ci-server-engineer/.claude/skills/system-management/tasks/read-write-item.md
cliu 1c3558c37c Complete phase 1 and build the CI-Eng-Sample project
Add verified system-management tasks (item read/write, quick load
records, history load, monitoring processes, consistency check, tuning
checks), the importable CI-Eng-Sample project with load/remove scripts,
the unlicensed 1-hour shutdown note, and the sample-project re-test
rule. Close ISS-002/003/004 and log ISS-005..007.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-30 14:01:33 +10:00

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---
task: Read and write item values with itmval
version: R1.03
source: IM 36K10J10-01EN §2.9.2; practiced on the test system and CI-Eng-Sample 2026-09-30
status: verified
---
# Read and write item values (itmval)
Needs CI Server running. Reading is read-only. **Writing changes live data**: follow the
user's chosen way of working (direct vs prepare only) and never write to an item that drives
real equipment without explicit approval.
Item names are full paths: `<Section>.<Sub-section>.<Tag>`, e.g.
`CI-Eng-Sample.TANK1.INFLOW` from the sample project.
## Read the current value
```
itmval -g -n <Section>.<Tag>
```
Output:
```
Value = 130
Status = 9
Options = 0xffffff88.00 ack
Quality = 0
```
- **Status** is a number from `STATUS_DF` (export it with `dssqld -e status_df.qli -d STATUS_DF -c`
to look numbers up). Common ones: 9 `NORMAL`, 13 `NOT INIT` (never written; new items start
here), 4 / 5 `BOOLEAN 0` / `BOOLEAN 1`, 11 `HIGH HIGH`.
- **Options** lists item flags as words after the hex value, e.g. `ack` (acknowledged),
`off` (item's station not communicating). `uoff` also appears on station items after a write;
its meaning is not yet known (see `knowledge/issues.md` ISS-001).
## Read limits
```
itmval -g -n <Section>.<Tag> -a <n>
```
`<n>`: 1 deadband, 2 low, 3 high, 4 low-low, 5 high-high. The limit is returned in `Value`.
Items with no limits configured return `ITM-E-WRONG_ATT, Wrong attribute number used`.
## Write a value
```
itmval -p -n <Section>.<Tag> -v <value> [-s <status>] [-q <quality>]
```
- Read the item first and note its value, so it can be restored.
- Booleans take `-v 0` / `-v 1`; the status follows automatically (4 / 5).
- `-s` sets the status explicitly (e.g. `-s 9` NORMAL). Without it, a numeric write gives 9.
- `-o` overwrites a blocked item; `-t [<date>] <time> [GMT|LST]` sets the timestamp
(default local civil time); `-e` writes to event history only, not the current value.
- Read it back to confirm.
## Verified examples (CI-Eng-Sample)
| Command | Result |
|---|---|
| `itmval -p -n CI-Eng-Sample.TANK1.INFLOW -v 120.5` | Value 120.5, status 9 |
| `itmval -p -n CI-Eng-Sample.TANK1.INFLOW -v 130 -s 9` | Value 130, status 9 |
| `itmval -p -n CI-Eng-Sample.PUMP1.RUNNING -v 1` | Value 1, status 5 (BOOLEAN 1) |
| `itmval -g -n CI-Eng-Sample.TANK1.LEVEL -a 2` / `-a 3` / `-a 4` / `-a 5` | 20 / 80 / 10 / 90 |