Supported registers

This table lists the device families accepted by the current parser and explains how the high-level helper layer treats them.

Bit device families

Family	Unit	Numbering	Notes
`SM`	Bit	Decimal	Special relay.
`X`	Bit	Profile-dependent	Octal text for `melsec:iq-f`; hexadecimal text for every other profile.
`Y`	Bit	Profile-dependent	Octal text for `melsec:iq-f`; hexadecimal text for every other profile.
`M`	Bit	Decimal	Internal relay.
`L`	Bit	Decimal	Latch relay.
`F`	Bit	Decimal	Annunciator.
`V`	Bit	Decimal	Edge relay.
`B`	Bit	Hexadecimal	Link relay.
`TS`	Bit	Decimal	Timer contact.
`TC`	Bit	Decimal	Timer coil.
`LTS`	Bit	Decimal	Long timer contact.
`LTC`	Bit	Decimal	Long timer coil.
`STS`	Bit	Decimal	Retentive timer contact.
`STC`	Bit	Decimal	Retentive timer coil.
`LSTS`	Bit	Decimal	Long retentive timer contact.
`LSTC`	Bit	Decimal	Long retentive timer coil.
`CS`	Bit	Decimal	Counter contact.
`CC`	Bit	Decimal	Counter coil.
`LCS`	Bit	Decimal	Long counter contact.
`LCC`	Bit	Decimal	Long counter coil.
`SB`	Bit	Hexadecimal	Link special relay.
`DX`	Bit	Hexadecimal	Direct input; not valid for `melsec:iq-f`.
`DY`	Bit	Hexadecimal	Direct output; not valid for `melsec:iq-f`.

Family	Unit	Numbering	Notes
`SD`	Word	Decimal	Special register.
`D`	Word	Decimal	Data register and recommended first read family.
`W`	Word	Hexadecimal	Link register.
`TN`	Word	Decimal	Timer current value.
`LTN`	Word	Decimal	Long timer current value; use 32-bit `:D` or `:L` intent.
`STN`	Word	Decimal	Retentive timer current value.
`LSTN`	Word	Decimal	Long retentive timer current value; use 32-bit `:D` or `:L` intent.
`CN`	Word	Decimal	Counter current value.
`LCN`	Word	Decimal	Long counter current value; use 32-bit `:D` or `:L` intent.
`SW`	Word	Hexadecimal	Link special register.
`Z`	Word	Decimal	Index register.
`LZ`	Word	Decimal	Long index register; use 32-bit `:D` or `:L` intent.
`R`	Word	Decimal	File register.
`ZR`	Word	Decimal	Extended file register; the device-range catalog reports it unsupported for `melsec:iq-f`.
`RD`	Word	Decimal	Refresh data register; the device-range catalog reports it unsupported for `melsec:iq-f`, `melsec:qcpu`, `melsec:lcpu`, `melsec:qnu`, and `melsec:qnudv`.
`G`	Word	Decimal	Module buffer family; use raw or extended-device API only.
`HG`	Word	Decimal	Extended module buffer family; use raw or extended-device API only.

Suffix	Example	Meaning	Words
Plain	`D100`	Unsigned 16-bit value for normal word devices	1
`:U`	`D100:U`	Unsigned 16-bit value	1
`:S`	`D100:S`	Signed 16-bit value	1
`:D`	`D200:D`	Unsigned 32-bit value	2
`:L`	`D202:L`	Signed 32-bit value	2
`:F`	`D204:F`	IEEE-754 float32 value	2
`.n`	`D50.3`	One bit inside a word device	1 word read-modify-write

Topic	Rule
Long current families	`LTN`, `LSTN`, `LCN`, and `LZ` are 32-bit families. Do not request 16-bit word views; use `:D` or `:L`.
iQ-F direct devices	`DX` and `DY` are not valid for `melsec:iq-f`.
Module buffers	`G` and `HG` are raw or extended-device API families, not public high-level helper families.
`X`/`Y` numbering	`melsec:iq-f` uses octal text for `X` and `Y`; every other profile uses hexadecimal text.
PLC profile selection	Use canonical values such as `melsec:iq-r`; short aliases are rejected.
Profile detection	The library does not infer the active profile from `ReadTypeName` or model codes.
Device range catalog	Device-range catalog reads follow the fixed range profile derived from `plc_profile`.
First smoke test	Start with a simple `D` word read such as `D100`.
Bit-in-word notation	`.n` is valid only on word devices and uses one hexadecimal bit index from `0` to `F`.

See PROFILES.md for canonical profiles and profile-specific cautions.