ModBus RTU IO Module

DAT3012

DAT3012 ModBus RTU IO Module.
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Modbus RTU IO Module DAT3012

• ModBus RTU Slave.
• 2 Analog Isolated Inputs.
• 2 Analog Isolated Outputs 4-20mA.
• 4 Digital Isolated Inputs.
• 3 Relays.
• All way isolation.
General Description

The DAT3012 Modbus RTU I/O Module is a flexible input-output device that combines universal analog inputs, analog outputs, digital inputs, and relay outputs with an isolated RS-485 Modbus RTU slave interface. It can acquire signals from voltage, thermocouples, RTDs, resistance, potentiometers, and current and retransmit them as isolated analog outputs while publishing data over a Modbus network.

I/O summary: 2 universal analog inputs, 2 isolated analog outputs (4–20 mA / 0–20 mA), 4 digital inputs (up to 3 kHz), and 3 SPST relay outputs rated up to 2 A.

The analog input type is software-selectable and can be configured remotely via Modbus and the free DAT3000-10000 software. This makes the DAT3012 an ideal choice as an isolated Modbus analog input card, an isolated 4–20 mA output module, a digital input counter, or a relay output driver.

Complete all-way galvanic isolation is provided between inputs, outputs, power supply, and RS-485 port, ensuring safe and reliable operation even in harsh industrial environments.

INPUT OUTPUT POWER SUPPLY
mV, Volts, mA, 4 Digital Inputs. 2 X Current 4-20mA. Power Supply Voltage 18-30Vdc
RTD, Resistance, Potentiometer,Thermocouples. 3 SPST Relays. Reverse polarity protection 60Vdc
CURRENT CONSUMPTION CONFIGURATION ISOLATION
Between 30 and 100 mA PC Programmable Between Input/Output/RS485/Power Supply 1500Vac.
EMC HOUSING TEMPERATURE
For Industrial environments Material self-extinguishing Operating Temperature 14°F +140°F -10°C +60°C
Immunity EN 61000-6-2 Dimensions W x H x T 4" x 4 3/4" x 3/4" Storage Temperature -40°F +185°F-40°C +85°C
Emission EN 6100-6-4 100 x 120x x 22.5 mm UL Operative Temperature 14°F +104°F -10°C +40°C
Weight 3 oz 90 g
DAT3012 Datasheet
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Applications
Specifications
Drawings
DAT3012 User Guide
ModBus Analog Input Modules
ModBus Analog Output
Application Note

User Instructions

Before installing the DAT3012, please read the “Installation Instruction” section. If the DAT3012 configuration is unknown, with DAT3012 switched off, connect the INIT terminal to the GND terminal (ground), reconnect the power and the DAT3012 will have the default settings (refer to the User Guide of the DAT3012). Connect the serial bus, analog, and digital inputs and outputs as shown in the “Wiring” section. The green “PWR” LED remains ON while power is connected, the yellow LED “STS” changes state and depends on the working condition of the DAT3012: refer to the "Light Signaling" section to verify the device working state. To perform configuration and calibration operations, read the instructions in the User Guide of the DAT3012. To simplify handling or to replace the DAT3012, it is possible to remove the wired terminals even with the device powered.
Specifications
Input type: Min  Max 
Current
20 mA -20 mA 20 mA
Voltage
100 mV -100 mV 100 mV
10 V -10 V 10 V
Thermocouple
J Type Thermocouple -346℉ 2192℉
-210℃ 1200℃
K Type Thermocouple -346℉ 2498℉
-210℃ 1370℃
R Type Thermocouple -58℉ 3200℉
-50℃ 1760℃
S Type Thermocouple -58℉ 3200℉
-50℃ 1760℃
B Type Thermocouple 752℉ 3317℉
400℃ 1825℃
E Type Thermocouple -346℉ 1832℉
-210℃ 1000℃
T Type Thermocouple -346℉ 752℉
-210℃ 400℃
N Type Thermocouple -346℉ 2372℉
-210℃ 1300℃
RTD 2, 3 Wire
Pt 100 -328℉ 1562℉
-200℃ 850℃
Pt 1000 -328℉ 392℉
-200℃ 200℃
Ni 100 -76℉ 356℉
-60℃ 180℃
Ni 1000 -76℉ 302℉
-60℃ 150℃
Resistance 2,3 Wires
Low 0 Ω 100 Ω
High 0 Ω 2000 Ω
Accuracy
mV, Volt, mA, Pot, RTD, Resistance ±0.05% f.s.
Thermocouple > of ±0.05% f.s. or 5uV
Linearity.
mV, Volt, mA ±0.05% f.s.
Pot, RTD, Resistance ±0.1% f.s.
Thermocouple ±0.2% f.s.
Excitation Current. RTD, Res, Pot. Typical 0.7 mA
Line resistance influence
RTD, Res 3 wires 0.05 f.s.%/Ω
mV, T/C 0.8 uV/Ω
CJC error ± 1.8 ℉ ± 1 ℃
Input Impedance
mV, Thermocouple 10 MΩ
mA 22 Ω
Thermal Drift
Inputs Full Scale ±0.01% f.s./℉ ±0.01% f.s./℃
Thermal Drift CJC
Full Scale ±0.02% f.s./℉ ±0.02% f.s./℃
Number of Channels 4 Channels
Pulse Counters 32 bit 4 up to 3 kHz
Input Voltage Off State 0-3V
On State 10-30V
Input Impedance 4.7 KΩ
Signal type Min Max
0 mA 20 mA
Accuracy ±0.05% f.s.
Linearity ±0.05% f.s.
Thermal Drift ±0.01% f.s.
Load resistance < 500Ω
Auxiliary Voltage 12 Volts @ 20 mA
Sample Time from 10 to 90% 500 ms
Warm up time 3 minutes
Digital Output
Number of outputs 3
Max Switching power 2 A @ 250 Vac 2 A @ 30 Vdc
Minimum Load 5 Vdc, 10mA
Dielectric Strength
Between Contacts		 1000 Vac 50 Hz 1 Min
Dielectric Strength
Between Coil and Contacts		 1000 Vac 50 Hz 1 Min
Baud Rate Up to 115.2 Kbps
Maximum Distance 4000 ft 1.2 Km
Power supply voltage 18 .. 30 Vdc
Reverse polarity protection 60 Vdc max
Current Consumption 100 mA
Power Supply
RS485
Analog input
Analog output
Digital Input
Relays
 1500Vac 50Hz, 1 Min
Operative temperature 14℉ to 140℉
-10℃ to 60℃
UL Operative temperature 14℉ to 104℉
-10℃ to 40℃
Storage temperature -40℉ to 185℉
-40℃ to 85℃
Humidity (not condensed) 0 to 90 %
Maximum Altitude 6500ft 2000m
Installation Indoor
Category of installation II
Pollution Degree 2
Weight 6 Oz
150 g.
Material Self-extinguish plastic
IP Rating IP20
Wiring size AWG 14-18
0.8÷2.1 mm²
Screw torque 0.8 N m
Mounting DIN rail standard EN-50022 and EN-50035
Dimensions H x" L x" T x"
H 100 mm L 120 mm T 22.5 mm
EMC For industrial environments
Immunity EN 61000-6-2
Emission EN 61000-6-4
Drawings

Channel A Analog Input

Universal input for the DAT3012 channel A

Channel B Analog Input

Analog input for DAT3012 channel B
Input. Channel A Channel B1
RTD 3 Wire 3 and 2 Compensation 1 13 and 11 Compensation 10
Potentiometer 6 and 4 Wiper 5 15 and 13 Wiper 14
mV Positive 2 Negative 3 Positive 11 Negative 12
Thermocouple Positive 2 Negative 3 Positive 11 Negative 12
Volts Positive 7 Negative 9 Positive 16 Negative 15
mA Positive 8 Negative 9 Positive 17 Negative 15
Common 3, 6, 9 12, 13
Connect the wiring to the correct input on each channel. The input reading will be displayed on Register 40027 for input A and 40028 for input B. Please note on channel A the Terminals 3, 6 and 9 are connected together. On channel B, 12 and 13 are connected to each other.

Digital input

Digital input for modbus RTU IO module DAT3012

Digital input


Common 18 
DI 0 Terminal 19
DI 1 Terminal 20
DI 2 Terminal 21
DI 3 Terminal 22
The ON signal is between 10-30 Vdc. The OFF flag is below 3 Volts. A signal needs to be supplied between Terminal 18 and the Digital input.

Analog Outputs

Analog output for Modbus RTU IO module DAT3012

Analog Outputs


Active Loop Passive Loop
Auxiliary Voltage Output Terminal D
Terminal E Load 0 Return Load 0 Return
Terminal F Load 1 Return Load 1 Return
Terminal G No Connection Ground
Active loop is when the DAT3012 supplies the Voltage to power up the outputs. Passive Loop is when a power supply is external to the DAT3012.

Relay Outputs

Relay outputs for Modbus RTU IO Module

Relay Outputs


Relay 0 Terminal K Terminal L
Relay 1 Terminal M Terminal N
Relay 2 Terminal O Terminal P
The DAT3012 is fitted with 3 similar relays with single pole single throw contacts.

Power Supply, RS-485 and Init

Power supply for the DAT3012
The DAT3012 ModBus Remote terminal unit is powered by 24 Vdc and can work with a tolerance between 18 and 30 Vdc. The ModBus RS485 signal is connected to terminal A and B. It is good practice to always use a shielded cable and earth the shield at one end of the coaxial cable.
If the DAT3012 configuration is unknown, with DAT3012 switched off, connect the INIT terminal to the GND terminal (ground), reconnect the power and the DAT3012 will have the default settings (refer to the User Guide of the DAT3012).

Power Supply, RS-485 and Init


Power Supply
18 -30 Vdc Terminal J Positive Terminal I Ground
RS-485
Terminal A D- Terminal B D+ Terminal C Ground
Init
Terminal H Init Terminal B Ground

Isolation Map

Galvanic Isolation layout for the Modbus RTU IO module DAT3012
The Analog and Digital inputs and Outputs are all isolated from the power supply and the RS485 ModBus communication port.

LED Signaling


LED Color State Description
PWR Green On
OFF
Blink		 Power On
Power Off
Watch-Dog Alarm
STS Yellow Off Correct operation
RX Red Blink
Off		 Receiving Data
No Data Receiving
TX Red Blink
Off		 Send Data
Not Send Data
I(n) Red On
Off		 Digital Input "n" On
Digital Input "n" Off
R(n) Red On
Off		 Digital Output "n" On
Digital Output "n" Off
The DAT3012 has LED indication for different conditions. The Green LED is for Power Indication of the ModBus RTU IO Module. The Yellow is for the correct operation. The RX and TX red indication indicates sending and receiving the RS485 ModBus communication. The I indication indicates that a Digital input has been seen and R Led is indicating the Relay output has been activated.

The ModBus RTU IO module DAT3012 is suitable for fitting on to an EN-50022 top hat DIN rail in the vertical position. For optimum operation follow these instructions: Install the DAT3012 side by side. However, it may be necessary to separate them by at least 5 mm in the following case: Avoid temperature exceeding 45°C. Make sure that sufficient air flow is provided for the DAT3012 ventilation slits. Avoid mounting above appliances generating heat. Fit the DAT3012 in the lower part of the panel. Avoid high vibration. Don't route conductors near power signal cables such as motors, induction ovens, inverters, also use shielded cable for connecting signals.

Applications Back to General Description
Application Note Modbus RTU Analog and Digital IO DAT3012.
Printed Version

Set Up the DAT3012.

  1. Connect 24 Vdc to I and J.
  2. Connect RS485 to A and B.
  3. Connect an Input to the Analog A. For this application note we have chosen the default setting of an RTD.
  4. To check the Digital Input Connect 24Vdc across DI_C and DI_1.
  5. Connect a Multimeter between terminal D and E to read the 4-20mA output.
  6. Connect a Multimeter to measure the output of the relay on Terminal K and L, which is Relay Output 0.
  7. If the communication parameters are unknown, short out the INIT connections H and I.
  8. Power up the DAT3012 Modbus RTU Slave.
It is advisable to use the DAT3580 to connect the DAT3012 to the PC. The advantage of using the DAT3580 is that it will isolate your PC from the DAT3012. The DAT3580 options are USB, Ethernet and RS232. If the DAT3580USB version is used, install the USB drivers. If the DAT3580MBTCP or the DAT3580GW are used, make sure the Ethernet parameters are compatible with the net and transmission of data over port 502 is allowed.
DAT3012 Modbus RTU Slave for analog and digital io

Set-up PC.

  1. Download the 3000-10000 Software from www.datexel.com download page.
  2. Close all other software.
  3. UnZIP the Modbus_3000_10000_setup software.
  4. Run the 3000-10000 software.
  5. To start the software click the English version.
Start page for the Modbus 3000-10000 software

Set Up Communication.

  1. The software should automatically select the correct comms port. It is possible to override the comms port or refresh if you change the physical port.
  2. Choose the correct Com port settings.
  3. Click Open Com. The Port Status will change to green.
  4. The default Baud rate is either written on the Label or 38400bps. If the INIT is shorted, the Baud rate will be 9600bps, RTU, Data Bit 8, Stop Bit1, Parity None.
Communication screen for the Modbus 3000-10000 software

Selecting the Modbus RTU IO Module DAT3012.

  1. The green light only indicates the port is open. Even if the settings are incorrect the light will turn green.
  2. Select Model and the drop down navigation will appear.
  3. Select DAT3012.
Selecting the DAT3012 Digital IO

Setting the Address of the DAT3012 Modbus Slave.

  1. Change the Address to connect to 1 or what is written on the label.
  2. Click "Read data" (Single poll).
  3. The screen should now display the below screen.
  4. If there is a function error, no CRC match, check Baud rate, RS485 connection or Modbus Slave Address.
  5. This needs to be fixed before further progress. If you have not used the INIT on terminals C and D, it is highly recommended that you do now. Then return to Communication set up and set the settings to 9600bps, RTU, Data Bit 8, Stop Bit1, Parity None.
  6. This will always be the correct setting unless it differs on the label.
Selecting Address 1 on the DAT3012

Reading the analog input on the DAT3012.

  1. Connect a sensor to the input terminals for chosen sensor, We have selected an RTD for this application note.
  2. Select the correct sensor from the drop down option under Input Type.
  3. Click the Write button.
  4. Click the Read data button.
  5. The correct sensor reading should be under the Measure label.
Continuing reading the temperature DAT3012

Digital input and Counter DAT3012 Modbus Slave.

  1. Connect 24Vdc to the Input terminals 18 and 19.
  2. Click Continue read.
  3. The channel 0 box under the Digital Input should change state to red.
  4. Remove the 24 Vdc and the box should return to gray.
  5. The counter increases by 1 each time the connection is made.
  6. The counter can be reset when the reset all counters is clicked.
  7. Should a function generator be connected and set to a particular frequency this can be seen under the frequency box.
Digital input on Modbus Slave DAT3012

Providing a 4-20 mA output from the DAT3012 Modbus IO Module.

  1. Under the measure label type 20 for 20 mA output.
  2. Click write.
  3. On Terminal D and E you should be able to read 20 mA with a multimeter.
  4. On terminal G and E you will be able to measure 20mA if you connect in series a 24 Vdc power supply.
  5. Type 4mA to measure 4 mA on the output.
  6. Type in any other number between 0 and 20mA and to check the entire mA output range. ted and set to a particular frequency this can be seen under the frequency box.
Analog output on Modbus RTU DAT3012

Checking the relay output operation of the DAT3012 Modbus RTU Analog and Digital IO Slave module.

  1. Measure the resistance across relay output terminals K and L. It should be open circuit.
  2. Click the 0 tab inside the box next to the Digital Output label.
  3. You should be able to hear the relay operation and measure the low resistance across the Modbus relay output Slave terminals K and L, relay out 0.f
Relay output on Modbus RTU DAT3012
The actual Address of the DAT3012 connected.
The actual baud rate of the DAT3012 connected.
The actual parity mode of the DAT3012 connected.
The actual number of bit selection of the DAT3012 connected.
The actual Modbus modality (RTU or ASCII) set for the DAT3012 connected
The string read from the DAT3012 of 4 ASCII characters used to name it example DAT3012.
The firmware version read from the DAT3012.
The watchdog time read from the DAT3012 is in steps of 0.5 seconds.
The delay time between the reception of a query and transmission of the response. Expressed as steps of 1 millisecond.
Indicates if the bit to enable the watchdog time of the device has been set: red indicates the bit is set, grey indicates the bit is not set.
Indicates if the watchdog timer event is occurred: red if the event occurs, grey if the event has not occurred. This condition is also signaled by the blinking of the led “PWR” of the device and the safe state of the digital outputs.
Indicates if the Power up event has occurred: red if the event has occurred, grey if the event has not occurred. This condition is also signaled by the power-up state of the digital outputs.

Frequently Asked Questions about DAT3012

What is the DAT3012?
The DAT3012 is a Modbus RTU I/O module with 2 universal analog inputs, 2 analog outputs, 4 digital inputs, and 3 relay outputs, designed for flexible signal acquisition and control.
What types of analog inputs does it support?
The DAT3012 supports voltage, thermocouples, RTDs, resistance, potentiometers, and current inputs. Input type can be selected remotely via Modbus.
How many digital inputs does it have?
It provides 4 digital inputs, each capable of operating up to 3 kHz, making them suitable for counters or fast pulse detection.
What relay outputs are included?
The module has 3 SPST relay outputs rated up to 2 A, which can be used for alarms, control signals, or switching external circuits.
What analog outputs are available?
It provides 2 isolated analog outputs configurable as 4–20 mA or 0–20 mA.
Does the DAT3012 provide isolation?
Yes. It features full galvanic isolation between inputs, outputs, power supply, and RS-485 communication.
How does it communicate?
The DAT3012 communicates as a Modbus RTU slave over an RS-485 network.