cliu
ef543cde20
- Summary of IM 36K10C10 (Engineering Module - I/O Processes), checked against dssana.sup, itm.sup and the default datasets - New skill authorization: users and authorization groups by quick load - item-engineering: string item limits (1-200, holds length - 1) and the integration granule (itm_int_secs), both tested on CI-Eng-Sample - CI-Eng-Sample: read-only authorization group CIENG_VIEWER - Closed ISS-001 (uoff/ublk option bits), ISS-010, ISS-019; new ISS-018, ISS-020 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
71 lines
2.6 KiB
Markdown
71 lines
2.6 KiB
Markdown
---
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task: Read and write item values with itmval
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version: R1.03
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source: IM 36K10J10-01EN §2.9.2; practiced on the test system and CI-Eng-Sample 2026-09-30
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status: verified
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---
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# Read and write item values (itmval)
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Needs CI Server running. Reading is read-only. **Writing changes live data**: follow the
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user's chosen way of working (direct vs prepare only) and never write to an item that drives
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real equipment without explicit approval.
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Item names are full paths: `<Section>.<Sub-section>.<Tag>`, e.g.
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`CI-Eng-Sample.TANK1.INFLOW` from the sample project.
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## Read the current value
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```
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itmval -g -n <Section>.<Tag>
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```
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Output:
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```
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Value = 130
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Status = 9
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Options = 0xffffff88.00 ack
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Quality = 0
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```
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- **Status** is a number from `STATUS_DF` (export it with `dssqld -e status_df.qli -d STATUS_DF -c`
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to look numbers up). Common ones: 9 `NORMAL`, 13 `NOT INIT` (never written; new items start
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here), 4 / 5 `BOOLEAN 0` / `BOOLEAN 1`, 11 `HIGH HIGH`.
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- **Options** lists item flags as words after the hex value (option bits, IM 36K10C10 §3.5):
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`blk` 1 blocked, `off` 2 offline (station not communicating), `uoff` 4 **updated offline**
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(written by an application such as `itmval` while offline), `ack` 8 acknowledged, `ublk` 16
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**updated blocked** (written while blocked, e.g. with `-o`); 32/64 direct/delayed alarm.
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So writing a station item whose station is down adds `uoff` (0x…8a → 0x…8e); internal items
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(no station) never get it.
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## Read limits
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```
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itmval -g -n <Section>.<Tag> -a <n>
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```
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`<n>`: 1 deadband, 2 low, 3 high, 4 low-low, 5 high-high. The limit is returned in `Value`.
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Items with no limits configured return `ITM-E-WRONG_ATT, Wrong attribute number used`.
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## Write a value
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```
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itmval -p -n <Section>.<Tag> -v <value> [-s <status>] [-q <quality>]
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```
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- Read the item first and note its value, so it can be restored.
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- Booleans take `-v 0` / `-v 1`; the status follows automatically (4 / 5).
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- `-s` sets the status explicitly (e.g. `-s 9` NORMAL). Without it, a numeric write gives 9.
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- `-o` overwrites a blocked item; `-t [<date>] <time> [GMT|LST]` sets the timestamp
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(default local civil time); `-e` writes to event history only, not the current value.
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- Read it back to confirm.
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## Verified examples (CI-Eng-Sample)
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| Command | Result |
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|---|---|
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| `itmval -p -n CI-Eng-Sample.TANK1.INFLOW -v 120.5` | Value 120.5, status 9 |
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| `itmval -p -n CI-Eng-Sample.TANK1.INFLOW -v 130 -s 9` | Value 130, status 9 |
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| `itmval -p -n CI-Eng-Sample.PUMP1.RUNNING -v 1` | Value 1, status 5 (BOOLEAN 1) |
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| `itmval -g -n CI-Eng-Sample.TANK1.LEVEL -a 2` / `-a 3` / `-a 4` / `-a 5` | 20 / 80 / 10 / 90 |
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