Public Holiday in Controlgix

rommel.matheou · May 11, 2020

Hi,

Would like some help on how to determine a public holiday in the controllogiox calendar or other methods that have been used successfully in the past?

Ken Roach · May 11, 2020

Welcome to the PLCTalk forum !

ControlLogix has a "Wall Clock Time" function, which will give you the Year, Day, and Month.

But a schedule of public holidays would have to be hard-coded, or determined by some other sort of middleware, generally one that has access to the Internet.

Because it's my quarantine-time tech toy, I would probably automate something like this in Node-Red on a small Linux box.

doomsword · May 11, 2020

rommel.matheou said:
Hi,

Would like some help on how to determine a public holiday in the controllogiox calendar or other methods that have been used successfully in the past?

Public holidays for what country?

I think you could program easily for those holidays that are on same day in the calendar. I don't know how you would guess when is Easter this year.

Maybe you have some HMI or some computer communicating with PLC? Probably you could make a script that could tell to the PLC when is public holiday.

JordanCClark · May 12, 2020

Raspberry Pi using Python, the holidays library, and our very own dmroeder's PyLogix library.

Code:

#!/usr/bin/env python3

# Write to a Logix PLC tag named 'Holiday_Flag' whether the date is a holiday or not.

from datetime import date
import pylogix, holidays

ipAddress = '192.168.141.126'
tagName = 'Holiday_Flag'

# Create the holiday object for a particular locale.
holidayObject = holidays.UnitedStates()

# Test if today is a holiday
holidayFlag = date.today() in holidayObject

# Write the holiday status to the PLC tag
with pylogix.PLC() as comm
	comm.IPAddress = ipAddress
	comm.Write(tagName, holidayFlag)

glennz · May 13, 2020

First use GSV to get the WallClockTime object into a UDT tag with elements containing two-digit year, month and day of month in INTS. Call them YR, MO and DY.

The holiday calendar is then easily done with another tag of type DINT in an array of [100,13,1]. The Dimension 2 represents the two-digit year, Dimension 1 is month (1-12) and Dimension 0 DINT bits represent the day of month, 1-31.

You'll need to code the bits in the array to represent the calendar you desire. In my case logic 1 represented an 'on-peak' day for the local electric utility, M-F except American holidays; so the Wednesday May 13, 2020 bit represented by array location [20,5,0].13 would be logic 1. Somewhere in the past I came up with an Excel calculator to provide the DINT values for each month in the array automatically (i.e, value 1014823410 was for May 2020) but since lost it. I'm in the process of writing a one-time Ladder Routine to index through my array and automatically fill in all 99 years. That looks like it will be fairly easy for my utility using American holidays.

Once the array values are set, a single rung of indirect referencing the array bits using your WallClockTime tag can be used to check if today is a holiday (or whatever):

XIC calendar_tag[YR,MO,0].[DY] OTE is_holiday_tag

Ron Beaufort · May 13, 2020

seasoned advice ...

not certain exactly what you're attempting to accomplish with this project - but whatever you come up with - make SURE that you have an automatic "override" available ...

I've personally run into several situations over the years where the computer running things has been programmed to shut everything down - regardless of any "emergency" orders that have to be processed ...

I've been locked out of the office building that I rented because the computer system had Labor Day programmed as an official "holiday" - so no one should need to get into the building ... (wrong answer ... Ron still had to labor - even on Labor Day) ...

I've sweated buckets while rolling all of my training lab equipment into a cavernous automotive plant - since the computer had decided to turn off the air conditioning system over the weekend ... (no one knew how to bypass the stupid thing) ... even the fans were off ...

I could go on - but I've made my point ... feel free to ignore me if you like ...

party on ...

BachPhi · May 14, 2020

glennz said:
First use GSV to get the WallClockTime object into a UDT tag with elements containing two-digit year, month and day of month in INTS. Call them YR, MO and DY.

The holiday calendar is then easily done with another tag of type DINT in an array of [100,13,1]. The Dimension 2 represents the two-digit year, Dimension 1 is month (1-12) and Dimension 0 DINT bits represent the day of month, 1-31.

You'll need to code the bits in the array to represent the calendar you desire. In my case logic 1 represented an 'on-peak' day for the local electric utility, M-F except American holidays; so the Wednesday May 13, 2020 bit represented by array location [20,5,0].13 would be logic 1. Somewhere in the past I came up with an Excel calculator to provide the DINT values for each month in the array automatically (i.e, value 1014823410 was for May 2020) but since lost it. I'm in the process of writing a one-time Ladder Routine to index through my array and automatically fill in all 99 years. That looks like it will be fairly easy for my utility using American holidays.

Once the array values are set, a single rung of indirect referencing the array bits using your WallClockTime tag can be used to check if today is a holiday (or whatever):

XIC calendar_tag[YR,MO,0].[DY] OTE is_holiday_tag

How do you get it to UDT with 2 digit year without intermediate step?

glennz · Jun 1, 2020

Sorry, I thought that part was obvious. Math.

<DateTime_tag.Year> - 2000 = <TwoDigit_Year_tag>

I put in an ABS instruction to protect against a negative value at <TwoDigit_Year_tag> since it's used as an indirect addressing pointer. That can happen if the RTC is at it's default value (1999-something).

ASF · Jun 1, 2020

glennz said:
Sorry, I thought that part was obvious. Math.

<DateTime_tag.Year> - 2000 = <TwoDigit_Year_tag>

I put in an ABS instruction to protect against a negative value at <TwoDigit_Year_tag> since it's used as an indirect addressing pointer. That can happen if the RTC is at it's default value (1999-something).

Or you could use

Code:

DateTime_tag.Year MOD 100

which would cover you for the negative result and work indefinitely, instead of breaking in the year 2100 when I'm six feet under.

Public Holiday in Controlgix

rommel.matheou

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Ken Roach

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doomsword

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JordanCClark

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glennz

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Ron Beaufort

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BachPhi

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glennz

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ASF

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