# Expression evaluating as N/A **URL:** \ **Category:** Ignition\ **Created:** [May 17, 2010, 11:48am UTC](https://forum.inductiveautomation.com/t/expression-evaluating-as-n-a/1848 "2010-05-17T11:48:47Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![kacarmich](https://avatars.discourse-cdn.com/v4/letter/k/e5b9ba/32.png) [@kacarmich](https://forum.inductiveautomation.com/u/kacarmich)\ **Post date:** [May 17, 2010, 11:48am UTC](https://forum.inductiveautomation.com/t/expression-evaluating-as-n-a/1848/1 "2010-05-17T11:48:47Z")
In the SQL bridge, I am trying to use an hour meter which is based on the expression: if({[.]DOWNTIME\_TRIGGER}=0,0,1), which causes the meter to be active when the DOWNTIME\_TRIGGER=0, and resets the meter to 0 when the DOWNTIME\_TRIGGER=1. DOWNTIME\_TRIGGER is an OPC item. If I lose communication with that item, i.e., the power is shut down to that PLC, it evaluates as N/A. No matter what I have tried with expressions for my hour meter, I always get N/A when the DOWNTIME\_TRIGGER is N/A. Is there a good way around this? Thanks. ---
**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\ **Post date:** [May 17, 2010, 6:59pm UTC](https://forum.inductiveautomation.com/t/expression-evaluating-as-n-a/1848/2 "2010-05-17T18:59:09Z")
The problem is when the device is disconnected the quality of the tag or expression is bad. So, you can just force the quality to be good using the forceQuality expression function:`forceQuality(if({[.]DOWNTIME_TRIGGER}=0,0,1), 192)` I hope this helps. ---
**Author:** ![kacarmich](https://avatars.discourse-cdn.com/v4/letter/k/e5b9ba/32.png) [@kacarmich](https://forum.inductiveautomation.com/u/kacarmich)\ **Post date:** [May 17, 2010, 7:30pm UTC](https://forum.inductiveautomation.com/t/expression-evaluating-as-n-a/1848/3 "2010-05-17T19:30:06Z")
Yes. That solves it. Thanks!