Industrial Shields M-Duino alternative: MPINO and MPAINO compared

Isolated inputs next to the relays

The M-Duino 19R has 8 relays and 6 inputs: 2 opto-isolated digital inputs for 5–24 Vdc signals and 4 inputs that read either analog 0–10 V or digital. The MPINO-8A8R-S has the same 8 relays with 8 opto-isolated digital inputs, wired NPN or PNP through a shared common, and 4 separate analog inputs on top.

For more points, the MPINO-16A16R carries 16 inputs and 16 relays, and the modular MPAINO line goes from 8 inputs and 8 relays up to 64 and 64 on one ATmega2560 controller. Industrial Shields covers larger counts with bigger models such as the M-Duino 38R (16 relays) and 57R (23 relays). Its M-Duino 21 has no relays at all; its outputs are opto-isolated digital and analog/PWM.

Current loops, 0–10 V and temperature

The M-Duino 19R and 21 work on a 0–10 V scale in both directions. Their analog inputs read 0–10 V at 10 bits, and their analog outputs drive 0–10 V setpoints, which the MPINO-8A8R-S cannot do. For a 4–20 mA loop, the FAQ on both product pages says to add a precision shunt resistor (500 Ω turns 20 mA into 10 V) and scale the reading in code.

MPINO -S boards take the loop directly. The MPINO-8A8R-S reads 4–20 mA as shipped through a 250 Ω input, 0–5 V with a jumper removed, or 0–10 V as an order option, and it reads two 10 kΩ NTC thermistors from −40 to 120 °C. The MPINO-8A8T-S, MPINO-8A4R-SU, MPINO-16A16R and MPINO-16A8R8T can also be ordered with analog inputs changed to 0–10 V. If you need analog outputs on an MPINO, the MPINO-16A8R8T has two 0–5 V outputs alongside 8 relays and 8 transistor outputs.

Ethernet, SD card and clock

Every M-Duino model has Ethernet, and the 19R and 21 pages also list a real-time clock and a microSD slot. That makes M-Duino the better fit for logging to an SD card, running Modbus TCP from the controller, or maintaining the program remotely over Ethernet.

No MPINO or MPAINO board has an Ethernet port or an SD slot, and the MPINO-8A8R-S does not support SPI devices at all. A real-time clock is the separately sold DS3231 module on the I²C connector. The separately sold M-ETHER converter puts an RS-232 or RS-485 port on a Modbus TCP network.

Two board packages, plus ladder

Both are Arduino IDE products with their own board packages, so sketch structure, Wire and Serial code carry over. Industrial Shields references its terminals by name (I0_x, Q0_x, A0_x, R0_x) and handles Modbus RTU and Modbus TCP with its Arduino libraries. The ILOGICS one is the ARDUINO SDK. In it, Modbus RTU master and slave are built-in commands, and the pins are plain Arduino numbers listed in each model's manual.

MPINO STUDIO2 adds a second way to program the same board. Ladder tabs and Arduino C/C++ tabs sit in one project and share PLC-style memory (P, M, D, T, C and R), and the ladder runs inside your loop(). STUDIO2 includes a Modbus RTU slave and an LS Cnet slave for HMI connection. It is free and covers every MPINO and MPAINO model. The Arduino PLC page shows how a project splits work between rungs and code.

Uploading differs too. M-Duino uploads over USB, and its product page notes that Ethernet allows remote maintenance. The MPINO-8A8R-S uploads over USB only through the MP Download Cable, which has the USB-to-serial converter built in.

Certification, buying and support

Industrial Shields lists CE and RoHS for the 19R, and ETL for the M-Duino 21, 42 and 58. If an installation in North America requires ETL certification, start with one of those three.

ILOGICS has no UL or ETL listing. Its CE Declaration of Conformity under the EMC Directive covers MPAINO-8A8R, MPAINO-16A16R, MPAINO-24A24R and MPAINO-32A32R, their -X3F2 versions and the matching MPA ladder PLCs; MPINO models are not covered.

Industrial Shields sells through its online shop, and its distributor page lists a distributor in the United States. ILOGICS has no US distributor. It sells direct from its online store with PayPal checkout in USD, ships from Korea, and quotes orders of 10 units or more through the quote form, where prepaid bank transfer in USD is also accepted. Boards carry a one-year warranty from the delivery date, and engineers answer technical email on weekdays, 09:30–17:30 Korea time.

When M-Duino is the better choice

• The controller needs Ethernet, an SD card or a real-time clock on board.

• You drive 0–10 V setpoints from analog outputs.

• You need an ETL certified controller (M-Duino 21, 42 or 58).

• You want an original Arduino Mega inside.

• You also want ESP32 or Raspberry Pi based PLCs from the same supplier.

• You want field-tested example projects with code, such as those in Industrial Shields' PLC Solution Library.

When MPINO or MPAINO is the better choice

• You want 8 or more opto-isolated NPN or PNP inputs next to 8 or more relays on one board.

• You wire 4–20 mA transmitters or NTC thermistors straight to the terminals (MPINO -S).

• You want ladder and Arduino C/C++ in one free tool.

• You need up to 64 inputs and 64 relays on one controller (MPAINO).

• Your HMI connects over RS-485 with Modbus RTU or LS Cnet.

Porting an M-Duino sketch

Replace the I0_x, Q0_x and R0_x names with the pin numbers in the MPINO-8A8R-S manual: inputs are D0 to D7 and relays are D32 to D39 on that board, and the RS-485 port is Serial1. Call analogReference(EXTERNAL) in setup() before reading the analog inputs. Code for Ethernet, the SD card and the on-board RTC has no direct MPINO equivalent; use the DS3231 module for timekeeping and M-ETHER if the network side must stay.