Editor’s note: I am pleased to bring you a really important new solution for industrial designers by Maxim Integrated. Authors Michael Jackson and Sean Long did an excellent job in outlining the important features of the Pocket IO as it relates to Industry 4.0
The fourth revolution in manufacturing and process automation, often referred to as Industry 4.0, will advance on the backbone of connected systems: sensors, actuators, and control systems, all linked through networks via the internet protocol. Sensor data will be analyzed to optimize manufacturing, predict failures, schedule maintenance and automatically replenish inventory. This poses a considerable challenge for programmable logic controller (PLC) design engineers who are required to pack more functionality into enclosures that keep getting smaller. Higher input/output (I/O) density and smaller form factors also add to the design challenge in another basic way: the system must be more power efficient than ever to prevent the PLC from overheating, especially in an application where fans and vents are generally not acceptable.
ADDRESSING THE CHALLENGE
Fortunately, a new solution is available which leverages the latest chip integration technology. Combining multiple discrete functions in a single IC provides system designers with significant advantages in size, power consumption and cost. Maxim Integrated’s groundbreaking Pocket IO PLC Development Platform (Figure 1 and 2) uses analog integration to enable lower heat dissipation and faster throughput than ever before, in an extremely compact footprint of less than ten cubic inches.
The Pocket IO full block diagram
Pocket IO Functional Blocks
Pocket IO features a complete analog input signal chain consisting of a multi-channel 24-Bit sigma-delta ADC, a 36V precision, low-power operational amplifier, and an ultra-precision voltage reference. The analog output signal chain consists of a 16-bit, low-power, buffered output, rail-to-rail DAC with SPI Interface, and a 36V precision, low-noise, wide-band amplifier.
Pocket IO uses a multichannel serializer (Figure 3) to translate, condition, and serialize the 24V digital outputs of sensors and switches to the 5V, CMOS-compatible levels required by system microcontrollers.
MAX31913 8-Channel Serializer
- Higher density I/O boards are possible
- Lowest power/heat dissipation available
- Isolation is required on only three channels
- SPI ports can share the same three isolated by daisy chaining multiple serializers
Further space and power savings are achieved in the digital output drivers through the use of the octal high speed, high-side switch and push-pull driver (Figure 4).
- Best-in-class RON , to reduce heat dissipation
- Safe discharge of any inductive loads through the use of Maxim’s “Safe DeMag” technology.
- High speed switching up to 200kHz
MAX14913 Switch/Push-Pull Driver
The CMOS digital isolator (Figure 5) isolates the input channels, negating the need for inefficient optocouplers.
MAX14130 Digital Isolator
- Ideal for use in electrically noisy applications
- Enables direct interfacing to low voltage ASIC’s and micros, from 1.8V to 5.5V
- Small form factor (6mm x 5mm QSOP) with 1kVRMS isolation
Four IO-Link ports allow two-way communication with smart sensors, via the IO-Link master transceiver (Figure 6).
MAX14824 IO-Link Master Transceiver
Key benefits include:
- Scalable up to 16 master devices on a single bus, reducing component count
- Eases host controller processing by checking C/Q data line polarity and inverting
- Two integrated LDO's save board space
The DC motor driver (Figure 7) provides a small, low-power, simple solution for driving and controlling brushed DC motors and relays with voltages between 4.5V and 36V.
MAX14870 Motor Controller
- Very low driver on-resistance reduces power dissipation
- Charge-pump-less design reduces complexity and solution size
RS-485 ROBUST COMMUNICATIONS
Robust communication is provided by the dual voltage (3.3V and 5V), high speed RS-485/RS- 422 transceiver with the high ±35kV ESD protection (Figure 8).
MAX14783E RS-485 Robust Communications
The DC–DC voltage conversion stage of the Pocket IO further demonstrates potential power and space savings. The high-voltage, high-efficiency, iso-buck DC–DC converter provides isolated power up to 3W. The device operates over a wide 4.5V to 42V input and uses primary-side feedback to regulate the output voltage. The low-resistance, integrated MOSFETs ensure high efficiency at full load while simplifying the PCB layout. The high-efficiency, high-voltage, synchronous step-down DC–DC converter with integrated MOSFETs (Figure 9) operates over a 4.5V to 60V input voltage range.
- Low RDSON and power-MOSFET synchronous rectification increase efficiency by as much as 10% over asynchronous solutions (> 90% peak efficiency)
- Small, 3mm × 2mm, TDFN package integrates high-side and low-side power MOSFETs to considerably reduce overall solution size by eliminating bulky Schottky diodes
- Internal power MOSFETs, built-in compensation, and preprogrammed output options significantly reduce solution cost by requiring as few as five external components.
Maxim’s Pocket IO PLC Development Platform provides designers and industrial engineers the flexibility to experiment, to find the best solution for reduced power dissipation and small form factors in PLC designs.
About the authors
Michael Jackson has over 20 years’ professional experience as an Analog IC Design Engineer. He lectures in Electronics and Computing at Galway-Mayo Institute of Technology, Ireland and holds a MSEE from Dublin City University, Ireland.
Sean Long is Director, Marketing & Applications for the Industrial and Medical Measurement Business at Maxim Integrated. Sean joined Maxim in May 2012. He has a BSc Electrical and Electronic Engineering from Aston University, Birmingham UK.
MAXREFDES150 Pocket IO PLC Development Platform.