Modbus Relay Modules

Prodigy RTU/TCP Modbus Relay Modules With Analog and Digital Inputs (DIN Rail Compatible)

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Introduction

Numato Lab’s ZRX16/32/64 Channel DIN Rail compatible Modbus RTU/TCP Relay Module with Digital IO and Analog Inputs offers great flexibility at lower cost.  Ease of use and wider operating system compatibility are the primary goals behind this product’s design. Built in USB to serial conversion allows the module to be used without any USB specific knowledge. Industry standard Modbus protocol support allows this product to be used with most automation software that supports Modbus. For power users, this module can be controlled by writing programs in various programming languages of their choice.

Features:

  • Industry standard Modbus protocol support
  • DIN Rail compatible
  • 16/32/64 Mechanical Relay with contact rating up to 250V/5A each
  • 8 TTL (3.3V) compatible Digital IOs
  • 8/6 analog inputs with 12-bit resolution (multiplexed with Digital IOs)
  • USB interface with CDC support. As easy as using a serial port, no USB knowledge required
  • Fully isolated design with opto-couplers and built in DC – DC converter
  • Relay contacts available on easy to access screw terminals
  • 12V external power supply (included)
  • Can be controlled by using industry standard automation applications or custom applications

Some of the possible uses of this module include

  • Home Automation
  • Lighting Control
  • Garden Equipment Control
  • Industrial Automation
  • Test Fixtures
  • DIY and Hobby

This product is compatible with the following operating systems:

  • Windows XP and later versions (Windows 7, 8/8.1, 10 and future versions)
  • Windows 7 Embedded and later
  • Linux
  • Mac OS X
  • Android
  • Or any other operating system that supports USB CDC devices.

And these are some of the languages that can be used for programming:

  • C/C++
  • Visual Basic (VB6, VB2008, VB2010 express and other editions)
  • Visual Basic for Applications (Microsoft Office VBA)
  • Perl
  • Python
  • JAVA
  • Android
  • JavaScript (Node.js)
  • LabVIEW
  • And many more…

This product has 16/32/64 on board relays and associated drivers capable of controlling variety of devices including lamps, motors, locks etc… (Please see recommendations for using this product with inductive loads elsewhere in this document). This module also includes General Purpose I/Os, and analog inputs (multiplexed with GPIOs) that can be accessed over USB interface for extended functionality. The module communicates with host PC over full speed USB link, RS485 and Ethernet interface. When connected to PC using USB/RS485, the module will appear as a serial port in Windows Device Manager (or a serial tty device in Linux and Mac).

How to Use Prodigy Relay Modules

Using this product is very easy,  thanks to support for industry standard Modbus protocol, the RTU and the TCP/IP Network interface that allows the device to be used with most readily available Data Communication Test Software like QModMaster.  This document has more information about using this device with the following software. But in no way limited to this software though.

  • Windows
    • QModMaster
    • Radzio! Modbus Master Simulator
  • Linux
    • Coming soon
  • Mac OS X

    • Coming soon

Using this product with RTU involves the following simple steps.

  1. Connect the device using a USB A to B cable or a USB to RS485 converter to the host system
  2. Install driver if applicable
  3. Open the COM port corresponding to the device using a software that supports Modbus
  4. Read/Write Coils and Registers
  5. Optionally write a script or custom application to automate your task

Using this product with TCP/IP Network interface involves the following steps.

  1. Connect the device using a CAT 5e Ethernet Cable(Straight through cable) to the host system
  2. Connect to the IP corresponding to the device using a software that supports Modbus TCP
  3. Read/Write Coils and Registers
  4. Optionally write a script or custom application to automate your task

All aspects of the above steps are covered in the following sections including step by step demonstration.

Components/Tools Required

Along with your Prodigy ZRXxx device, you will need the items in the list below for easy and fast installation.
1. USB A to B cable (Included)For USB Interface.
2. CAT 5e Ethernet Cable(Straight through cable)For Ethernet Interface.
3. USB to RS-485 ConverterFor RS485 Interface.
4. 12V Power Supply (Included).
5. Medium size Philips screw driver.

Connection Details

IMPORTANT! Please exercise utmost caution while working with electrical mains or other high voltages. Failure to comply with safety regulations may result in injury and or death.

The picture above shows basic connection diagram that can be used in most of the situations. The connection diagram is same for both AC and DC loads. Please make sure to use a freewheeling diode or snubber circuit if the load is inductive. More details about using inductive loads is available elsewhere in this document. Use a USB A to B cable to connect the unit to a PC. It is important to make sure that the wires used to connect loads are sufficiently rated to handle expected load current. Exercise caution while working with high voltages. Short circuits can cause damage to the module and the PC. The following sections identify individual connections in detail.

USB Interface

The on board full speed USB controller helps a PC/Linux/computer to communicate and control this module seamlessly. Use a USB A to B cable (Included) to connect the unit to a PC. The device can be connected directly to the host PC or connected through a compatible USB hub. For high-performance system integration, it is recommended to connect the device directly to one of the root ports.

RS485 Interface

A USB to RS485 converter helps a PC/Linux/computer to communicate and control this module seamlessly. Use a USB to RS485 converter to connect the unit to a PC. The device can be connected directly to the host PC or connected through a compatible USB hub. For high-performance system integration, it is recommended to connect the device directly to one of the root ports.

Ethernet Interface

32 Channel Ethernet GPIO Module Ethernet PortThe on-board Ethernet port supports Ethernet 10 Mbps transmission speed that helps a computer to communicate and control this module easily. There are two basic network configurations for this board/can be used in two ways.

 

  1. Direct connection to Local Area Network(LAN) via common straight through Ethernet cable.
    Eg: Connecting the module to a switch in a network.
  2. Direct connection to a PC through a cross over Ethernet cable. Eg: Connecting the module directly to the PC. Some PC/Laptops can detect and adapt to the cable type. In such situations, a straight through cable also can be used.

Relay Contacts

Prodigy ZRX devices has 16/32/64 mechanical relays that can switch up to 5A of current. IN and OUT connections to the relays are available externally on screw terminals for easy user access. The relays are rated for AC and DC supply voltages. Please see the electrical parameter table for more details. Each relay has two contacts(IN, OUT. The contacts IN and OUT will be connected when the relay is turned ON and will be disconnected when relay is turned OFF.  Table below summarizes possible relay contact positions.

Relay State Connection between IN and OUT
OFFOpen
ON Close

GPIO/Analog Inputs

In addition to the onboard relays, this Prodigy ZRX device has 8/6 General Purpose IO pins that can be used for various custom applications. Some of these or all of these pins depending on the device can be used as Analog to Digital Converter inputs as well. All IO pins support 3.3V TTL signals and the ADC input range is 0 to +3.3V. The ADC can acquire analog signal at the resolution of 12 bits per sample. It is recommended to use a series resistor with the GPIO/ADC pins when interfacing with other circuits. In output mode, GPIOs can source up to 20mA. So no additional circuitry is needed to drive regular LEDs. A 470 Ohms series resistor is recommended for current limiting when connecting LED to a GPIO.

In contrast to GPIOs, Analog inputs can read voltages at any level between 0 to 3.3V. It is recommended to use a series resistor to protect the input from stray voltages and spikes. The internal Analog to Digital converter supports 12 bits resolution which is adequate for most applications. The table below summarizes the GPIO and Analog to Digital Converter input positions of ZRX16/32/64 on the screw terminals.

GPIOZRX16/32ZRX64
IO0ADC0ADC0
IO1ADC1ADC1
IO2ADC2ADC2
IO3ADC3ADC3
IO4ADC4ADC4
IO5ADC5ADC5
IO6ADC6-
IO7ADC7-
GNDGNDGND

 

DC Power Supply

This product requires an external 12V power supply to function. The power supply unit required is included with the product. Connect the power supply to the connector on the product marked as +12V power. This product uses a single power supply for the digital circuitry and the relay coils. An internal isolated DC-DC converter and a set of opto-couplers ensure galvanic isolation between the digital circuitry and the relay coil driver circuitry.

Driver Installation

Installing Numato Lab CDC Driver - Windows Desktop and Server Editions

The driver package for Numato Lab’s Prodigy models can be downloaded from the product page at https://numato.com. To install the driver, unzip the contents of the downloaded driver package to a folder. Attach USB cable to the PC and when asked by Windows device installation wizard, point to the folder where driver files are present. When driver installation is complete, the module should appear in Windows Device Manager as a serial port. The picture below shows a Prodigy ZRX64 visible in Windows Device Manager. For other ZRX devices, the name will be different but how the device is displayed and used is exactly same.
Device Manager

Note down the name of the serial port (COM1, COM2 etc..). This information is required to control the module from the PC.

You may notice that the driver package does not come with a .sys or .exe file as most driver packages do and is expected to be that way. The driver binary necessary in this case is shipped with all copies of windows Desktop/Server editions and gets installed automatically while Windows is installed for the first time. The .inf and .cat files present in the driver package downloaded from http://numato.com merely associate this pre-existing driver with the attached Numato Lab device .

The following video demonstrates how to install the driver on Windows 10.

Installing on Windows Embedded Editions

Windows Embedded editions do not install the infrastructure necessary for USB CDC by default in favor of a smaller footprint. This will cause the driver install to fail unless the necessary files are manually installed prior to installing the driver. Please follow the steps below to install the prerequisites and driver correctly. These steps are tested on Windows 7 Embedded Edition. The installation procedure may vary for other versions of Windows Embedded. Please contact Microsoft for more information.

  1. Locate winemb-inf-mdmcpq.cab on Win 7 Embedded DVD/ISO image
  2. Copy winemb-inf-mdmcpq.cab to a folder Ex: C:Temp
  3. Run command DISM.exe /online /Add-Package /PackagePath:C:Temp
  4. Wait for Windows to restart (Restart machine manually if DISM does not restart the machine automatically)
  5. After reboot is complete, plug the device to a USB port and install driver normally (Driver is available for download at the product page)
For more information or for additional help on Windows Embedded editions, please contact Microsoft or your Windows Embedded reseller

Installing on Linux

To use any device that uses USB CDC protocol with Linux, USB CDC driver needs to be compiled in to the kernel. Fortunately, most Linux distributions (Ubuntu, Redhat, Debian etc..) has this driver pre-installed. The chances of you requiring to rebuild the kernel to include the USB CDC driver is very slim. When connected to a Linux machine, this product should appear as a serial port under /dev directory. Usually the name of the device will be ttyACMx or similar. The name may be different depending on the Linux distribution you have. The image below shows the result of ls /dev command on a Linux Mint system with a USB GPIO/Relay device attached.

Device Listing on Linux

In this particular case, the device shows up as ttyACM0 (highlighted in orange color) but it could be ttyACM1 or ttyACM2  etc… depending on the specific system and other connected devices. Once the device is visible under /dev directory, it can be treated just like any other serial device. Commands can be sent to the device using any mechanism that is valid for regular serial ports such as screen command or Serial Terminal Emulation applications. If there are more than one devices connected to the same host computer, each device will be displayed as separate serial devices with unique names. These separate serial devices can be used to control individual devices attached.

Installing on Mac OSX

Mac OSX is usually shipped with USB CDC driver pre-installed. When connected to a Mac computer, this product should appear as a serial port under /dev directory. Usually the name of the device will be tty.usbserialportx or tty.usbmodemx or similar. The name may be different depending on the Mac OSX version you have. The image below shows the result of ls /dev/*usb* command on a Mac OSX Yosemite system with a USB GPIO/Relay device attached.Listing USB GPIO Devices on Mac OSX

In this particular case, the device shows up as tty.usbmodem141141 (highlighted on orange color) but it could be any name starting tty.usbmodem  or even a completely different name depending on the exact version of operating system and other connected devices. Once the device is visible under /dev directory, it can be treated just like any other serial device. If there are more than one devices connected to the same host computer, each device will be displayed as separate serial devices with unique names. These separate serial devices can be used to control individual devices attached.

The Modbus Interface

Prodigy ZRX series Modbus Relay Modules use Modbus protocol for it’s primary interface. Modbus is a simple yet powerful industry standard protocol that was originally developed by Modicon systems for transmitting/receiving information over serial links. Prodigy devices use USB/RS485 and TCP/IP as the physical interfaces. Since the device use USB interface, it represents itself to the operating system as classic serial device which makes Modbus a very suitable protocol for this product. This also completely hides the complexities of using USB protocol and thus making Prodigy devices as easy to use as a normal serial device.

When working with Modbus, there are two important aspects of the protocol that the user may need to understand. 1) How to send and receive Modbus packets 2) The Modbus Register Map. One need to learn details of building, sending and receiving Modbus packets only if he/she is engaged in low level library or application development (and thus not covered in this document). For an end user who wish to use Prodigy devices with an off the shelf software, understanding of Modbus register map would be sufficient.

Modbus Register Map

Coils

Coils are single bit data type that represents the output state of a single bit entity such as Relay or a GPO. Please note that Coils are always used to represent and output quantity. Writing to a coil will update the output quantity with the value written. Reading a coil will return the data that was previously written. For example, writing “1” to a coil that represents a relay will turn ON the relay and vice versa. Reading from a Coils that represents a turned OFF relay will return value “0”. The Address in the table below shows the position of each coil within the Modbus register map. There are 8 coils corresponding to the 8 GPOs and another set of 16/32/64 coils corresponding to the Relays on ZRX16/ZRX32/ZRX64. The data address of the Coils can be used to access the corresponding Relay or GPO.

No.NameCoil NumberData AddressSizeComments
ZRXxx GPOs
1GPO0101GPO0 ON/OFF
2GPO1211GPO1 ON/OFF
3GPO2321GPO2 ON/OFF
4GPO3431GPO3 ON/OFF
5GPO4541GPO4 ON/OFF
6GPO5651GPO5 ON/OFF
7GPO6761GPO6 ON/OFF
8GPO7871GPO7 ON/OFF
ZRXxx Relays
9Relay065641Relay0 ON/OFF
10Relay166651Relay1 ON/OFF
11Relay267661Relay2 ON/OFF
------
------
22Relay1378771Relay13 ON/OFF
23Relay1479781Relay14 ON/OFF
24Relay1580791Relay15 ON/OFF
ZRX32/64 Relays Continued
25Relay1681801Relay16 ON/OFF
26Relay1782811Relay17 ON/OFF
27Relay1883821Relay18/ ON/OFF
----- -
------
38Relay2994931Relay29 ON/OFF
39Relay3095941Relay30 ON/OFF
40Relay3196951Relay31 ON/OFF
ZRX64 Relays Continued
41Relay3297961Relay32 ON/OFF
42Relay3398971Relay33 ON/OFF
43Relay3499981Relay34 ON/OFF
------
------
------
68Relay601251241Relay60 ON/OFF
69Relay611261251Relay61 ON/OFF
70Relay621271261Relay62 ON/OFF
71Relay631281271Relay63 ON/OFF

Discrete Inputs

Discrete Inputs are single bit data type that represents the input state of a single bit entity such as a GPI. For example, by reading the Input bit corresponding to a GPI, the user can get the state of the logic (HIGH/LOW) externally applied to the GPI.

No.NameInput NumberData AddressSizeComments
GPIs
1GPI01000101GPI0 Status High/Low
2GPI11000211GPI1 Status High/Low
3GPI21000321GPI2 Status High/Low
4GPI31000431GPI3 Status High/Low
5GPI41000541GPI4 Status High/Low
6GPI51000651GPI5 Status High/Low
7GPI61000761GPI6 Status High/Low
8GPI71000871GPI7 Status High/Low

Holding Registers

No.NameInput NumberData AddressSize                AccessComments
Relay Related Registers
1Relay Timer Registers 40001048 for ZRX16
96 for ZRX32
192 for ZRX64
WR3*16=48 Relay timer registers for 16 relays
3*32 = 96 Relay timer registers for 32 relays
3*64 = 192 Relay timer registers for 64 relays
2Relay Fail safe Value Registers402572561 for ZRX16
2 for ZRX32
4 for ZRX64
WRFail Safe value registers for relays.
3Relay Power ON value Register402612601 for ZRX16
2 for ZRX32
4 for ZRX64
WRPower ON value registers for relays.
GPIO Related Registers
4GPIO Timer Registers4026526424WR3*8= 24 GPIO timer registers for 8 GPIOs
5GPO Pullup Value Registers405215201WRPull-up Value register for GPOs
6GPO Pull down Value Registers405255241WRPull-down value register for GPOs
7GPO Open drain Value Registers405295281WROpen drain value register for GPOs
8GPO Fail Safe Value Registers405335321WRFail safe Value register for GPOs
9GPO Power ON Value Registers405415401WRPower ON value register for GPOs
Watchdog Configuration Area
10Watchdog Holding Registers406136123WRWatchdog Config, timer, timeout value registers
Device Configuration Area
11User ID4805180502WRTwo registers (4 bytes) for storing custom user data.
12USB Configuration Area4810181003WRSlave ID, Baud rate, protocol config value registers for USB Interface
13RS485 Configuration Area4816581642WRSlave ID, Baud rate value registers for RS485 Interface
14Ethernet Configuration Area48229822823WR & ROHost name, IP address, MAC etc... for Ethernet Interface

Input Registers

No.NameInput NumberData AddressSize                
AccessComments
Device Info Area
1Vendor ID3800180001 RO
2Product ID3800280011RO
3OEM Vendor ID3800380021RO
4OEM Product ID3800480031RO
5HW major version and Minor version3800580041ROHardware revision information.
6Firmware major, minor version3800680051ROFirmware revision information
7Register Map major, minor version3800980081ROMajor and Minor versions for Modbus register map
★ RO – Read Only ★ WO – Write Only ★ WR – Write/Read

Register Formats

Let’s look how to write values to each registers.

Holding registers and it’s format are explained in the table below :-

No.RegisterRegister FormatComments
Relay Timer Registers
1Relay Timer Value Registers- 2*16 bit Registers for 32 bit timer value for relays.Register 1 - Lower Bytes of Timer value.
Default Value - 0
Minimum Value to be written - 500h
Register 2 - Higher Bytes of Timer Value.
Default Value - 0
2Relay Timer Config Register- 16 bit register

- Bit 0 - Enable Timer

- Bit 1:2 - Timer Type

- Bit 3:4 - Timer Action
Bit 0 :-
0 - Stops Timer
1 - Starts Timer
Default Value - 0
------------------------
Bit 1:2 :-
00 - Single shot Timer
01 - Periodic Timer
Default Value - 0
------------------------
Bit3:4 :-
00 - Relay OFF
01 - Relay ON
10 - Relay Toggle
11 - Reserved
Default Value - 0
3Relay Fail Safe Value Register- 16 bit register for 16 Relays.
- Each bit for each relay
Each bit represents relay status.
0 - Relay OFF
1 - Relay ON
Default Value - 0
4Relay Power ON Value Register- 16 bit register for 16 relays
- Each bit for each relay
Each bit represents relay status.
0 - Relay OFF
1 - Relay ON
Default Value - 0
GPIO Timer Registers
5GPIO Timer Value Registers- 2*16 bit Registers for 32 bit timer value for GPIOs.Register 1 - Lower Bytes of Timer value.
Default Value - 0
Minimum Value to be written - 10h
Register 2 - Higher Bytes of Timer Value.
Default Value - 0
6GPIO Timer Config Register- 16 bit register

- Bit 0 - Enable Timer

- Bit 1:2 - Timer Type

- Bit 3:4 - Timer Action
Bit 0 :-
0 - Stops Timer
1 - Starts Timer
Default Value - 0
------------------------
Bit 1:2 :-
00 - Single shot Timer
01 - Periodic Timer
Default Value - 0
------------------------
Bit3:4 :-
00 - GPIO OFF
01 - GPIO ON
10 - GPIO Toggle
11 - Reserved
Default Value - 0
7GPO Pull-Up Value Registers- 16 bit Register for 16 GPOs
- Each bit for each GPO
Each bit to enable/Disable pull-up for the GPOs.
0 - Pull-Up Disabled
1 - Pull- Up Enabled
Default Value - 0
8GPO Pull-down Value Registers- 16 bit Register for 16 GPOs
- Each bit for each GPO
Each bit to enable/Disable pull-down for the GPOs.
0 - Pull-Down Disabled
1 - Pull- Down Enabled
Default Value - 0
9GPO Open Drain Value Register- 16 bit Register for 16 GPOs
- Each bit for each GPO
Each bit to enable/Disable open drain for the GPOs.
0 - Open drain Disabled
1 - Open drain Enabled
Default Value - 0
10GPO Fail Safe Value Registers- 16 bit Register for 8 GPOs
- Bit 0:7 - Each bit for each GPO
- Bit 8:15 - Each bit for Input/Output mode of GPOs
Bit 0:7 :-
Each bit represents GPO status.
0 - GPO OFF
1 - GPO ON
Default Value - 0
------------------------
Bit 8:15 :-
Each bit represents the Input/Output mode of corresponding GPOs
0 - Output
1 - Input
Default Value - 0
11GPO Power ON Value Registers- 16 bit Register for 8 GPOs
- Bit 0:7 - Each bit for each GPO
- Bit 8:15 - Each bit for Input/Output mode of GPOs
Bit 0:7 :-
Each bit represents GPO status.
0 - GPO OFF
1 - GPO ON
Default Value - 0
------------------------
Bit 8:15 :-
Each bit represents the Input/Output mode of corresponding GPOs
0 - Output
1 - Input
Default Value - 0
Watchdog Holding Registers
12Watchdog config Register -16 bit register to Enable/Disable watchdog timer
- Bit 0 - ON Bit
- Bit 1 - Mode Select Bit
- Bit 2:15 - Reserved
Bit 0 :-
0 - Disable Watchdog Timer
1 - Enable Watchdog Timer
Default Value - 0
------------------------
Bit 1 :-
0 - Default Mode
1 - Manual Mode(Reserved)
Default Value - 0
------------------------
Bit 2:15 :-
XX - Reserved
Default Value - 0
13Watchdog timer Value Register - 16 bit Register for watchdog timer value.Fail safe occurs when this value reaches the timeout value.
Default Value - 0
14Watchdog timeout Value - 16 bit Register for watchdog timeout value. Represents at what time the fail safe should occur.
Default Value - 0
Common Configuration Holding Registers
15User ID Holding Register- 2*16 bit registers for User ID
4 bytes for User ID.
Default Value - 0
USB Configuration Holding Registers
16Slave ID- 16 bit register for USB Slave IDDefault Value - 1
17Baud Rate- 16 bit register for USB baud rateBaud rate can be 9600, 19200, 38400, 57600, 115200
Default Value - 57600
18Protocol Configuration- 16 bit register for swap between protocols(RTU,JSON,XML)
- Bit 0:2 - Config Bit
Bit 0 :-
0 - Disable RTU
1 - Enable RTU
Default Value - 1
------------------------
Bit 1 :-
0 - Disable JSON
1 - Enable JSON
Default Value - 0
------------------------
Bit 2 :-
0 - Disable XML
1 - Enable XML
Default Value - 0
RS485 Configuration Holding Registers
19Slave ID- 16 bit register for RS485 Slave IDDefault Value - 1
20Baud Rate- 16 bit register for RS485 baud rateBaud rates - Values
----------- ---------
9600 - 10 or 0x000A
19200 - 11 or 0x000B
38400 - 12 or 0x000C
57600 - 13 or 0x000D
115200 - 14 or 0x000E
Default Value - 10 or 0x000A
Ethernet Configuration Holding Registers
21Host Name- 8*16 bit registers for host nameHost name length is limited to 16 characters
22IP address- 2*16 bit registers for IP AddressIP V4 properties of Ethernet interface.
23IP Mask- 2*16 bit registers for IP Mask
24Default Gateway- 2*16 bit registers for Default Gateway
25Primary DNS- 2*16 bit registers for Primary DNS
26Secondary DNS- 2*16 bit registers for Secondary DNS
27DHCP Enable-16 bit register for DHCP
Enable
- Bit 0 - Enable Bit
- If enabled, Get IP address automatically, or static IP configuration.
- Disable DHCP to write IPV4 properties.
Bit 0 :-
0 - Disable DHCP
1 - Enable DHCP
Default Value - 1
------------------------
Bit 1:15 :-
X -Reserved
Default Value - 0
28TCP Port- 16 bit registers for TCP PortTCP port for Ethernet connection.
Default value - 502
29MAC Address- 3*16 bit Read Only registers for MAC AddressMAC address of Ethernet interface

★ IP V4 properties of Ethernet interface will be writable only if the DHCP is disabled.

Similarly, input registers’ format are as follows :-

No.RegisterRegister FormatComments
1Vendor ID- 16 bit Register for Vendor IDDefault Value - 0x2A19
2Product ID- 16 bit Register for Product IDZRX64 - 0x2504 or 0x2501
ZRX32 - 0x2505 or 0x2502
ZRX16 - 0x2506 or 0x2503
Default Value - Depends on the Product
3OEM Vendor ID- 16 bit register for OEM Vendor IDDefault Value - 0
4OEM Product ID- 16 bit register for OEM Product IDDefault Value - 0
5HW major version and Minor version- 16 bit register for Hardware major and minor versionHardware revision information.
Default Value - 1
6Firmware major, minor version- 16 bit register for Firmware major and minor versionFirmware revision information.
Default Value - 1
7Firmware bugfix/patch level- 16 bit register for Firmware bugfix/patch levelFirmware bugfix/patch level
Default Value - 0
8PNV data format major, minor version- 16 bit register for PNV data format major, minor versionPNV data format major, minor version
Default Value - 1
9Register Map major, minor version- 16 bit register for Register map major and minor versionMajor and Minor versions for Modbus register map
Default Value - 1

Controlling Prodigy ZRXxx using off the shelf software

Prodigy ZRX devices’ support for Modbus protocol makes it easier to use with virtually any software that supports Modbus. This section of the document demonstrates how to use Prodigy ZRX devices with some of the software that are available in the market.

Windows

qModMaster

QModMaster is a free software that emulate Modbus master and can be used to access any device that is Modbus compatible. QModMaster can be downloaded for free at at https://sourceforge.net/projects/qmodmaster/. Follow the steps below to see how to use Prodigy ZGX/EG devices with QModMaster using RTU and TCP.

Download and install QModMaster.

To control the device via Modbus RTU, follow the simple steps given below:

Step 1:

Run QModMaster and select “Modbus RTU” from Options menu. Enter Serial Port name and other settings as in the image below and click OK. Serial Port name must match the port name assigned to the device by the Operating System.
qModMaster Settings for ZRXxx

Step 2:

  1. Select RTU as Modbus mode.
  2. Select proper Slave ID of the device.
  3. Then, click the “Connect” button to connect to the device.

qModMaster Open Port

Step 3:

  1. Select “Write Single Coil” function code in the Function Code combo box, enter the Data Address of the first Relay (Relay Index 0) in the Start Address box.
  2. Enter value 1 (corresponds to Relay ON state) in the data cell.
  3. Now click the Read/Write button to send the new value to the device.

If everything works fine, you will hear the relay clicks and any circuitry connected to the relay will be activated. To read the status of a Relay, the same sequence apply but select the “Read Coils” function code instead.

qModMaster Turn Relay ON

Similarly, to control the device via Modbus TCP, follow the steps below:

Step 1:

Run QModMaster and select “Modbus TCP” from Options menu. Enter IP Address of the device and TCP port number as in the image below and click OK.
qModMaster TCP Settings for ZGXxx
Step 2:

  1. Select TCP as Modbus mode.
  2. Then, click the “Connect” button to connect to the device.

qModMaster TCP Open Connection
Step 3:

  1. Select “Write Single Coil” function code in the Function Code combo box, enter the Data Address of the first Relay (Relay Index 0) in the Start Address box.
  2. Enter value 1 (corresponds to Relay ON state) in the data cell.
  3. Now click the Read/Write button to send the new value to the device.

If everything works fine, you will hear the relay clicks and any circuitry connected to the relay will be activated. To read the status of a Relay, the same sequence apply but select the “Read Coils” function code instead.

qModMaster Turn Relay ON

Additional Information

Using relay modules with inductive loads

Snubber Diode

Diode As Snubber

It is important to take additional care when using relays with inductive loads. An inductive load can be pretty much anything that has a coil and works based on magnetic principles like Motors, Solenoids and transformers. But in practice, even a wire longer than a few feet can display substantial inductance. Inductive loads produce back emf when the magnitude of the load current changes. The back emf can be in the order of tens or even hundreds of voltage (See this Wikipedia article http://en.wikipedia.org/wiki/Counter-electromotive_force). This effect is most severe when power is disconnected from inductive load because the rate of change of current is maximum at that point. Even though the back emf lives only for a very short time (a few milliseconds) it can cause sparks between the relay contacts and can deteriorate the contact quality over time and reduce the life span for the relays considerably.

So it is important to take countermeasures to suppress the back emf to acceptable levels to protect relay contacts. Usually this requires connecting electronic devices in parallel with the load such that they absorb the high voltage components generated by the load. For solenoids, connecting a diode (fast switching diode is recommended) in parallel to the load (in reverse direction to the load current) is very effective. A diode used for this purpose is usually called a freewheeling diode. Please see the diagram on the right for connection details.

Capacitive Snubber

Capacitor As Snubber

A capacitor with proper rating is recommended for protecting the relay contacts when a motor is used as load. The capacitor should be rated enough to withstand the back emf that is generated by the motor. Please see the diagram below for connection details.

Please note that the relay modules are NOT shipped with back emf suppression devices pre-installed. The exact kind of suppression device and the parameters of the selected device can vary depending on the load itself. Some of the parameters that affects the suppression device selection are the inductance of the load, power supply voltage, load current, physical size/structure of the load etc.. It is obvious that it is impossible for us to predict these parameters and design required back emf suppression device and incorporate that on the board. So we believe this is a task best left to the module user. There is an excellent article on designing back emf suppression on Wikipedia at http://en.wikipedia.org/wiki/Flyback_diode

Analog to Digital Converters (ADCs)

Prodigy UR devices do support Analog to Digital Conversion on some of the GPIO terminals. A list of GPIOs that supports analog function in this product is listed elsewhere in this document. GPIOs doesn’t need to be configured specially in order to use them as analog inputs. Simply reading the Analog Input Register corresponding to the IO will automatically put the IO in to Analog Input mode and read the analog value . Resolution of the ADC on this product is 12 bits. The input voltage range of the ADC is 0 – 3.3V.

GPIO with Switches

USBGpio Switch connection diagramIt is possible to read the position of a switch that is connected to a GPIO. A SPST or SPDT switch is recommended to use with GPIOs. Push switches that maintain the contacts closed only for a very short time so using them is discouraged. The fundamental idea of using a switch with GPIO is to have the switch cause a voltage level change at the GPIO pin when pressed. Usually this is achieved by using an external pull-up resistor along with the switch. The pull up resistor is connected between the GPIO and VDD and the switch is connected between the GPIO and ground. When the switch is not pressed, the pull-up resistor will cause the GPIO to stay at VDD voltage level. When the switch is pressed, the GPIO is short circuited to ground and stays at zero voltage. This change in voltage and thus the position of the switch can be read by simply reading the Discrete Input bit corresponding to the GPIO.

Technical Specifications

ParameterValueUnit
Number of relays 16/32/64
Number of GPIOs8
Number of analog inputs (Multiplexed with GPIOs)8/8/6
Power supply voltage (External)12V
IO Specifications
Maximum IO source current20mA
Maximum IO sink current20mA
GPIO input low voltage 0.8V
GPIO input high voltage 2V
GPIO output low voltage 0V
GPIO output high voltage 3.3V
ADC Specifications
Resolution12bits
Full scale range0 – 3.3V
Reference voltage2.5V
Recommended Impedance of Analog Voltage Source2.5KΩ
Relay Specifications
Nominal relay coil voltage 12V
Nominal coil power consumption (per relay)120mW
Relay contact material Silver Alloy
Contact rating 5A/ 250V AC
5A/ 30V DC
Maximum switching voltage 245VAC/ 30VDC
Maximum switching current5A
Maximum switching power1250VA/ 150W
Contact resistance (initial)100mΩ
Insulation resistance1000MΩ
Life expectancy (Electrical) 50,000 Operations
(5A 250VAC/24VDC, Resistive load)
Life expectancy (Mechanical) 20000000Operations
Maximum switching on response time10mS
Maximum switching off response time5mS
Shock resistance (Functional)98m/s2
Shock resistance (Destructive)980m/s2
Vibration resistance10Hz to 55Hz 1.5mm DA
Other Information
USB Vendor ID0x2A19
USB Product IDZRX64 - 0x2501 or 0x2504
ZRX32 - 0x2502 or 0x2505
ZRX16 - 0x2503 or 0x2506

Frequently Asked Questions (FAQs)

Q. What are the serial parameters I need to use when communicating with this board?
A. Since this module uses USB as the underlying transport mechanism, most of the serial parameters do not affect the communication. You can leave all parameters to any legal value (Eg: 2400, 4800, 9600 etc… for baud rate) except Flow control. Flow control needs to be set to “None”.

Q. Where do I find driver for this product?
A. Visit http://numato.com and navigate to the product page. There will be a link to download windows driver. Linux does not require driver installation since in most cases they are shipped with the driver pre-installed.

Q. Why there is no .sys or .exe file in the Windows driver package I downloaded?
A. This product uses USB CDC driver binary which is already present on Windows. All Windows versions (with the exception of Embedded Editions) has this driver binary installed by default. The .inf and .cat files present in the zip file helps Windows identify the device properly and associate appropriate driver (.sys) to the device

Q. Does this product work with Linux?
A. Yes, this product works with Linux. Please see more details on how to use this product with Linux elsewhere in this document.

Q. Does this product work with Mac OSX?
A. Yes, this product works with Mac OSX. Please see more details on how to use this product with Mac elsewhere in this document.

Q. What are the software that this product work with?
A. This product works with almost any software that has support for standard Modbus. Some examples can be found elsewhere in this document. Different software are written by different developers with different purposes in mind. So you may encounter some software that may not work with this product. But usually alternatives are available in most if not all cases.

Q. I’m using x language for programming. How do I find out if this language can be used to program and control the GPIO module?
A. Find out if the language of interest supports some kind of APIs/Functions/Components for serial communication. If it does, most likely you should be able to use that language with this module. It may also be possible to find libraries such as libModbus that offers high level APIs. Using such libraries can speed up development quite a bit.

Q. I need a customized version of this product, can Numato Lab do the customization for me?
A. Yes, we can definitely do customization but there may be minimum order requirements depending on the level of customization required. Please write to [email protected] for a quote.

Q. Where can I buy this product?
A. All Numato products can be ordered directly from our web store http://www.numato.com. We accept major credit cards and Paypal and ship to almost all countries with a few exceptions. We do have distributors in many countries where you can place your order. Please find the current list of distributors at http://numato.com/distrib.

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