intialising totaliser vaue in T640

Hi,

What could be reason of intialising totaliser vaue in T640 in the event of a power failure ?

As I undrstant that totaliser is backed up by RAM memory RAM, which is maintained by a Supercap in the T640 and warm start occurs the database is the one in RAM. means that the T640 resumes its exact control conditions in the event of a power failure of up to 24 hours.

Thanks
Ravikant
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  • Ian Roughsedge (Product Manager - Systems) May 28, 2013 06:42
    The T640 does have a Warm Start capability as you describe. But to use it, it must be enabled and so it is probably worth starting your checks with:

    - switch settings
    - cold start time

    First look at the switches that enable Warm and Cold Start. For the type of system you describe, it is usual to have both ON. You do not have to remove the T640 from its sleeve to view the switches; they can be seen online in the header block status field using the T640 front panel INSpect mode or through LINtools online connect.

    The image below is from LINtools configurator and so the switch setting are shown as FALSE (OFF), you would normally need TRUE (ON) for the type of application you describe.

    Second, check the Cold Start Time which is in minutes. So if you need 24 hours then set that to 24*60=1440 minutes, I notice the deafult is 0.0 mimutes (zero). Again, you can use the T640 front panel INSpect mode or LINtools online connect to investigate.

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  • Ian Roughsedge (Product Manager - Systems) May 28, 2013 06:55
    When working with Warm Start to preserve data like totals, do remember to consider real outputs (analogue and digitals) and what they might do in the event of a warm start.

    For example, if you enable warm start, what is the consequence? Could a control loop power up in closed loop mode and start driving an output after a 12 hour power outage? Is that desirable or not? The answers are often application dependant so you must consider them in the context of the use of the T640.

    You can make use of features in the T640 to help you manage this:

    - power failure detection via logic
    - power failure response though standard options.

    The T640 header block provides a pulsed logic signal to flag that a power falure has occurred, you can wire this to your control scheme and logic to take action on power fail recovery.



    Some standard function blocks (e.g. MODE and AN_OP) provide power options that can be used in some applications. Example below:

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  • Ian Roughsedge (Product Manager - Systems) May 28, 2013 07:03
    The T640 front panel INSpect mode is mentioned above, for this to operate it needs to be enabled either from a standard infrared key, or from user logic settings in the header block options.

    If you have a spare digital input then it can be useful to connect that to 'T640.Options.NoKeyFul' and so give conditional access to the INSpect mode via real digital input e.g. from a key switch.

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