND
CQ1
Not Connected
Comment
DC2227A Input Supply (24V)
LT3669-2 Second Driver
DC2227A Ground Node
LT3669-2 Transceiver (IO-Link)
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