PLC-5 Timers

Introduction to PLC-5 Timers There are three types of PLC-5 Timers that we will cover in this section: TON, TOF, and RTO. Generally, the TON (Timer On Delay) instruction delays the DN (Done) bit from going true. On the other hand, the TOF (Off Delay Timer) delays the DN bit Read More »

PLC-5 Timers

PLC-2 On Delay Timer

Introduction to the PLC-2 On Delay Timer. Despite being obsolete and out of date, I still love to program the PLC-2. In this post, we’ll discuss the PLC-2 On Delay Timer. We use the TON instruction to delay the DN bit from energizing. You will see this on conveyors, so Read More »


TON and TOF Differences

Introduction of TON and TOF Differences There are several TON and TOF Differences that you need to be aware of. In summary, the TON delays the DN bit from turning ON. The TOF Instruction delays the DN Bit from shutting off. The TON Instruction By far, the TON instruction is Read More »

TON and TOF Differences

Delaying outputs on and off

Introduction to delaying outputs on and off In this post, I’ll explain delaying outputs on and off can be used in the SLC500 processor. For example: We have a motor with a fan. When a main motor starts, a fan needs to start two seconds later. When the motor is Read More »

Delay Outputs on and off

Timers in the SLC-500

Introduction to timers in the SLC-500 Processor. Timers in the SLC-500 processor are very similar to timers in other AB Processors. There are 3 types of timers: On Delay (TON), Off Delay (TOF) and the Retentive Timer (RTO). The On Delay Timer (TON) delays the Done bit (DN) from turning Read More »

RTO Timer

SLC 500 On Delay Timer

Introduction to the SLC 500 On Delay Timer The SLC 500 On Delay Timer (TON instruction) can delay an event from taking place. When the run of logic goes true, the EN (Enable) bit goes true. The timer will then start timing (the TT bit goes true). After the accumulated Read More »


ControlLogix Timers 2

Introduction to ControlLogix Timers ControlLogix timers are used to delay events, or to time events.    There are three timers in the ControlLogix processor.  The TON (Timer On Delay) delays an event from turning on.   Next, the TOF (Timer Off Delay) Delays an event from shutting off.  Then we Read More »

TOF Timeout