Transaction Overrun for property.... Property Transfer
Hi to All,
After create property transfer and work with this, showed in Service Event List:
"transaction overrun for property ..." See please image attached,
have any idea why appear this event message?
Voted best answer
Name itself telling "transaction overrun for property" means look at the update rate of both group of property trasnfer here before one group before ending another group starting so please instead putting 3002 & 3003ms here since no offset is possible all properties in agroup try to update in a pre-defined rate so try to increase the update rate to 3100ms & 3200ms respectively so that there is 100ms diffrence between two update rates.
Why are you using 3002, 3003 milliseconds etc.
Property transfer can transfer quite large amounts of data and is likely more efficient when the data is all together. Set the transfer time to 3000 mS.
The overrun likely indicates that one group has not finished before the next group needs to run. Which will tend to happen when you try to break up your cycle times by adding 1 or 2 ms to the end. You cant really break up a scan like this, they will still all trigger at the same time occasionally. There is no offset feature in property transfer.
Hi to all, in first place thanks very much for helps..
We create four property transfer: EB1, EB2, EB3 y EB4, everyone with update rate different (1500, 1750, 2500 and 2500 ms), but only EB3 and EB4 genered one event list, see new image attached.
This warning menssage is a condition that affects the normal performance in the system? or is only a message?
Its more than "only a message". Some data is late because the system is busy transferring the previous block of data. I assume that you are trying to load spread your Property Transfers by giving odd update intervals, like 2750 ms, but this is actually causing your problems.
Check your OPC server update rate settings using the OPC Server Configuration (in the task bar of the Connectivity server and probably also on the desktop). Typically your AC800M OPC server will be set up to create groups of "fast", "slow", "string" etc at intervals of 500ms, 1 second, 2 seconds, 10 seconds etc. ( you should not change these unless advised by ABB support or a specific product installation )
Your Property transfer update rates should match the settings in your OPC configuration settings. The Property transfer update rates should be an integer multiple of one of the update rates configured in your OPC server. 2750ms is not a multiple of the standard update rates.
For other DCS systems, like AC450 it is important that your property transfer rates match the OPC update rates for that DCS. So for AC400 series only ever use 1 second, 3 seconds , 9 seconds etc. for MOD300 typically use 4 seconds
Transaction overrun is often due to that the source OPC server is sending updates faster than the destination can handle. Most OPC servers I deal with have a 1:100 ratio or worse in write performance vs read performance.
Increasing the update rate is the first countermeasure one should consider.
We've also seen bogus overrun messages emitted by the STANDBY service provider in a redundant configuration. For sure, standby means no writing and such messages can be disregarded from. Restarting the standby service provider will resolve the nuissance messages.
The Property Transfer service was implemented to handle a limited number of transfers in a "best effort" practice; packing of multiple single updates into larger "parcels" or other performance improving functions does not exist in today's version.
The latest revision of 5.1 contain some improvements to the matter, e.g. rewrite on failure and a "refresh write" that can be set on a slow rate to force all properties to be written once in a while even if no changes are received from the source. This will make the property transfer a little bit better than sending a post card between two continents (read Windows PC to another Windows PC).
For high reliability and/or high speed links - do not use Property Transfer; resort to some fieldbus, e.g. MODBUS (TCP).