SLMP Node-RED API Reference

This page is a user-facing index of the JavaScript SLMP client surface used by the Node-RED nodes. Use the usage guide for flow examples, and this page when you need to find the low-level operation name for a specific SLMP command family.

The main low-level client type is SlmpClient from lib/slmp/client.js.

Direct And Random Device Operations

Operation	Public API
Direct device read/write	`readDevices`, `writeDevices`
Random read	`readRandom`
Extended random read	`readRandomExt`
Random word/dword write	`writeRandomWords`
Extended random word/dword write	`writeRandomWordsExt`
Random bit write	`writeRandomBits`
Extended random bit write	`writeRandomBitsExt`
Block read/write	`readBlock`, `writeBlock`
Type name	`readTypeName`

Extended random APIs use the 008x subcommands. Use qualified device notation such as U1\G0, U3E0\HG0, or J2\SW10 where the route requires it.

The current Node-RED low-level client does not expose separate extended direct device helpers. Use the extended random APIs for routed random access.

Specialized Operations

Operation	Public API
Memory command words	`memoryReadWords`, `memoryWriteWords`
Extend-unit command bytes	`extendUnitReadBytes`, `extendUnitWriteBytes`
Extend-unit command words	`extendUnitReadWords`, `extendUnitWriteWords`
Label array access	`readArrayLabels`, `writeArrayLabels`
Label random access	`readRandomLabels`, `writeRandomLabels`
Remote CPU control	`remoteRun`, `remoteStop`, `remotePause`, `remoteLatchClear`, `remoteReset`
Remote password	`remotePasswordUnlock`, `remotePasswordLock`
CPU operation state	`readCpuOperationState`

Monitor registration/cycle APIs are not part of the current Node-RED low-level client surface.

High-Level Helpers

Operation	Public API
Address parsing and formatting	`parseDevice`, `deviceToString`, `normalizeAddress`, `parseAddress`, `formatParsedAddress`
Extended-device helpers	`normalizeExtensionSpec`, `resolveExtendedDeviceAndExtension`, `encodeExtendedDeviceSpec`
Typed values	`readTyped`, `writeTyped`
Named mixed snapshots	`compileReadPlan`, `readNamed`, `writeNamed`
Bit-in-word write	`writeBitInWord`

Target Module I/O Constants

ModuleIONo provides named request-header module I/O numbers for multi-CPU and routed CPU targets. Use these values in the route object's moduleIO field; omitted route targets still use the own-station route 0x03FF.

Constant	Value
`ModuleIONo.CONTROL_SYSTEM_CPU`	`0x03D0`
`ModuleIONo.STANDBY_SYSTEM_CPU`	`0x03D1`
`ModuleIONo.SYSTEM_A_CPU`	`0x03D2`
`ModuleIONo.SYSTEM_B_CPU`	`0x03D3`
`ModuleIONo.MULTIPLE_CPU_1` .. `ModuleIONo.MULTIPLE_CPU_4`	`0x03E0` .. `0x03E3`
`ModuleIONo.REMOTE_HEAD_1` / `ModuleIONo.REMOTE_HEAD_2`	`0x03E0` / `0x03E1`
`ModuleIONo.CONTROL_SYSTEM_REMOTE_HEAD` / `ModuleIONo.STANDBY_SYSTEM_REMOTE_HEAD`	`0x03D0` / `0x03D1`
`ModuleIONo.OWN_STATION`	`0x03FF`