Ismacontrolli Sfar-s-16ro Expansion Module - 16 Relay Outputs User Manual

iSMACONTROLLI SfAR-S-16RO Expansion Module – 16 Relay Outputs

Introduction

Thank you for choosing our product.
This manual will help you with proper handling and operating of the device.
The information included in this manual have been prepared with utmost care by our professionals and serve as a description of the product without incurring any liability for the purposes of commercial law. This information does not discharge you from the liability of your own judgement and verification.
We reserve the right to change product specifications without notice.
Please read the instructions carefully and follow the recommendations concluded therein.

WARNING!
Failure to follow instructions can result in equipment damage or impede the use of the hardware or software.

Revision History

Safety Rules

• Improper wiring of the product can damage it and lead to other hazards. Make sure that the product has been correctly wired before turning the power on.
• Before wiring or removing/mounting the product, make sure to turn the power off. Failure to do so might cause an electric shock.
• Do not touch electrically charged parts such as power terminals. Doing so might cause an electric shock.
• Do not disassemble the product. Doing so might cause an electric shock or faulty operation.
• Use the product only within the operating ranges recommended in the specification (temperature, humidity, voltage, shock, mounting direction, atmosphere, etc.). Failure to  do so might cause a fire or faulty operation.
• Firmly tighten the wires to the terminal. Failure to do so might cause a fire.
• Avoid installing the product in close proximity to high-power electrical devices and cables, inductive loads, and switching devices. Proximity of such objects may cause an
• uncontrolled interference, resulting in an instable operation of the product.
• Proper arrangement of the power and signal cabling affects the operation of the entire control system. Avoid laying the power and signal wiring in parallel cable trays. It can  cause interferences in monitored and control signals.
• It is recommended to power controllers/modules with AC/DC power suppliers. They provide better and more stable insulation for devices compared to AC/AC
• transformer systems, which transmit disturbances and transient phenomena like surges and bursts to devices. They also isolate products from inductive phenomena from  other transformers and loads.
• Power supply systems for the product should be protected by external devices limiting overvoltage and effects of lightning discharges.
• Avoid powering the product and its controlled/monitored devices, especially high power and inductive loads, from a single power source. Powering devices from a single
• power source causes a risk of introducing disturbances from the loads to the control devices.
• If an AC/AC transformer is used to supply control devices, it is strongly recommended to use a maximum 100 VA Class 2 transformer to avoid unwanted inductive effects,  which are dangerous for devices.
• Long monitoring and control lines may cause loops in connection with the shared power supply, causing disturbances in the operation of devices, including external  communication. It is recommended to use galvanic separators.
• To protect signal and communication lines against external electromagnetic interferences, use properly grounded shielded cables and ferrite beads.
• Switching the digital output relays of large (exceeding specification) inductive loads can cause interference pulses to the electronics installed inside the product. Therefore, it  is recommended to use external relays/contactors, etc. to switch such loads. The use of controllers with triac outputs also limits similar overvoltage phenomena.
• Many cases of disturbances and overvoltage in control systems are generated by switched, inductive loads supplied by alternating mains voltage (AC 120/230 V). If they do  not have appropriate built-in noise reduction circuits, it is recommended to use external circuits such as snubbers, varistors, or protection diodes to limit these effects.

Module Features

Purpose and Description of the Module

The SfAR-S-16RO module is an innovative device that provides a simple and cost effective extension of the number of lines of output with high current-carrying capacity. The module has 16 relay outputs.

The module is connected to the RS485 bus with a twisted-pair wire. Communication is via Modbus RTU or Modbus ASCII. The use of 32-bit ARM core processor provides fast processing and quick communication. The baud rate is configurable from 2400 to 115200.

The module is designed for mounting on a DIN rail in accordance with DIN EN 5002.
The module is equipped with a set of LEDs to indicate the status of inputs and outputs, power supply, and communication, which is useful for diagnostic purposes and helping to find errors.

Module configuration is done via USB by using a dedicated computer program. It also allows for changing the parameters using the Modbus protocol or set the Modbus address using the DIP switches under the front panel.

Technical SpecificationInterfaceRS485

Table 2. Technical specification

Dimensions

The appearance and dimensions of the module are shown below. The module is mounted directly to the rail in the DIN industry standard. Power connectors, communication and IOs are at the bottom and top of the module. USB connector configuration and indicators are located on the front of the module.

Figure 1. Dimensions

Communication

Grounding and Shielding

In most cases, I/O modules will be installed in an enclosure along with the other devices, which generate electromagnetic radiation. Relays, contactors, transformers, motor invertors, etc., are examples of such devices. Radiation can induce electrical noise into both power and signal lines, as well as direct radiation into the module. Whether or not the SfAR modules are immune to such effects, the interferences must be suppressed at their source if possible to ensure the proper functioning of the entire system. Appropriate grounding, shielding and other protective steps should be taken at the installation stage to prevent these effects. It is recommended to at least follow the rules below:

• line power cables must be routed with spatial separation from signal and data transmission cables; analog and digital signal cables should also be separated;
• it is recommended to use shielded cables for analog signals, cable shields should not be interrupted by intermediate terminals; the shielding should be earthed directly after the cable enters the cabinet.

It is recommended to install interference suppressors when switching inductive loads (e.g., coils of contactors, relays, solenoid valves). RC snubbers or varactors are suitable for AC voltage and freewheeling diodes for DC voltage loads. The suppressing elements must be connected as close to the coil as possible.

Network Termination

Transmission line effects often present problems for data communication networks. These problems include reflections and signal attenuation.
To eliminate the presence of reflections of signal from the end of the cable, the cable must be terminated at both ends with a resistor across the line adequate to its characteristic impedance. Both ends must be terminated since the propagation is bidirectional. In case of an RS485 twisted pair cable, this termination is typically 120 Ω.

Setting Module Address in RS485 Modbus Network

The following table shows how to set DIP switches to determine the address of the module. The module address is set with the switches in the range of 0 to 127. Addresses from 128 to 255 can be set via RS485 or USB and using dedicated software tool.

Table 3. Setting module address in RS485 Modbus network, using DIP switch

Types of Modbus Functions
There are 4 types of Modbus functions supported by the SfAR modules

Table 4. Types of Modbus functions supported by the module

Communication Settings

The data stored in the module’s memory is given in the 16-bit registers. The access to registers is via Modbus RTU or Modbus ASCII.

Default Settings

The default configuration can be restored with the DIP switch, SW6.

Restoring Default Configuration

To restore the default configuration, follow the steps below:

• Turn the power off;
• Turn the DIP switch SW6 on;
• Turn the power on;
• When power and the communication led are lit, turn the switch SW6 off.

WARNING! After restoring the default configuration, all values stored in the registers are cleared as well.

Configuration Registers

Table 6. Configuration registers

Watchdog

This 16-bit register specifies the time in milliseconds to watchdog reset. If the module does not receive any valid message within this time, all digital and analog outputs will be set to default state.
This feature is useful if there is an interruption in data transmission and for security reasons. Output states must be set to the appropriate state in order to reassure the safety of persons or property.
The default value is 0 milliseconds which means the watchdog function is disabled.

Indicators

Figure 2. Indicators

Table 7. Description of indicators

Connections

Block Diagram

Power Supply Connection

DC Power Connection

Figure 4. DC power connection

AC Power Connection

Figure 5. AC power connection

Communication Bus Connection

Figure 6. Communication bus connection

Connection of Relay Outputs

Connection of Resistive Load

Figure 7. Connection of resistive load

Figure 8. Connection of electrovalve

Quick Connector

The Quick Connector is a unique feature of modules that allows for quickly connecting a group of devices with a flat ribbon cable. Thanks to this solution, it is enough to connect power and RS485 communication to one of the devices in the group, and the others will be powered and communicated with ribbon cable. The Quick Connector is sufficient to connect up to 10 devices next to each other. It is important that the various types of modules in the SfAR-S family can be connected with the ribbon cable.

Figure 9. Quick Connector

DIP Switch

Table 8. Description of switches

Module Registers

Registered Access

Bit Access

Configuration Software

The SfAR Configurator is a software, which is designed to set the communication module registers over Modbus network as well as to read and write the current value of other registers of the module. It is a convenient way to test the system as well as to observe real-time changes in the registers.

Figure 11. PC connection

Communication with the module is done via a USB cable. The module does not require any drivers.
The SfAR Configurator is a universal software, where it is possible to configure all available modules.

Figure 12. The SfAR Configurator

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References

• iSMA CONTROLLI S.p.A.