SLMP Protocol for Python

High-level SLMP helpers for Mitsubishi PLC communication over Binary 3E and 4E frames.

This repository treats the high-level helper layer as the recommended user surface:

• SlmpConnectionOptions
• open_and_connect / open_and_connect_sync
• AsyncSlmpClient
• QueuedAsyncSlmpClient
• SlmpClient
• normalize_address
• read_typed / write_typed
• read_words_single_request / read_dwords_single_request
• read_words_chunked / read_dwords_chunked
• write_bit_in_word
• read_named / write_named
• poll

Installation

pip install slmp-connect-python

The latest release lives at https://pypi.org/project/slmp-connect-python/, where wheel and tarball downloads and metadata are available.

Quick Start

Recommended async path:

import asyncio

from slmp import SlmpConnectionOptions, open_and_connect, read_named, write_typed


async def main() -> None:
    options = SlmpConnectionOptions(
        host="192.168.250.100",
        plc_family="iq-f",
        port=1025,
    )
    async with await open_and_connect(options) as client:
        before = await read_named(client, ["D100", "D200:F", "D50.3"])
        print("before:", before)

        await write_typed(client, "D100", "U", 42)

        after = await read_named(client, ["D100", "D200:F", "D50.3"])
        print("after:", after)


asyncio.run(main())

Choose canonical plc_family explicitly. In the recommended high-level helper layer, the only PLC selector is plc_family.

High-Level PLC Selection

For normal application code:

• set plc_family
• let the library derive the fixed frame type, access profile, X / Y text rule, and device-range family
• do not pass raw frame_type, plc_series, or device_family

plc_family	Derived frame_type	Derived access_profile	X / Y text	Derived range family	Notes
iq-f	3e	ql	octal	iq-f	live-validated
iq-r	4e	iqr	hexadecimal	iq-r	live-validated
iq-l	4e	iqr	hexadecimal	iq-r	live-validated on L16HCPU
mx-f	4e	iqr	hexadecimal	mx-f	provisional; review in TODO.md
mx-r	4e	iqr	hexadecimal	mx-r	provisional; review in TODO.md
qcpu	3e	ql	hexadecimal	qcpu	retained path
lcpu	3e	ql	hexadecimal	lcpu	retained path
qnu	3e	ql	hexadecimal	qnu	retained path
qnudv	3e	ql	hexadecimal	qnudv	retained path

Low-level compatibility tools may still work with raw frame_type / plc_series, but that is not the normal public helper path.

High-level accepted plc_family values:

Canonical	Typical target	Notes
iq-f	FX5 / iQ-F	X / Y use manual octal text
iq-r	iQ-R	X / Y use hexadecimal text
iq-l	iQ-L	mapped to the iq-r range rules; live-validated on L16HCPU
mx-f	MX-F	pending live validation
mx-r	MX-R	pending live validation
qcpu	QCPU	3e/ql fixed profile
lcpu	LCPU	3e/ql fixed profile
qnu	QnU	3e/ql fixed profile
qnudv	QnUDV	3e/ql fixed profile

Practical rules:

• non-iQ-F X / Y: text such as X20 / Y20 is interpreted as hexadecimal
• iQ-F / FX5 X / Y: text such as X100 / Y100 is interpreted as manual octal notation and encoded to the binary numeric value
• example: X100 on iQ-F becomes binary device number 0x40
• if you pass a numeric DeviceRef, string notation is already resolved, so plc_family is not needed for that one address
• short aliases such as iqf, iqr, q, l, and qnudvcpu are rejected

Supported PLC Registers

Start with these public high-level families first:

• word devices: D, SD, R, ZR, TN, CN
• bit devices: M, X, Y, SM, B
• typed forms: D200:F, D300:L, D100:S
• mixed snapshot forms: D50.3, D100, D200:F
• current-value long families: LTN, LSTN, LCN

See the full public table in Supported PLC Registers.

Public Documentation

• Getting Started
• Supported PLC Registers
• Latest Communication Verification
• User Guide
• Samples
• Error Codes

Maintainer-only notes and retained evidence live under internal_docs/.

High-Level API Guide

Address Normalization

from slmp import normalize_address

print(normalize_address("x20"))   # X20
print(normalize_address("d200"))  # D200
print(normalize_address("x100", plc_family="iq-f"))  # X100

Single Typed Values

from slmp import read_typed, write_typed

temperature = await read_typed(client, "D200", "F")
counter = await read_typed(client, "D300", "L")
await write_typed(client, "D100", "U", 1234)

Use .bit notation only with word devices such as D50.3. Address bit devices directly as M1000, M1001, X20, or Y20. For communication, X / Y string addresses require explicit plc_family.

Device Range Catalog

Use plc_family and read the derived family SD block once.

from slmp import SlmpClient

with SlmpClient("192.168.250.100", 1025, plc_family="qnu") as client:
    catalog = client.read_device_range_catalog()
    for entry in catalog.entries:
        print(entry.device, entry.point_count, entry.address_range)

This path does not call read_type_name(). The client uses the fixed range family derived from plc_family.

Development

run_ci.bat
build_docs.bat
release_check.bat

License

Distributed under the MIT License.