From an s7 315-2 dp i need to send time stamped alrm messages to a wincc application. Does any one know how this is done in the plc and wincc. In the plc are the standard sfb's used?
Hi,
In libraries\standard library\ section under miscellaneous blocks\FB 62. It is a time stamp block. I haven't used it and it looks very involved to at first glance.
All I ever do is read the cpu time using SFC1, the output from this in DT format is place as a temp in the function header.
This temp variable is read by FC8 "DT_TOD" for time and FC6 "DT_DATE" in a DB address.
The time and Date can the be read out for the occurance of the event by moving the time for the event (on a rising or falling edge) into another DB or memory location.
This can repeated many times over just by using the "MOVE" function.
Hope this helps.
Regards,
Paul.
Hello, Hassan;
Normally, one would use the SCADA system detect that an alarm has occured in the PLC, and then log the timestamp (in WinCC) with the alarm message. This lowers the requirements on the PLC (reading the real-time clock everytime there is an alarm, converting the date/time values to string, transmitting the string to the SCADA....
In WinCC, you start by creating a tag linked to the alarm(s) you are planning to use in Tag Management.
You then start the Alarm logging editor, set-up the classes of messages you will use (here is where you include the timestamp format for the messages)and link the message/timestamp to a specific trigger (the alarm bit in the PLC for example).
In order to see the alarm messages, you must configure am Alarm page in the Graphic Editor, using the Alarm OCX smart object. You must also configure the starting of the Alarm server in the Computer Setup editor.
Hope this helps,
Daniel Chartier
I probably totally misunderstand your question... But I just have to say that all alarms configured in WinCC automatically get assigned a date and time stamp when they happen in the PLC(s).
So - just congifure the alarm tags in WinCC and WinCC will to the rest for you. The date and time that is assigned is (I think) assigned by WinCC according to the computer's clock - so if you definately need the time from the plc - then I don't know.
Standard sfb's are not neccessary.
First create a data block consisting of alarms levels in the plc.
Then create external tags in the wincc application that will referrence this locations.
In the wincc application,open alarm logging editor then configure the messages by using the created tags.
In the computer properties of the wincc application check alarm logging runtime.
A timestamp assigned to alarms by the SCADA/HMI software is not assigned "when they happen in the PLC". Rather, it is assigned when the SCADA/HMI software reads and interprets the PLC data, which depends on the configured poll rates, I/O comm latency, etc. For many applications, perhaps most, a SCADA-assigned timestamp is close enough.
For some applications, though, a true event timestamp from the PLC (or IED) is necessary. Take, for example, a system in which alarms tend to come in bunches, cascading from an initial event, and occurring a few milliseconds apart. It is possible (and in our example, likely) for a number of points to go into alarm serially between successive polls, even if the software grabs the data several times per second. If the SCADA/HMI software assigns the same timestamp to all the points in a single poll, it loses sequence-of-event (SOE) information, which can be critical to diagnosing what went wrong and why.
When using a PCVUE SCADA associated with an Applicom board,it is possible to get PLC time stamped variables. However you have to create a DB on your S7 for stacking events and a FB to manage this stack in accordance with the exchange protocol. This mechanism is usefull for electrical distribution where you need to sort events with a ms accuracy. Please visit our Web site www.arcinfo.com
