Overview
This guide explains power management functions available on Siretta industrial modems. It covers modem power states, sleep modes, wake-up mechanisms, low power operation and design considerations for battery-powered and energy-efficient applications.
| Part Number | Description |
|---|---|
| ZETA-GEP-LTE4 (EU) | Low Power LTE Cat 4 European Modem with GPIO and GNSS |
| ZETA-NEP-LTE4 (EU) | Low Power LTE Cat 4 European Modem with GPIO |
| ZETA-N-LTE (EU) | High Performance LTE Cat 4 Modem with GPIO |
| ZETA-NSP-LTE1 (EU) | Low Power LTE Cat 1 Modem |
| ZETA-NLP-LTE1 (EU) | Ultra Low Power LTE Cat 1 Modem |
| ZETA-G-GPRS | GSM/GPRS Modem with GNSS |
| ZETA-N2-GPRS | GSM/GPRS Modem |
This guide demonstrates how to:
Expected Result
At the end of this guide the modem should be capable of operating in reduced power modes suitable for low power and battery-operated applications.
Industrial cellular modems typically support multiple operating states.
| Power State | Description |
|---|---|
| Full Operation | Modem fully active and connected |
| Idle Mode | Registered but inactive |
| Sleep Mode | Reduced processor and RF activity |
| Deep Sleep | Minimal subsystem operation |
| Power Off | Modem disabled |
Important Note
Supported power modes vary depending on modem series and firmware capability.
The modem power requirement changes significantly depending on activity.
| Activity | Typical Power Impact |
|---|---|
| Cellular transmission | Highest current consumption |
| GNSS operation | Increased RF power usage |
| Idle network registration | Moderate consumption |
| Sleep mode | Reduced consumption |
| Deep sleep | Lowest consumption |
Sleep mode reduces modem power consumption during inactivity.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CFUN=5 |
| Command | Description |
|---|---|
AT+CFUN=5 |
Enables low power functionality |
Important Note
Some modem functionality may be unavailable while operating in reduced power states.
The modem can be woken using:
| COM3 - Wake-Up Event |
¶ File Edit Setup Control Window Help |
|
AT |
Expected Result
The modem should wake and return anOKresponse.
Minimum functionality mode disables RF operation while keeping the modem partially operational.
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CFUN=4 |
| Command | Description |
|---|---|
AT+CFUN=4 |
Disables RF communication |
| COM3 - Tera Term VT |
¶ File Edit Setup Control Window Help |
|
AT+CFUN=1 |
| Command | Description |
|---|---|
AT+CFUN=1 |
Restores full modem functionality |
GNSS receivers can significantly increase power consumption.
| COM3 - GNSS Control |
¶ File Edit Setup Control Window Help |
|
AT$GPSP=0 |
Important Note
Disabling GNSS can significantly reduce power consumption in battery-operated systems.
Reliable modem operation requires a stable power supply capable of supporting transmission current peaks.
| Recommendation | Reason |
|---|---|
| Use low impedance supply | Prevent voltage drop |
| Add bulk capacitance | Support RF current peaks |
| Use short power cables | Reduce voltage losses |
| Avoid undersized regulators | Prevent resets |
| Provide adequate current margin | Improve stability |
For battery-powered applications:
| Stage | Power Optimisation |
|---|---|
| Wake modem | Temporary full operation |
| Transmit data | Cellular active |
| Receive acknowledgements | Short active window |
| Disable GNSS | Reduce RF usage |
| Enter sleep mode | Minimise idle consumption |
| COM3 - Functionality Query |
¶ File Edit Setup Control Window Help |
|
AT+CFUN? +CFUN: 1 OK |
| Response | Meaning |
|---|---|
1 |
Full functionality |
4 |
RF disabled |
5 |
Reduced functionality |
| Problem | Possible Cause | Solution |
|---|---|---|
| Unexpected modem resets | Power supply instability | Increase supply capability |
| Failure to wake | Sleep configuration issue | Verify wake conditions |
| Excessive current draw | GNSS or RF active | Disable unused functions |
| Network registration lost | RF disabled | Restore full functionality |
| Short battery life | Frequent transmission activity | Optimise sleep intervals |
| Step | Action |
|---|---|
| 1 | Configure sleep mode |
| 2 | Configure wake-up methods |
| 3 | Disable unused interfaces |
| 4 | Optimise RF activity |
| 5 | Disable GNSS if unnecessary |
| 6 | Monitor modem power state |
Support
For further assistance, please contact the Siretta support team.