The 23 ladder instructions of the LADX ladder editor, which the LADV controllers execute.
| Document | Ladder instruction reference |
| Code | LADV-IR-LD |
| Revision | 1.0, 1 November 2026 |
| Firmware | V1.0.0 |
| Issued by | Wartens, makers of LADX |
How a rung is solved
A rung is solved left to right. Conditions on one branch are in series, so all must pass; branches are in parallel, so any one passes. The result, the rung's power, drives every output on the right in order. Rungs are solved top to bottom once per scan, and a JSR runs another routine where it stands before the next rung. Timers and counters keep their state in their own tag, with .DN, .TT and .EN bits and accumulated and preset values. Edges are per instruction: a CTU counts once when its rung goes true, however many scans it stays true.
Bit
| Mnemonic | Name | Where | Behaviour |
|---|
| XIC | Examine On | Condition | Passes power when the bit is 1. A normally-open contact. |
| XIO | Examine Off | Condition | Passes power when the bit is 0. A normally-closed contact. |
| ONS | One Shot | Condition | Passes power for a single scan on the rising edge. |
| OTE | Coil | Output | Follows the rung: 1 while powered, 0 when not. |
| OTL | Latch | Output | Sets the bit to 1 and leaves it there. |
| OTU | Unlatch | Output | Resets the bit to 0. |
Timer/Counter
| Mnemonic | Name | Where | Behaviour |
|---|
| TON | Timer On | Output | Times while powered. DN goes true at the preset. |
| TOF | Timer Off | Output | DN is true while powered, and stays true for the preset after power is lost. |
| CTU | Count Up | Output | Counts one on each rising edge. DN at the preset. |
| CTD | Count Down | Output | Counts down one on each rising edge. |
| RES | Reset | Output | Clears a timer or counter's accumulator. |
Compare
| Mnemonic | Name | Where | Behaviour |
|---|
| EQU | Equal | Condition | Passes power when the two values are equal. |
| NEQ | Not Equal | Condition | Passes power when the two values differ. |
| GRT | Greater | Condition | Passes power when the first value is greater. |
| LES | Less | Condition | Passes power when the first value is less. |
| GEQ | Greater or Equal | Condition | Passes power when the first is greater or equal. |
| LEQ | Less or Equal | Condition | Passes power when the first is less or equal. |
Program
| Mnemonic | Name | Where | Behaviour |
|---|
| JSR | Call routine | Output | Runs another routine and comes back. The tag is the routine's name. |
Move/Math
| Mnemonic | Name | Where | Behaviour |
|---|
| MOV | Move | Output | Copies a value into another tag. |
| ADD | Add | Output | Adds two values into a destination. |
| SUB | Subtract | Output | Subtracts the second value from the first. |
| MUL | Multiply | Output | Multiplies the two values into a destination. |
| DIV | Divide | Output | Divides the first value by the second. Dividing by zero is reported rather than written. |
