User's Manual

GWM400 Product Technical Specification and User Guide
3.5 Power Up/Power Down Scenarios
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 GWM400_HID_v02 2017-07-05
Confidential / Prelimenary
Page 23 of 38
3.5 Power Up/Power Down Scenarios
In general, be sure not to turn on the GWM400 while it is beyond the safety limits of voltage
stated in Section 4.1. GWM400 immediately switches off after having started and detected
these inappropriate conditions. In extreme cases this can cause permanent damage to the
GWM400.
3.5.1 Turn GWM400 on
GWM400 is automatically turned on and started into normal mode by plugging or by re-plug-
ging an appropriate power supply unit at the power supply line BATT+.
Every time before turn on the GWM400, it must be disconnected at least for 2 seconds from
power supply to ensure turn on properly.
3.5.2 Reset/Restart GWM400
GWM400 can be reset/restarted by entering the command AT+CFUN=x,1. For details on
AT+CFUN please see [1].
3.5.3 Turn GWM400 off
Normal shutdown:
• To turn off the GWM400 use the AT^SMSO command, rather than disconnecting the mains
adapter.
This switch off procedure lets the GWM400 log off from the network and allows the software
to enter a secure state and save data before disconnecting the power supply. After
AT^SMSO has been entered the GWM400 returns the following result codes:
^SMSO: MS OFF
OK
^SHUTDOWN
The "^SHUTDOWN" result code indicates that the GWM400 turns off in less than 1 second.
After the shutdown procedure is complete the GWM400 enters the Power Down mode. The
RTC is still fed from the voltage regulator in the power supply ASIC.
Only after power off and power on again, i.e., turning off and on the power supply line, can the
terminal be switches on again. Apart from the normal shutdown.
3.5.4 Disconnecting Power Supply
Before disconnecting the power supply from the BATT+ pin, make sure that the GWM400 is in
a safe condition. The best way is to wait 1s after the "^SHUTDOWN" result code has been in-
dicated.