Industry Online Support
Technical Forum
6/20/2006 6:57 PM | |
Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating: (318)
|
[quote user="Murray"] 1) We have 2 S7-312IFM CPU's in the factory and they are both losing their "production counts" which are stored in DB's on a mains reset. I thought that DB's didn't lose their data values when the isolator was switched off?? Is this a limitation of the CPU itself because our S7-313C CPU's don't lose their counts in DB's? I went into the hardware setup, to the "retentative memory" tab and there was 1 DB which you could set as retentative but it's already being used for important functionality values eg: timers. 2) Sometimes when I go into a CPU hardware setup and click on the "retentative memory" tab, all the areas under that tab are greyed out and you can't setup any retentative DB's?? Again is this a limitation of the CPU itself?? Surely then our 313C's should lose their counts? 3) I found out sometime last year that some of our PLC's have "software clocks" in them and not "real time clocks". IE: when the mains is switched off they stop ticking over. We are requiring certain timed functionality to store shift counts at specific times. Now I know we can't stop people switching off the mains, but we do have a PLC on the MPI network which has a real time clock. How do we "update" the software clock with the time from our "real time clock"?? IE: transfer the time from the real time clock, over the MPI network, to the software clock so it continues ticking over from the current time and not the time it stopped at? Hi Murray, About 1) This are the older CPUs which have no MMC, so they can't store anything about some space for 1 DB. About 2) The CPUs with a MMC can store the values after the power is down and so those CPUs didn't need to have retentive Datablocks. About 3) The PLC with the realtime clock have to be the master on the MPI network for the time. The other have to be switched to Diagnostics/Clock --> Synchronization On MPI "As Slave". See also the FAQ: Time synchronization in the SIMATIC environment via MPI-Subnets http://support.automation.siemens.com/WW/view/en/17521938 So i hope you have enough answers to work with the equipment. [;)] 3a) Time synchronization in the CPUs, see FAQ http://support.automation.siemens.com/WW/view/en/19866467 |
Last edited by: Late at: 6/20/2006 7:06 PMPut 3a) to the answer I hope that the answer will help, if you have still questions, don't hesitate to ask me. |
|
Follow us on