TONR (Timer On-Delay Retentive)
Siemens retentive on-delay timer that accumulates time across multiple enable cycles.
The TONR (Timer On-Delay Retentive) is Siemens' implementation of a retentive on-delay timer, functionally equivalent to the RTO. It accumulates time while the input is TRUE and retains the accumulated value when the input goes FALSE. The output activates when accumulated time reaches the preset. A dedicated reset input is required to clear the timer. TONR is commonly used in Siemens S7-1200 and S7-1500 controllers for maintenance interval tracking and total run-time monitoring.
Parameters
Inputs
| Name | Type | Description |
|---|---|---|
| IN | BOOL | Timer enable input |
| PT | TIME | Preset time value |
| R | BOOL | Reset input - clears accumulated time |
Outputs
| Name | Type | Description |
|---|---|---|
| Q | BOOL | Timer done output |
| ET | TIME | Accumulated elapsed time |
Ladder Logic Example
// Ladder Logic - TONR (Siemens Retentive Timer) // // |----[ Pump_Running ]----[TONR Filter_Timer]----| // | IN: Pump_Running | // | PT: T#200h | // | R: Filter_Reset | // | Q: Filter_Change_Due |
Structured Text Example
VAR
Filter_Timer : TONR;
Pump_Running : BOOL;
Filter_Change_Due : BOOL;
Filter_Reset : BOOL;
END_VAR
Filter_Timer(IN := Pump_Running, PT := T#200h, R := Filter_Reset);
Filter_Change_Due := Filter_Timer.Q;20 Production-Ready Ladder Logic Templates
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Platform-Specific Implementation
Siemens (TIA Portal)
Native TONR instruction in TIA Portal for S7-1200/1500. Uses IEC_TIMER data type.
Allen-Bradley (Studio 5000)
Equivalent to RTO instruction. Use RES for reset.
CODESYS
Implement using TON with persistent variable or create custom FB.
Common Applications
- Filter change intervals
- Lubrication schedules
- Equipment run-hour tracking
- Preventive maintenance alerts
Common Mistakes to Avoid
- Using TONR on platforms that do not support it natively
- Forgetting the reset input after maintenance is performed
Frequently Asked Questions
What is TONR (Timer On-Delay Retentive) in PLC programming?
Siemens retentive on-delay timer that accumulates time across multiple enable cycles. The TONR (Timer On-Delay Retentive) is Siemens' implementation of a retentive on-delay timer, functionally equivalent to the RTO. It accumulates time while the input is TRUE and retains the accumulated value when the input goes FALSE.
What are common applications of TONR (Timer On-Delay Retentive)?
TONR (Timer On-Delay Retentive) is commonly used for: Filter change intervals, Lubrication schedules, Equipment run-hour tracking, Preventive maintenance alerts.
How do I use TONR (Timer On-Delay Retentive) in different PLC platforms?
Siemens: Native TONR instruction in TIA Portal for S7-1200/1500. Uses IEC_TIMER data type. Allen-Bradley: Equivalent to RTO instruction. Use RES for reset. CODESYS: Implement using TON with persistent variable or create custom FB.
Related Function Blocks
RTO (Retentive Timer On)
Timer retains accumulated value when input goes FALSE; requires manual reset.
View Reference →TON (Timer On-Delay)
Starts timing on rising edge, output activates after preset delay.
View Reference →TOF (Timer Off-Delay)
Output stays TRUE for preset time after input goes FALSE.
View Reference →TP (Timer Pulse)
Generates a fixed-duration pulse on rising edge of input.
View Reference →RTOR (Retentive Timer On with Reset)
Retentive on-delay timer with integrated reset input for accumulated time clearing.
View Reference →Stop Writing Ladder Logic From Scratch
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