SLM-RLY-8-ISO

SLM-RLY-8-ISO

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Channels: 8
Discrete Output Type: 6 Relays - FORM A (SPST), 2 Relays - FORM B (SPDT)
Rated Voltage: 6-24 VDC, 6-120 VAC
Register Type: Discrete Output/Coil

Specifications:
Download SLM-RLY-8-ISO Datasheet

Description

• 8-channel relay output module with per-channel isolation.

• Supports 120/240VAC or 24VDC relay switching.

• Designed for industrial control applications requiring independent relay outputs.

• Each relay output is individually isolated, ensuring electrical separation between channels.

• Supports both AC and DC loads, providing flexibility in industrial applications.

• Channels 1 and 5 are FORM C relays, meaning that they have both a normally closed and normally open contact.

• Channels 2, 3, 4, 6, 7, and 8 are FORM A, or normally open, relays.

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Configuration

• No configuration required

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Typical Modbus Register Mapping

Note

The following examples assume that it is the only module connected. Actual mapping may vary depending on the configuration of the system.

Channel	Modbus Register	Relay Form	Access
NC1/NO1	00001	FORM C	Read/Write
NO2	00002	FORM A	Read/Write
NO3	00003	FORM A	Read/Write
NO4	00004	FORM A	Read/Write
NC5/NO5	00005	FORM C	Read/Write
NO6	00006	FORM A	Read/Write
NO7	00007	FORM A	Read/Write
NO8	00008	FORM A	Read/Write

Notes:

• Outputs (OUT1-OUT8) are read/write and correspond to Modbus Coil Registers (00001 - 00008).

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Example Usage

Note

The following examples assume that it is the only module connected. Actual mapping may vary depending on the configuration of the system.

Python

import time
from pyModbusTCP.client import ModbusClient
import struct

client_ip = '192.168.1.255'  # Replace with your device's IP
client = ModbusClient(host=client_ip, port=502, auto_open=True)

while True:
    client.write_single_coil(3, True); # Write 1 to coil address 3 (channel 4)
    time.sleep(1)
    client.write_multiple_coils(0, [True, False, True, False, True, False, True, False]); # Alternate values to coils 0-7
    time.sleep(1)

Note

This is an explanatory section on how to read/write to a module. For a more complete example using Python, visit Python Example.

Arduino

// arduino code here
#include <ArduinoModbus.h> // Include Modbus library

// Assume ModbusRTUClient is already initialized (e.g., ModbusRTUClient.begin(...))
int slaveId = 0x01;       // The ID of the Modbus slave device
int startAddress = 0;     // The starting address of the coils
int numCoils = 8;         // The number of coils to write (0-7)
int coilValues[] = {1, 0, 1, 0, 1, 0, 1, 0}; // Values for coils 0 through 7

void setup() {
    # Setup modbus client
}

void loop() {
    writeMultipleCoilsPattern_BeginWriteEnd();
    delay(1000);
}

void writeMultipleCoilsPattern_BeginWriteEnd() {
  // Start writing multiple coils
  ModbusRTUClient.beginTransmission(slaveId, COILS, startAddress, numCoils);

  // Write the pattern 1, 0, 1, 0, 1, 0, 1, 0 for coils 0-7
  for (int i = 0; i < numCoils; i++) {
    // Write 1 for even coils (0, 2, 4, 6), 0 for odd coils (1, 3, 5, 7)
    ModbusRTUClient.write(coilValues[i]);
  }

  // Send the write request
  ModbusRTUClient.endTransmission();
}

Note

The above code uses the ArduinoModbus library and is not a complete program.

Note

This is an explanatory section on how to read/write to a module. For a more complete example using Arduino, visit Arduino Example.

Codesys

Under Modbus_TCP_Server -> Modbus Server Channel Under Modbus_TCP_Server -> Modbus Server Channel -> I/O Mapping Usage

VAR
    RLY8 AT %QB0 : BYTE;
    RLYCH1 AT QX0.0 : BOOL;
    RLYCH2 AT QX0.1 : BOOL;
    RLYCH3 AT QX0.2 : BOOL;
    RLYCH4 AT QX0.3 : BOOL;
    RLYCH5 AT QX0.4 : BOOL;
    RLYCH6 AT QX0.5 : BOOL;
    RLYCH7 AT QX0.6 : BOOL;
    RLYCH8 AT QX0.7 : BOOL;
END_VAR

Note

This is an explanatory section on how to read/write to a module. For a more complete example using Codesys, visit Codesys Example.

Productivity Suite

Tag

Tag Name	Type
DO1	Boolean
DO2	Boolean
DO3	Boolean
DO4	Boolean
DO5	Boolean
DO6	Boolean
DO7	Boolean
DO8	Boolean

Usage

Note

This is an explanatory section on how to read/write to a module. For a more complete example using Productivity Suite, visit Productivity Suite Example.

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Specifications

Download SLM-RLY-8-ISO Datasheet

Safety Precautions

• Do not add or remove modules while field power is applied.

• Ensure proper grounding and wire connections to prevent electrical hazards.

• Follow all local and national electrical codes.

• Maintain adequate ventilation to prevent overheating.

For more details and technical support, visit Synergy Logic or contact support@synergy-logic.com.