EAPL ST-6M1 Sequential Timer – Complete Technical Specification, Working Principle & Industrial Applications
In this article we are going to discuss the complete technical specification and explanation of EAPL ST-6M1 Sequential Timer device. Welcome to the Insight Control System blog page
INTRODUCTION
- EAPL Sequential Timers are multi-channel control devices designed to operate predefined loads in a sequence, ensuring there is no overlap and maintaining a fixed time delay between each operation.
- These timers are housed in sturdy, compact enclosures made of UL-graded flame-retardant plastic, ensuring safety and durability.
- EAPL Sequential Timers are available in multiple switching output channel configurations, with options for both IP enclosure and non-IP enclosure types. These include:
- Sequential Switching 4 channels without IP enclosure,
- Sequential Switching 6 channels with and without IP enclosure,
- Sequential Switching 10 channels with and without IP enclosure
- Sequential Switching 15 channels with and without IP enclosure.
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| Ordering Information |
- In this article, we will focus specifically on the technical specifications of the ST6-M1 Sequential Switching 6-channel timer without IP enclosure.
- The following technical specification covers key parameters including electrical, basic device, output channel, timing and other essential operational characteristics of the device.
ELECTRICAL SPECIFICATION✅
Rated Supply Voltage: 85V to 270V AC/DC
It means the device can safely operate when the input power supply voltage is anywhere between 85 volts and 270 volts, and it can accept both AC and DC power sources.
Rated Frequency 50 / 60 Hz (±5%)
It means the device is designed to operate with power supply frequencies of 50 Hz or 60 Hz, and it can tolerate a variation of plus or minus 5% from these values.
- For 50 Hz supply = acceptable range is approximately 47.5 Hz to 52.5 Hz
- For 60 Hz supply = acceptable range is approximately 57 Hz to 63 Hz
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| Source Voltage |
Rated Frequency of Operation 1800 ±5% Operations per Hour Max:
It means the device relay can switch ON and OFF up to 1800 times per hour, with an allowable variation of ±5%.
- Rated Frequency of Operation = Maximum recommended switching speed.
- 1800 Operations per Hour = Relay can operate 1800 ON/OFF cycles in one hour.
- ±5% = Acceptable range variation.
- Minimum = 1710 operations/hour
- Maximum = 1890 operations/hour, this is the maximum safe operating limit.
The relay should not switch more than around 1800 times per hour, otherwise relay life and performance may reduce.
Power Consumption AC Approx. 15 VA / 3 W
It means the device consumes different amounts of power depending on whether it is powered by AC or DC supply.
- When using AC supply: The device draws about 15 VA (Volt-Ampere) of power.
- When using DC supply: The device consumes about 3 Watts (W) of actual power.
Insulation Resistance > 100 MΩ @ 500 V DC
It means the insulation inside the device has very high resistance (more than 100 Mega Ohms) when tested using 500 Volts DC.
- Insulation Resistance = Measures how well electrical parts are insulated from each other and from ground.
- >100 MΩ (Mega Ohms) = Very high resistance value, meaning very low leakage current.
- @ 500 V DC = Test is performed by applying 500 Volts DC during insulation testing.
The device has strong electrical insulation, which helps prevent leakage current, short circuits, and improves safety and reliability.
Dielectric Strength:
It indicates the ability of the device insulation to withstand high voltage without electrical breakdown or failure.
1. 2.5 kV AC, 50 Hz for 1 minute (Between current carrying & non-current carrying parts)
- The insulation can withstand 2500 Volts AC for 1 minute between live electrical parts and non-live (metal body or isolated parts) without failure.
2. 1.5 kV AC, 50 Hz for 1 minute (Between contacts & control circuit).
- The insulation between relay contacts (load side) and control electronics can withstand 1500 Volts AC for 1 minute.
3. 750 V AC, 50 Hz for 1 minute (Between non-continuous relay contacts)
- Insulation between separate relay contacts (not electrically connected) can withstand
- 750 Volts AC for 1 minute.
This means the device insulation is strong and safe, and it can handle high voltage stress between internal parts without causing short circuit or insulation failure. This ensures electrical safety and reliability.
Electrical Connection: Screw Type Terminals with Self-Lifting Clamps
It means the device uses screw terminals for wiring, and inside the terminal there is a spring or clamp mechanism that automatically lifts to hold the wire securely when the screw is tightened.
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| Screw Type Terminals with Self-Lifting Clamps |
- Screw Type Terminal: Wire is connected by tightening a screw.
- Self-Lifting Clamp: Helps to easily insert the wire and ensures strong and reliable contact after tightening.
This type of connection improves wiring safety, reduces loose connections, and makes installation easier.
OUTPUT SPECIFICATION✅
Control Output:
6 (RLY0 to RLY5, ‘NO’ relay contacts rated for 10A @ 250V AC / 28V DC resistive)
It means the device has 6 relay output channels, named RLY0 to RLY5, and each relay has a Normally Open (NO) contact with a specific load handling capacity.
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| Control Output |
- 6 Outputs (RLY0 to RLY5) → The timer can control 6 separate loads or devices.
- NO (Normally Open) → The relay contact stays open in normal condition and closes only when the relay is activated.
- 10A at 250V AC → Each relay can switch AC load up to 10 Amps at 250 Volts.
- 10A at 28V DC → Each relay can switch DC load up to 10 Amps at 28 Volts.
- Resistive Load → Rating is applicable for loads like heaters, lamps, or simple resistive devices (not motors or inductive loads).
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| Output Channel |
TIMING SPECIFICATION✅
Variation Due to Frequency Change ±1% Max. ±50mSec
It means the device timing accuracy may slightly change if the supply frequency changes, but only within the specified limits.
- Variation Due to Frequency Change = Change in timing accuracy when supply frequency (50/60 Hz) fluctuates.
- ±1% Max = Maximum timing error allowed is ±1% of the set time.
- ±50 mSec (milliseconds) = Or maximum fixed timing variation is ±50 milliseconds.
If power supply frequency slightly changes, the timer may run slightly faster or slower, but only within ±1% or ±50 milliseconds, which keeps the timing performance reliable.
Variation Due to Temperature Change ±2% Max. ±50mSec
It means the timer accuracy may slightly change due to surrounding temperature changes, but only within the specified limits.
- Variation Due to Temperature Change = Timing may slightly vary when ambient temperature increases or decreases.
- ±2% Max = Maximum timing error allowed is ±2% of the set time.
- ±50 mSec = Or maximum fixed timing variation is ±50 milliseconds.
If the surrounding temperature changes, the timer may run slightly faster or slower, but the change will be limited to ±2% or ±50 milliseconds, ensuring stable timer performance.
Variation Due to Voltage Change ±1% Max. ±50mSec
It means the timer accuracy may slightly change if the supply voltage fluctuates, but only within the specified limits.
- Variation Due to Voltage Change = Timing accuracy change when supply voltage increases or decreases.
- ±1% Max = Maximum allowed timing error is ±1% of the set time.
- ±50 mSec = Or maximum fixed timing variation is ±50 milliseconds.
If the power supply voltage changes slightly, the timer may run slightly fast or slow, but only within ±1% or ±50 milliseconds, so the timer remains reliable.
On time range: 0.1Sec to 99Hrs 59Min for each channel
- For each output channel, you can set how long the output stays ON (energized).
- The adjustable ON duration can be as short as 0.1 second and as long as 99 hours 59 minutes.
- ON time range defines the minimum and maximum adjustable duration for which each timer channel output remains energized during operation.
Off time range: 0.1Sec to 99Hrs 59Min for each channel
- It means how long each channel output can stay OFF.
- You can set the OFF time from 0.1 second up to 99 hours 59 minutes.
- Each channel can have its own OFF time setting.
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| Time Selection |
Accuracy and Performance Specification✅
Setting accuracy: ± 0.1% max. w.r.t Setting ± 50mSec
- Setting accuracy means how close the actual time will be compared to the time you set.
- ±0.1% of setting = Timer error can be only 0.1% of the set time.
- ±50m Sec = There can be maximum extra error of 50 milliseconds.
Repeat accuracy: ± 0.05% max. ± 50mSec
- Repeat accuracy means how same the timing will be every time the timer repeats.
- ±0.05% max. = Timing variation between cycles is very small (only 0.05%).
- ±50mSec = Maximum variation can be 50 milliseconds.
Recovery time: 2Sec minimum
- It means, after one timing cycle finishes or after power OFF/ON,
- The timer needs at least 2 seconds before it can start working correctly again.
OTHER SPECIFICATION✅
Dimension 200 × 130 × 45 mm (W × H × D)
It means the physical size of the device.
- W (Width) = 200 mm (side to side size)
- H (Height) = 130 mm (top to bottom size)
- D (Depth) = 45 mm (front to back thickness)
The device is 200 mm wide, 130 mm tall, and 45 mm deep. This helps in planning panel mounting space and installation clearance.
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| Dimensions |
Ambient Conditions
It specifies the environmental conditions in which the device can safely operate and be stored.
Operating Temperature -10°C to +55°C
- The device will work properly when the surrounding temperature is between -10°C and +55°C.
- The device can be safely stored (not powered ON) within -25°C to +80°C without damage.
- The device can operate in environments with humidity up to 85% Relative Humidity at 40°C (non-condensing condition usually assumed).
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| Ambient Conditions |
The device can work in normal industrial temperature and humidity conditions, but should not be used or stored outside these limits to avoid damage or malfunction.
Service Life (Under No Load) 10⁶ Operations Minimum
- It means the device is designed to perform at least 1,000,000 operations (1 million cycles) when it is operating without any load connected to the output.
- The device relay can switch ON and OFF at least 1 million times when no load is connected. With load connected, the life may be lower depending on load type.
Electrical Life (Under Full Load) 10⁵ Operations Minimum
- It means the device relay is designed to perform at least 100,000 operations (1 lakh cycles) when switching at its rated full load condition.
- When the relay is switching real load at rated capacity, it can switch ON/OFF at least 100,000 times. This is lower than no-load life because load causes contact wear.
SAFETY PRECAUTIONS✅
- All safety precautions and instructions must be thoroughly read and followed prior to installation, commissioning, and maintenance of the equipment.
- There is a potential hazard of electric shock, explosion, or arc flash. Appropriate Personal Protective Equipment (PPE) must be used, and standard electrical safety work practices must be followed at all times.
- Installation and servicing must be carried out only by qualified electrical personnel after completely reviewing all provided instructions.
- If the equipment is not used in accordance with the manufacturer’s specified guidelines, the protective features of the equipment may be compromised.
- Personnel must never work alone while handling electrical equipment.
- The reliable performance of this equipment depends on correct handling, installation, and operational practices.
- Failure to follow proper installation procedures may result in personal injury, damage to equipment, or property loss.
- External fusing must never be bypassed under any condition.
- Failure to comply with these instructions may result in serious injury or fatality.
- EAPL shall not be held responsible for any consequential damages arising from improper use of the product.
- The product is designed and manufactured using carefully selected and proven electrical technologies.
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| Personal Protective Equipment |
Tools and Fasteners
- Use a star-type screwdriver for proper tightening of terminal screws.
APPLICATIONS
- Bag Filter systems,
- Dust pollution systems,
- Air handling systems,
- MCC panels,
- Pneumatic Conveyors,
- Process industries and many more.
ABBREVIATIONS & FULL FORM:
EAPL - Electronic Automation Private Limited
w.r.t - with respect to
AC - Alternating Current
DC - Direct Current
UL - Underwriters Laboratories
Hz - Hertz
MΩ - Mega Ohms
VA - Volt-Ampere
mSec - milliseconds
PPE - Personal Protective Equipment
In the next article, we will cover the wiring connections, programming procedure, and parameter settings of the EAPL ST-6M1 Sequential Timer.
Conclusion:
- The EAPL ST-6M1 Sequential Timer is a reliable multi-channel timing control solution designed for industrial automation applications requiring precise sequential load operation. With wide supply voltage compatibility, stable timing accuracy, strong insulation protection, and robust relay output capability, the device is suitable for demanding industrial environments.
- Proper installation, correct load selection, and adherence to safety practices ensure long service life and reliable performance in automation panels, dust control systems, and process industries.
About the Author – Insight Control System
Insight Control System provides technical education and practical guidance in the fields of Building Automation Systems (BAS), HVAC controls, PLC programming, sensors, and industrial automation. The content published on this platform is based on field experience, technical documentation analysis, and real-world system applications.
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