# Transaction Groups: Source Value vs Latched Value **URL:** \ **Category:** Ignition\ **Tags:** ignition80\ **Created:** [December 12, 2019, 8:16pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673 "2019-12-12T20:16:05Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![scicco](https://avatars.discourse-cdn.com/v4/letter/s/e0b2c6/32.png) [@scicco](https://forum.inductiveautomation.com/u/scicco)\ **Post date:** [December 12, 2019, 8:16pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/1 "2019-12-12T20:16:05Z")
Hello, I recently upgraded to Ignition 8 and noticed the Transaction Group Items boxes now have two columns for Value: Source and Latched. I can’t find anything in the documentation that describes the difference between the two. Can someone please elaborate on the difference and also what the benefit is of seeing both? I’m currently seeing discrepancies between the two so it’s confusing which value will be used when it’s triggered. ![Capture%205](https://us1.discourse-cdn.com/inductiveautomation/original/2X/5/5773bec22255f3cfe01f2e70894c4702a3eaa41e.png) Thanks - ---
**Author:** ![tejagovindula](https://avatars.discourse-cdn.com/v4/letter/t/ee59a6/32.png) [@tejagovindula](https://forum.inductiveautomation.com/u/tejagovindula)\ **Post date:** [January 7, 2020, 10:04pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/2 "2020-01-07T22:04:15Z")
Source Value is your Actual Value of the Tag. Latch Value is what you are writing to the database. Value first comes to Source and then goes to latch and goes to database. ---
**Author:** ![Mahin\_Ahmad](https://avatars.discourse-cdn.com/v4/letter/m/53a042/32.png) [@Mahin\_Ahmad](https://forum.inductiveautomation.com/u/Mahin_Ahmad)\ **Post date:** [September 10, 2022, 7:01am UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/3 "2022-09-10T07:01:54Z")
Can I do anything with the source value before it gets to latched value? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [September 10, 2022, 2:16pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/4 "2022-09-10T14:16:38Z")
Use an expression item instead of a tag or OPC item. ---
**Author:** ![tam.nguyen](https://avatars.discourse-cdn.com/v4/letter/t/a87d85/32.png) [@tam.nguyen](https://forum.inductiveautomation.com/u/tam.nguyen)\ **Post date:** [July 20, 2025, 9:47pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/5 "2025-07-20T21:47:22Z")
I have a problem with Latch Value. It insert to database previous value not current value. Any idea how to fix this issue? Thanks, Tam ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/9/d9a53eb8637a7603edb520071fc3473e21225b31.png) ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 21, 2025, 12:06am UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/6 "2025-07-21T00:06:02Z")
> [@tam.nguyen](#): > > It insert to database previous value not current value. > Any idea how to fix this issue? That commonly happens when a non-trigger item is a tag. OPC doesn't have ordered delivery, so a trigger could fire before the rest of the tags are "fresh". The answer is to replace the items that point at OPC tags with items that point directly at the OPC value, and set the transaction group to OPC "Read" mode. That causes a fresh read to happen just after the trigger, pulling in values that are certain to be "after" the trigger. ---
**Author:** ![tam.nguyen](https://avatars.discourse-cdn.com/v4/letter/t/a87d85/32.png) [@tam.nguyen](https://forum.inductiveautomation.com/u/tam.nguyen)\ **Post date:** [July 21, 2025, 3:22pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/7 "2025-07-21T15:22:25Z")
Thanks for quick relay. I am new Ignition. Where can I set the OPC to "Read" Mode. I can't find "Read" in the Mode as shown below Please! Advice Thanks, Tam ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/a/aacf2ba0374d0e20c050e3eeb3370ff903ebe1d8.png) ---
**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\ **Post date:** [July 21, 2025, 3:24pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/8 "2025-07-21T15:24:01Z")
Advanced settings, upper right window if using default designer layout. ![advanced-settings-46cf10d2cbde00cd7fe72f7772c704fc](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/8/182aed4a3ac82de6db6bfc3f36ff6ef29f96df74.png) > **[Understanding Transaction Groups | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/sql-bridge-transaction-groups/understanding-transaction-groups#advanced-settings)** > > Transaction Group Workspace Change OPC mode from `subscribe` to `read` ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 21, 2025, 3:26pm UTC](https://forum.inductiveautomation.com/t/transaction-groups-source-value-vs-latched-value/30673/9 "2025-07-21T15:26:19Z")
Remember that the change in OPC data mode does not apply to **tags**. You must replace those members in your transaction with OPC Items, typically dragged from the OPC Browser (not the Tag Browser).