Based on the UNIX CRON Time Scheduler

Version 9 firmware for the dataTaker DT80 datalogger includes a new time-based schedule trigger that is based on the UNIX CRON time scheduler. This powerful new schedule trigger type will greatly simplify many existing tasks and allow a greater flexibility in how and when a schedule is triggered. In our latest Technical Article, CAS DataLoggers and dataTaker show you how to program triggers into your DT80.

 

CRON—Time-Based Schedule Trigger

For use with dataTaker DT80 Firmware V 9.00 and up

CRON allows the dataTaker user to trigger a schedule:

  • At a specific time of day (e.g. At 9:00:00)
  • On a particular day of the month (e.g. First day of the month)
  • Run between specified hours in the day (e.g. between the hours of 9am to 5 pm)
  • Run between specified days of the week (e.g. Between Monday and Friday)
  • Run at a specified time before the minute or hour. (e.g. 1 minute before the hour)
  • Run at times listed (e.g. 1 am, 2 am, 4 am, 8 am etc.)
  • Run at any time built from the combinations above.

 

Syntax

Ra”Name”()[Sec:Min:Hr:Day:Month:Day of Week]

 

Where:

a = Schedule identifier

Name = Schedule name

= Store file definition

[ = Start of CRON expression

Sec = Second of the minute

Min = Minute of the hour

Hr = Hour of the day

Day = Day of the month

Month = Month of the Year

Day of Week = Day of the week

] = End of CRON expression

 

e.g.

RA“Schedule_1″(“b:”,ALARMS:OV:100KB:W60,DATA:OV:1MB)[*:*:9-17:*:*:1-5]

This example will sample once per second between the hours of 9 and to 5 pm Monday to Friday.

 

Valid Data Ranges

Each field in the Colon (:) separated list has a range of valid inputs:

  •  Second of the minute 0 – 59
  •  Minute of the hour 0 – 59
  •  Hour of the day 0 – 23
  •  Day of the month 1 – 31
  •  Month of the year 1 – 12
  •  Day of the Week 0 – 7 Note: Sunday is 0 or 7

 

Each field can also accept:

  •  A list of values 1,2,4,8,16
  •  A range of values 9-17
  •  A list of ranges 0-4,8-12
  •  All in the range *
  •  By steps of */2 or 0-23/2

 

Notes:

  •  Fewer than 6 fields may be specified. e.g. [0:9] is identical to [0:9:*:*:*:*] and means 9 minutes and 0 seconds past the hour, every hour, every day of the month, every month and every day of the week.
  •  Fields may not be empty. e.g. [0:9:::*:*] is not allowed.
  •  Must use 24-hour clock. e.g. 9 pm is not allowed, use 21
  •  Relative time addressing not allowed.
  •  The step size is up to the maximum range allowed for field type.
  •  Times are synchronized to midnight by the DT80 internal clock.

 

Examples:

Example 1 – Trigger schedule at 9:00:00

Returns the daily maximum, minimum and average of the air temperature at 9:00:00 every day for a PT100 RTD sensor sampled every 1 minute.

CRON expression:

Schedule A – [0:0:9]

 

BEGIN"9AMRPT"

RS1M 'SET STATISTICAL SAMPLE RATE TO ONCE PER MINUTE.

RA[0:0:9] 'SET SCHEDULE TO SCAN AT 9AM EVERY DAY

1PT385("AIRTMP~DEGC",MX)("AIRTMP~DEGC",MN)("AIR TEMP~DEGC",AV)

END

 

Example 2 – Trigger schedule every minute between 9:00 and 17:00

Sample a current loop device once per minute between the hours of 9 am to 5 pm seven days a week.

CRON expression:

Schedule A – [0:*:9-17]

 

BEGIN"9TO5"

RA[0:*:9-17] 'TRIGGER ON ZERO SECOND, EVERY MINUTE BETWEEN HOURS 9 TO 17

1L("DEMAND~%")

END

 

Example 3 – Trigger schedule every minute between 9:00 and 17:00 Monday to Friday

Sample a current loop device once per minute between the hours of 9 am to 5 pm Monday to Friday.

CRON expression:

Schedule A – [0:*:9-17:*:*:1-5]

 

BEGIN"9TO5WEEK"

RA[0:*:9-17:*:*:1-5]

1L("DEMAND~%")

END

 

Example 4 – Trigger schedule 10 seconds before the minute

Uses schedule A to turn on the power to a 4 to 20 mA sensor 10 seconds before the minute. Schedule B then reads the sensor and then turns off the power. This gives the sensor 10 seconds of warm up time before being read.

CRON expressions:

Schedule A – [50]

(Run at 50 seconds into the minute)

 

Schedule B – [0]

(Run on the minute)

BEGIN"PWRON"

RA[50]             'RUN ON SECOND #50

1SSPWR=1      'TURN ON THE POWER

RB[0]                   'RUN ON SECOND #0

1L("FLOW RATE~%")   'READ THE SENSOR

1SSPWR=0      'TURN OFF THE POWER

END

 

Example 5 – Trigger schedule at the end of each working week

Sample a current loop device once per minute between the hours of 9 am to 5 pm, Monday to Friday. On Sunday a weekly report is generated at midnight on Sunday morning, then the weekly tally is reset.

CRON expressions:

Schedule A – [0:*:9-17:*:*:1-5]

(Run 9am to 5 pm Monday to Friday)

 

Schedule B – [0:0:0:*:*:0]

(Run report Midnight Sunday morning)

 

BEGIN"WKRPT"

RA[0:*:9-17:*:*:1-5]

1L("KW",+=1CV)

RB[0:0:0:*:*:0]

1CV("WEEK TOTAL~KW",R)

END

 

Example 6 – Trigger schedule at the end of each month

Sample a current loop device once per minute between the hours of 9 am to 5 pm, Monday to Friday. A monthly report is generated at midnight on the first of each month, then the monthly tally is reset.

CRON expressions:

Schedule A – [0:*:9-17:*:*:1-5]

(Run 9am to 5 pm Monday to Friday)

 

Schedule B – [0:0:0:1]

(Run report at Midnight 1st of month)

 

BEGIN"MTHRPT"

RA[0:*:9-17:*:*:1-5]

1L("KW",+=1CV)

RB[0:0:0:1]

1CV("MONTH_TOTAL~KW",R)

END

 

Example 7 – Block/Range sampling 1

Sample a current loop device every second for the first 15 seconds of every minute.

CRON expressions:

Schedule A – [1-15]

(Sample second in the range of 1 to 15)

 

BEGIN"15SEC"

RA[1-15]

1L("KW",+=1CV)

END

 

Example 8 – Block/Range Sampling 2

Sample a current loop device every second for the first 15 minutes of every hour.

CRON expressions:

Schedule A – [*:1-15]

(Sample every second of each minute in the range of 1 to 15)

 

BEGIN"15MIN"

RA[*:1-15]

1L("FLOW",+=1CV)

END

 

Example 9 – List Sampling 1

Sample a current loop device on the minute for each minute listed.

CRON expression:

Schedule A – [0:1,2,5,10,20,40]

(Sample at minutes 1, 2, 5, 10, 20 and 40 every hour)

 

BEGIN"MINLIST"

RA[0:1,2,5,10,20,40]

1L("CONSOLIDATION~MM")

END

 

Example 10 – List Sampling 2

Sample a current loop device on the minute for each hour listed.

CRON expression:

Schedule A – [0:0:0,1,2,4,8,16]

(Sample at hours 1, 2, 4, 8 and 16)

 

BEGIN"HRLIST2"

RA[0:0:0:1,2,5,10,20,40]

1L("CONSOLIDATION~MM")

END

 

Example 11 – List of Ranges

Sample a current loop device on the minute for each minute listed.

CRON expression:

Schedule A – [0:*:1-3,6-9,12-15,18-21]

(Sample every minute between 1 am to 3 am, 6 am to 9 am, noon to 3pm and 6pm to 9pm every day)

 

BEGIN"HRRNG1"

RA[0:*:1-3,6-9,12-15,18-21]

1L("CONSOLIDATION~MM")

END

 

Example 12 – Interval Sampling 1

Sample temperature sensor every second minute.

CRON expression:

 

Schedule A – [0:*/2]

(Sample every second minute. e.g. at minutes 0, 2, 4, 6, 8, 10 etc.)

 

BEGIN"2MIN"

RA[0:*/2]

PT385("TEMPERATURE")

END

 

Example 13 – Interval Sampling 2

Sample temperature sensor 30 seconds past the minute every second minute.

CRON expression:

Schedule A – [30:*/2]

(Samples at 00:00:30, 00:02:30, 00:04:30 etc.)

 

BEGIN"2M30S"

RA[30:*/2]

PT385("TEMPERATURE")

END

 

Example 14 – Interval Sampling 3

Sample load cell on the minute every 6 hours.

CRON expression:

Schedule A – [0:0:*/6]

(Samples at 00:00:00, 06:00:00, 12:00:00 and 18:00:00 every day)

 

BEGIN"6HR"

RA[0:0:*/6]

1BGI("LOAD~PPM")

END

 

Error Messages:

E148 – Time Trigger – Invalid Characters in Trigger

 

Example 15. The code:

BEGIN"E148"

RA[*:*:*:*:JUNE]

REFT

END

 

Will return the message:

E148 – Time trigger – invalid characters in trigger at line 2 col 3 [ ra[*:*:*:*:J ]

Error due to the month being named. Only integer numbers are allowed in CRON schedule trigger definition.

E149 – Time Trigger – One or More Trigger Fields Overrange

 

Example 16. The code:

 

BEGIN"E149"

RA[60:*:*:*]

REFT

END

 

Will return the message:

E149 – Time trigger – one or more trigger fields overrange at line 2 col 3 [ ra[60:*:*:*] ]

Error due to the number of seconds entered as 60. Seconds’ field valid input range is 0 to 59

E150 – Time Trigger – Illegal Extra Character in One or More Fields

 

Example 17. The code:

 

BEGIN"E150"

RA[2S:*:*:*]

REFT

END

 

Will return the message:

E150 – Time trigger – illegal extra characters in one or more fields at line 2 col 3 [ ra[2s:*:*:]

Error due to the letter ‘s’ after the seconds’ definition. No characters are allowed.

E151 – Time Trigger – ‘Skip’ Value Overrange in One or More Fields

 

Example 4. The code:

 

BEGIN"E151"

RA[*/90:*:*:*]

REFT

END

 

Will return the message:

E151 – Time trigger – ‘skip’ value overrange in one or more fields at line 2 col 3 [ra[*/90:*:*: ]

Error due to the number of seconds to skip exceeding the valid range of inputs for the seconds field (0 to 59).

E151 – Time Trigger – Invalid Characters After ‘/’ in One or More Fields

 

Example 5. The code:

 

BEGIN"E152"

RA[*/-9:*:*:*]

REFT

END

 

Will return the message:

E152 – Time trigger – invalid characters after ‘/’ in one or more fields at column 3 [ra[*/90:*:* ]

Error due to the – character after the / in the seconds. Relative time addresses are not allowed.