Nothing close enough? Start from a blank ladder logic → Describe it in one paragraph.
How to use a ladder logic template.
- 01Map your machine stations
List each station (fill nozzle, seal jaw, cutter, checkweigher, labeller, reject gate) with its actuator type — pneumatic cylinder, servo, or solenoid — and its associated sensor feedback.
- 02Define the cycle trigger
Specify what starts each machine cycle — a product-present sensor, a main shaft encoder pulse, or an operator foot switch. ChatDiagram uses this as the rung enable for the first step.
- 03Set timers for seal and dwell
Enter seal jaw dwell time, fill valve open time, and any settle delays. ChatDiagram places TON instructions with the correct presets on each actuator output rung.
- 04Add reject and counter logic
Describe your reject criterion (weight out of tolerance, vision fail, metal detector trip) and the reject gate delay. ChatDiagram adds a shift-register or TOF-delay reject rung and a CTU production counter.
- 05Export for commissioning
Download the ladder diagram as PDF to accompany your commissioning protocol and hand to the OEM or site electrician.
Questions about ladder logic templates
How is a reject gate triggered by a checkweigher in ladder logic?
The checkweigher outputs a REJECT signal (digital bit) when a product is out of tolerance. Because the product travels a fixed distance on the conveyor before reaching the reject gate, a shift register or a TOF (Timer Off-Delay) delays the gate actuation by the transit time. The gate solenoid fires only when the reject bit is live and the delay has elapsed, diverting exactly the flagged product.
How do I implement a production counter in ladder logic?
Use a CTU (Count Up) instruction. The count input rung examines a one-shot (OSR) contact on the good-product sensor so the counter increments once per pack rather than every scan cycle. The preset can be set to a shift target; the DN bit triggers a 'target reached' output or HMI alarm. A reset push-button on the HMI energises the CTR rung to zero the count at shift start.
What is the safest way to handle a seal-jaw fault during a packaging cycle?
A thermal overload on the seal bar heater or a jaw-position sensor mismatch should trigger an immediate Category 0 or Category 1 stop depending on your SIL assessment. In ladder logic, wire the fault as an NC series contact directly on the jaw actuator output rung, and add a latched FAULT coil that requires a manual key-switch reset after the operator has cleared the jam.
Can packaging machine ladder logic handle recipe-based changeovers?
Yes — store recipe parameters (fill volume preset, seal dwell, indexer position) in data registers. An HMI recipe selector writes the active recipe's register values before the run cycle starts. Timer presets and counter targets reference these data registers rather than fixed values, so a single ladder program can run multiple product formats.
How do I synchronise a fill nozzle with an indexer in ladder logic?
The indexer positions the container under the nozzle and outputs an AT_POSITION bit when settled. The fill rung examines AT_POSITION in series with the cycle-enable bit, opens the fill valve, and starts a TON fill timer. When the timer DN bit fires, the valve closes and a FILL_DONE bit advances the indexer to the next position.