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Questions on using watchdog for ELS61 and PLS62T-W-USB terminals | Thales IoT Developer Community

September 16, 2020 - 3:45pm, 2698 views

I have an existing application that issues AT command to a modem every couple of seconds.  We're currently using a modem that uses AT commands to enable, disable and reset (kick) the watchdog, and now plan to change to the ELS61 or PLS62T-W-USB terminal.  So I'm trying to figure out how to implement the watchdog function for the ELS61 and PLS62T-W-USB terminals without Java programming which I'm not familiar with.

According to the Cinterion_Java_Terminal_HID_v02_1-31-19.pdf guide, I'll need to configure the hardware watchdog using the RS232 interface, setting baud rate to 1200bps.

To configure the watchdog to reset the terminal if there's no serial data received from module for more than 5 minutes:

WD=RST_UART,300000,3
WD=MIN_START_TIME,600000,6
WD=ALWAYS_ON,30000,3

Since there's no feedback from the module, I'll need to wait for green LED light to flash before issuing the next command.

After the watchdog has been configured, I can use the command AT^SCFG="Userware/Watchdog","1" to enable, and the command AT^SCFG="Userware/Watchdog","0" to disable the watchdog.  Unlike WD commands, "AT^SCFG" commands can be issued using the USB interface.

Questions: 
1. Are my steps correct?
2. Does the terminal loses it's configuration after a Power Cycle.  Do I need to issue the commands again after each power cycle?  
3. Can I configure the hardware watchdog using the USB interface instead of sending WD commands using the RS232 TXD0 line? Some PCs today don't come with RS232 interface.  "Figure 18: Hardware watchdog configuration" says that it's possible to configure the hardware watchdog using the ASC0 interface, but I'm not able find some any instruction in the Java Terminal and AT Command Set guides on how I can do that using the AT^SSPI command.