Digital Loggers

Advanced Power Control - Scripting

On its own, a power switch isn't very smart.  Add custom functionality using the built-in BASIC scripting language. It's really simple. No programming experience is required.  Have a look at the sample scripts.  Give it a try.  Need help?  Call (408) 330-5599 or send an email.  For scripting a WiFi enabled product click here.

Hardware Requirements

User-defined program scripts are stored in non-volatile EEPROM.  The Web Power Switch 7, DIN Relay III, C-13 Power switch, and Ethernet Power Controller III include expanded EEPROM.  On early units built before 2011, a memory upgrade may be needed for script storage.    Script controlled LCD, clock-calendar, metering, and RS-232 transmission functions are limited to products with corresponding hardware features installed. 

Entering Scripts

First, review the commands and samples below for a quick overview of the BASIC script language.  Log in as admin and use the Scripting link to access the programming page.  After entering a command on each line, press EDIT, or just return and the command will be copied.  If there's a syntax error in the command, the screen will refresh without changes. After you've entered a script, check the "Enable Scripting" checkbox.  Once enabled, start the script using the RUN button or any other method below.

Supported Commands

You may enter up to 127 of the commands below.  Commands are executed in sequence with a "step delay" between each command.  The step delay can be as short as 1 second (one command per second) or slower if you desire. Enter BASIC commands from the list below one at a time in the Script Listing section on the page http://Your_IP/script.htm.  Press "Edit" after entering each command.

Multiple Threads

For advanced users:  A thread is a process. You can run a multiple programs, or the same program up to 63 times simultaneously.  Multiple programs may be run by multiple threads. Code space is shared.  Up to 63 threads may run concurrently.  Be careful when starting threads, it's easy to start multiple simultaneous threads unintentionally.

Starting Scripts

There are several ways to start scripts: 


Enabling/Disabling Scripting

You must disable scripting (uncheck the enable box) to stop all threads before editing scripts.  You must enable scripting before any script will start.  Pressing the hardware reset-to-defaults switch resets to the default login and disables scripting.   Instead of clicking "EDIT" after entering each command, you can just press enter.

Stopping a Script

A script terminates automatically when the END command is reached. Click STOP ALL THREADS to stop everything manually.  You can also stop all scripts via http using http://Your_IP/script.cgi?stop

Relay Debounce Warning

Even with the scripting step delays, it is possible to create a script which will rapidly cycle a relay. This rapid cycling could result in a over current condition, tripped breaker, or stress to the power controller or attached equipment. To protect against damage to attached equipment or to the power controller,  the response time of attached relays is  limited by hardware to about ~500ms in newer products.  Before running multiple threads, please test your script.

Scripting Commands (Instructions)

Parentheses indicate variables. Enter just the variable without parantheses.  For example, AUTOPING 1 will look for the IP address stored in string 1.


This command enables autoping at the IP address specified in string N.  For example, if STRING 1 is, AutoPing will run (per the settings on the SETUP page) at that IP address.  Note that AutoPing operation begins only after a series of successful pings are used to establish a reliabile connection.

NOP No operation

Useful as a debugging command, delay, or branch target.  Causes a delay equal to the program step delay. Equivalent to SLEEP 0

END Ends execution

Terminates thread. Only one thread is stopped.

RUN (L) Create Thread

Create a new execution thread at line number (L)

GOTO (L) Branch

Unconditional branch to line (instruction) number (L)

GOSUB (L) Subroutine Call

Calls a subroutine at line (L)  Used with RETURN.


Execution will continue on the line following the calling GOSUB after the RETURN instruction is reached. Note: Subroutines are "emulated" by new execution threads. The parent counts as a thread.  63 simultaneous threads are allowed.

ON (NN) Activate Relay

Turns relays on. ie. ON 123 Turns on 1,2,3 leaving
4-8 unaffected (NN) is a list, ie ON 1357 sequentially turns odd outlets on.  To prevent excessive inrush currents, the sequence delay timer (On Sequence Delay value in the delay section of the setup page)  is used for multi-relay ON instructions.  In a DIN Relay, activating a relay closes the NO contacts and opens the NC contacts.

OFF (NN) Deactivate Relay

Turns relays off, ie. OFF 123 Turns off 1,2,3
leaving 4-8 unaffected.  OFF commands act immediately.  In a DIN Relay, deactivating a relay closes the NC contacts and opens the NO contacts.

RESTORE Restores All Relays

Restores all in numeric sequence relays to the
settings before power loss, ie."pre-powerloss" state. Sequence delay timing applies.

CYCLE (NN) Cycles Relays

Turns relays OFF, then ON, ie. CYCLE 13 reboots outlets 1 & 3  The relays are off for a period of time specific in the SEQUENCE DELAY field.

BEEP (T) Activate Beeper

Activates audio alarm in units so equipped, such as the Web Power Switch  7 Use BEEP ON to start a continuous alarm, BEEP OFF to stop the alarm.   The beeper can also be activated for 1-254 seconds with BEEP, ie. BEEP 120 will start the beeper for 120 seconds.  BEEP 0 is equivalent to BEEP OFF.  Beep 255 is equivalent to BEEP ON.  More on the beeper here.

SLEEP (T) Sleep Delay

Causes a delay.  Delay length can be specified in hours, minutes or seconds.  Useful for periodic tasks like weekly reboots.  See the scheduling page for more information,
Usage:  SLEEP 1 S  sleeps for one second
               SLEEP 2 H  sleeps for two hours
               SLEEP 3 D  sleeps for 3 days
               All numeric ranges are 0-255

LOG ($) Report to Syslog

Sends string variable ($) to a the selected SYSLOG server at the IP specified on the Setup page.

DISPLAY ($) Display Text on LCD

Sends a string ($) to the LCD display (on products so equipped).  See formatting commands below.


Sends string ($) to RS-232 Port 1 on Ethernet Power Controller II/III products, and to the internal TTL serial port on other products.  Serial ports may be used to configure or restart routers, Linux machines, UPSs, or to send messages to via modem or SMS.   The LCD is organized as two lines of 16 characters each.   Find more information on the serial ports here.

String Variables

A literal string may be entered directly, ie. "HELLO WORLD". A string may also include text generated by the power switch.  These strings are automatically generated and updated by the power switch:
  •  - literal "%"
  • %a - current Bus A
  • %A - voltage Bus A
  • %b - current Bus B
  • %B - voltage Bus B
  • %o - Outlets state in the form "12456" (ON are displayed)
  • %O - Outlets state in the form "++-+++--"
  • %n - Serial number
  • %f - Firmware version
  • %d - System time/date
  • %M - MAC address of the power controller
  • %i - IP address of the power controller
  • %m - IP network mask
  • %g - IP gateway
  • The LCD display or serial port  may be controlled using these formatting commands, known as "\" escape sequences. They are useful for PRINT and DISPLAY commands.  The LCD is organized as two lines of 16 characters each.  Below is the list of the sequences and their effect on the LCD display.


  •  - prints the literal "\" character to the LCD
  • \1 - position cursor line 1 beginning 
  • \2 - position cursor line 2 beginning
  • \f - clear LCD screen
  • \n - new line (formatting comand)
  • \r - carriage return (LCD does not scroll) (formatting comand)
  • \v - clear to the end of the current line
  • (formatting comand)


    TIME ($)

    Synchronize with an NTP server specified by its IP address (string $). A special value of 0 is reserved for synchronization with an internal battery powered Real-Time-Clock (RTC) chip, if present. This function is added in firmware versions 1.6.1 and later.  Battery powered RTC's are installed in the Ethernet Power Controller II-III, C-13 power switch, Web Power Switch 6+ and some other products.  Useful in conjunction with scheduling.  Available in firmware versions 1.6.x and later.


    KILL (NNN)

    Kills (shuts down) all threads started at line number NNN but the current thread. KILL 0 kills all threads.  Available in firmware versions 1.6.x and later.


    WAIT ($)

    Unlike the SLEEP command which just rests for a period of time, this command waits until a specific time and date (set by the real-time-clock) arrives.  Specify a time in the  ($) field, and when it matches the clock time, execution will resume on the next line following the WAIT command.  This function is available in firmware versions 1.6.x and later. The time format resembles that of a popular crontab entry, five fields separated by spaces. Each field is either an asterisk (meaning any) or a number. This "wildcard" feature lets you start programs periodically, for example once an hour, once a day, once a week, only on Friday the 13, etc.  Possible ranges are:

    1 Minute 0-59
    2 Hour 0-23
    3 Day of month 1-31
    4 Month 1-12
    5 Day of week 0-7 Sunday is 0 or 7

    Note, that the condition is satisfied if all fields match. For example the script

    1 ON 3
    2 WAIT 00 12 13 * 5
    3 CYCLE 3
    4 GOTO 2

    will reboot the server connected to the outlet 3 each noon Friday the 13th.


    WOL ($)

    Send a Wake On Lan command to the PC specified by its MAC address (string $).
    MAC address can have the XX:XX:XX:XX:XX:XX or XX-XX-XX-XX-XX-XX format.
    This function is added in firmware versions 1.5.2 and later. More information can be found here.


    Sample Scripts

    Automatically Reboot a Router, Display the Results, Send a SYSLOG Report

    This script pings through the router to an external server farm, in this case Google's multicast name servers,  Lines 1-3 start the autoping process and display a message on the LCD.  When the connection is lost (see the AutoPing page), it is assumed that the router has failed, so it is rebooted. Execution on line 5 is triggered by AutoPing settings.

    Status is displayed to the LCD using the DISPLAY commands on lines 2,5 and 6.  Line 7 performs the actual reboot by cycling power to outlet #1.  Line 8 gives the router and network some time to recover before monitoring starts again.  A message is sent via SYSLOG to the admin with the command on line 9.

    The program repeats in an infinite loop, and starts automatically on every power-up.

    Print Text to the LCD

    This program clears the LCD and displays the IP address, ie. IP= on the first line of the LCD.  Then it activates the beeper for one second and ends.  Since it starts on line 1, it will run every time the unit is powered up.  If you didn't want it to start on power-up, just begin on line 2 and leave the END function on line 1.

    Display Power Status on LCD

    This example displays the voltage and current readings on Bus B (using the meters in the Ethernet Power Controller).  The reading is updated every 5 seconds.

     Ring School Bells at 8AM on Mondays


    In this example (derived from an actual customer use), a DIN Relay is used to ring a school bell every Monday at exactly 8AM.  The DIN relay first syncs to a public time server, then it waits until 08:00 on a Monday.  After that, it rings the bell attached to relay 1 for a few seconds.

    AutoPing Example - Restart Devices and Phone Home

    In this example, a script is started as a result of loss-of-connectivity detected by AutoPing.  This script uses an AutoPing failure to reboot equipment and report the failure via dial-up modem connected to the RS-232 port on an Ethernet Power Controller.

    Note: Several AutoPing targets can be "joined" so that the task (be it a script or simple outlet[s] reboot) will be performed only if one of the targets responds. "Joining" requires autoping target tasks be identical. Joined targets can be "split" to work individually.

    Power Monitoring and Reporting to Syslog

    Clicking RUN 1 starts a loop which reports the voltage and current from an Ethernet Power Controller on each bus every 10 minutes to a SYSLOG server. Enter the destination address of the syslog server on the setup page.  What better way to bill your clients for power?  Well, you could also use our free Windows power monitoring utility.

    Starting the AutoPing Function on Power-up

    This is a common application.  Since the program starts automatically on LINE1 after power-up, this program will activate AutoPing on the IP address whenever power is restored.

    Starting AutoPing on Power-up and Restarting it Daily

    Since scripts start automatically on LINE1 after power-up, this program will activate AutoPing on the IP address whenever power is restored.  It will then "sleep" for a day and restart AutoPing automatically the next day.  Useful if a device should be restarted later after it exceeds the "maximum number of attempts to restart" set on the AutoPing page.

    Fish Tank Controller

    A local pet store uses code just like this to conserver power by controlling lights, air pumps and filters.  How does it work?  Lines 2-3 start two separate threads.  Each thread turns a separate outlet on and off at a programmed rate in an infinite loop.

    Simple Lighting Economizer

    This simple program shuts the lights off at 9:30PM daily.  Users can turn them on using a web browser.  Should they forget to turn them off, the power switch takes care of it.


    Have a smart script or unique way to use your switch?  We'll acknowledge your contribution.