Table of Contents
MNET-8A8T
MNET-8A8T is a communication slave I/O device that allows a master device such as a PC, HMI, or PLC to read digital inputs and control transistor outputs over a communication link.
Provides 8 digital inputs and 8 SINK transistor outputs as standard. Select Modbus RTU Slave or LS Industrial Systems Cnet Slave when ordering.
This product does not accept downloaded user programs. The master device controls I/O by reading or writing addresses on MNET-8A8T.
Product Specifications
| Category | Quantity | Terminals / Addresses | Specifications |
|---|---|---|---|
| Product role | - | - | Communication slave I/O No user program |
| Power | - | +24V, GND, F.G | DC 24V power terminals |
| Digital inputs | 8 points (Isolated) | IN0~IN7 Modbus 0~7 Cnet P0000~P0007 | DC 5~24V NPN/PNP inputs Optocoupler isolation 4 points/1COM |
| Transistor outputs | 8 points (Isolated SINK) | OUT0~OUT7 Modbus 32~39 Cnet P0032~P0039 | Max. DC 60V, 1A Optocoupler isolation Use external load power |
| Communication protocol | Order option | Modbus RTU Slave LS Industrial Systems Cnet Slave | Select one of the two protocols when ordering |
| Communication Channels | 1 channel each | RS-232 RS-485 UART | Use the port wired to the master device |
| I²C | 1 channel | SDA, SCL | CPU module terminals |
| Internal power | - | +5V, GND | Int VCC terminals |
| Mounting | - | - | 35mm DIN rail |
Communication terminals
Identify the CPU module terminals for the communication interface used to connect the master device.
| Communication interface | Product terminal labels |
|---|---|
| RS-232 | TX, RX, GND |
| RS-485 | 485+, 485− |
| UART | TXD, RXD, GND |
Digital inputs
See the one-channel digital-input check before wiring for the first time. →
| Group | Input contacts | Communication address | Input configuration |
|---|---|---|---|
| Input 0~3 group | IN0~IN3 | Modbus 0~3 Cnet P0000~P0003 | 4 isolated digital inputs DC 5~24V NPN/PNP inputs |
| Input 4~7 group | IN4~IN7 | Modbus 4~7 Cnet P0004~P0007 | 4 isolated digital inputs DC 5~24V NPN/PNP inputs |
Each group of 4 inputs shares one COM terminal. The master device can read input states with Modbus RTU FC02 (Read Discrete Inputs).
Transistor outputs
See the one-channel SINK transistor-output check before wiring for the first time. →
| Output contacts | Communication address | Output power | Output configuration |
|---|---|---|---|
| OUT0~OUT7 | Modbus 32~39 Cnet P0032~P0039 | Ext Vin+ Ext Vin− | 8 isolated SINK transistor outputs Max. DC 60V, 1A |
The output terminal block comprises OUT0~OUT7 and the external load power terminals Ext Vin+ and Ext Vin−. Its structure differs from the COM terminals of relay outputs.
In Modbus RTU, read output states with FC01 (Read Coils) and control outputs with FC05 or FC15.
Use an external load power supply. Use back-EMF protection such as a diode, TVS, or snubber for inductive loads including relays, solenoids, and motors.
Basic I/O communication addresses
| Category | Contact | Modbus RTU internal address (Decimal) | LS Industrial Systems Cnet | HMI DEC | Read / Write |
|---|---|---|---|---|---|
| Input | IN0~IN7 | 0~7 | P0000~P0007 | 10001~10008 | Read |
| Output | OUT0~OUT7 | 32~39 | P0032~P0039 | 00033~00040 | Read / Write |
| State | - | 1000 | M0000 | - | - |
The HMI DEC address is a 1-based display address entered on the HMI screen. Use the internal addresses in the table in Modbus RTU frames.
DIP switch settings
The baud-rate DIP switch has 3 bits; switches 1·2·3 have values 4·2·1 respectively. The leftmost switch is the most significant bit.
| Set value | Baud rate | Switch 1 | Switch 2 | Switch 3 |
|---|---|---|---|---|
| 0 | 9,600bps | OFF | OFF | OFF |
| 1 | 14,400bps | OFF | OFF | ON |
| 2 | 19,200bps | OFF | ON | OFF |
| 3 | 28,800bps | OFF | ON | ON |
| 4 | 38,400bps | ON | OFF | OFF |
| 5 | 57,600bps | ON | OFF | ON |
| 6 | 76,800bps | ON | ON | OFF |
| 7 | 115,200bps | ON | ON | ON |
The slave-address DIP switch has 4 bits; switches 1·2·3·4 have values 8·4·2·1 respectively. Form the desired address by adding the values of the selected switches.
| Setting example | Switch 1 (8) | Switch 2 (4) | Switch 3 (2) | Switch 4 (1) |
|---|---|---|---|---|
| Address 0 | OFF | OFF | OFF | OFF |
| Address 1 | OFF | OFF | OFF | ON |
| Address 5 | OFF | ON | OFF | ON |
| Address 10 | ON | OFF | ON | OFF |
| Address 15 | ON | ON | ON | ON |
Set the DIP switches with power off. The master device's baud rate, data bits, parity, and stop bits must match the communication settings of the delivered product.
Optional modules
| Code | Function | Points per module | Maximum configuration | Value format |
|---|---|---|---|---|
| X | Analog inputs | 4 points | X~X5, up to 20 points | 15bit, 0~32,767 NTC mode: temperature ×10 |
| F | PT100Ω temperature sensor input | 4 points | F~F5, up to 20 points | Temperature ×10 |
| Y | Analog outputs | 3 points | Y~Y4, up to 12 points | 16bit, 0~65,535 |
| K | High-speed pulse outputs | 6 points | K~K2, up to 12 points | WIDTH fixed at 65,535 Duty 0~65,535 |
The X module offers selectable DC 0~5V, DC 0~10V, 0~20mA, or NTC inputs. Connect a 2-wire or 3-wire PT100Ω sensor to the F module. The Y module offers selectable DC 0~5V, DC 0~10V, or 0~20mA outputs. The K module outputs DC 5V pulses at up to 1MHz.
Configure analog inputs (X) and PT100Ω inputs (F) for a combined maximum of 20 points, and analog outputs (Y) and high-speed pulse outputs (K) for a combined maximum of 12 points. You cannot order a configuration that simply adds the maximum point count of every module.
Options are assembled and shipped in the selected configuration; users cannot add or remove I/O or optional modules. Also see MNET Series option configuration guide.
Products with optional modules are custom-built, so exchanges or refunds may be difficult.
Interpreting option values
- X analog input values range from 0~32,767. Interpret them according to the selected input mode.
- X in NTC mode and F PT100Ω inputs transmit temperature multiplied by 10. For example, a received value of 213 means 21.3℃.
- Y output settings range from 0~65,535. Use them according to the selected output mode.
- K has a fixed WIDTH of 65,535 and outputs pulses from a Duty setting of 0~65,535. Contact us when ordering if you need to change the frequency or output pulse count.
Option module communication addresses
Use the address ranges below that correspond to the installed optional modules. The slave-address DIP switch selects the station address of the product to communicate with; the addresses in this table select items to read or write within that product.
| Module | channel | Modbus RTU internal address (Decimal) | LS Industrial Systems Cnet |
|---|---|---|---|
| X1 | 0~3 | 2000~2003 | D0000~D0003 |
| X2 | 4~7 | 2004~2007 | D0004~D0007 |
| X3 | - | 2008~2011 | D0008~D0011 |
| X4 | - | 2012~2015 | D0012~D0015 |
| X5 | - | 2016~2019 | D0016~D0019 |
| Y1 | 0~2 | 2020~2022 | D0020~D0022 |
| Y2 | 3~5 | 2023~2025 | D0023~D0025 |
| Y3 | 6~8 | 2026~2028 | D0026~D0028 |
| Y4 | 9~11 | 2029~2031 | D0029~D0031 |
| F1 | 0~3 | 2040~2043 | D0040~D0043 |
| F2 | 4~7 | 2044~2047 | D0044~D0047 |
| F3 | - | 2048~2051 | D0048~D0051 |
| F4 | - | 2052~2055 | D0052~D0055 |
| F5 | - | 2056~2059 | D0056~D0059 |
| K1 | PWM0~PWM5 | 2060~2065 | D0060~D0065 |
| K2 | PWM6~PWM11 | 2066~2071 | D0066~D0071 |
The confirmed separate addresses for the X module in NTC mode are as follows.
| Module | Modbus RTU internal address (Decimal) | LS Industrial Systems Cnet |
|---|---|---|
| X1 NTC | 2080~2083 | D2080~D2083 |
| X2 NTC | 2084~2087 | D2084~D2087 |
The Cnet addresses for NTC are D2080~D2087. Enter these addresses using their own notation, distinguishing it from other option addresses.
Communication startup sequence
- Verify that the ordered product's communication protocol matches the master device.
- Turn off power and wire the required RS-232, RS-485, or UART port.
- Set the baud-rate and slave-address DIP switches.
- Match the master device port, baud rate, data bits, parity, stop bits, and target slave address to the delivered product settings.
- Check wiring and settings, then turn on the power.
- Read the first input to check communication. The Modbus RTU internal address is
0and the LS Industrial Systems Cnet address isP0000. - Verify that the load is safe for an output test, then control the first output. The Modbus RTU internal address is
32and the LS Industrial Systems Cnet address isP0032. - After verification, apply all required addresses in order.
