Industrial timer controller (time relay and digital time switch)

01

Choose the timing function and range

Shenler describes timer relay functions: on-delay (the load switches on a set time after the relay is energised), off-delay (the load switches off a set time after the relay is de-energised), interval (alternating on and off periods), one-shot (the load runs for a set time after energising, regardless of how long the input lasts) and cycle (repeating set on and off periods). It lists timer relays for 24–230 V AC/DC with timing ranges from 0.1 s to 30 min and a timing IC giving ±2% accuracy, with a choice of mounting options. [1]

Editorial calculation: ±2% is ±0.2 s on a 10 s setting and ±36 s on a 30 min setting; if a process needs tighter timing at long settings, ask for a timer with a finer range or better accuracy. [1]

OMRON's H3DT family shows how one DIN-rail timer series splits by function. All models are analog, 17.5 mm wide, DIN-rail mounted with push-in terminals and relay output, and the family lists 18 operating modes, among them ON delay (power-on or signal start), OFF delay (signal), interval, flicker ON or OFF start, one-shot output, cumulative ON delay and interval, and instantaneous operation. The multifunction, extended-multifunction and on-delay models cover 0.1 s to 1,200 h with 1 or 2 SPDT contacts at 5 A on 24–240 VAC/DC; the twin and star-delta models list 1–120 s, and the power-OFF-delay models 0.1–12 s or 1–120 s on 24–48 VAC/DC. [3]

Editorial calculation: 1,200 h is 4,320,000 s, so a 0.1 s to 1,200 h timer spans a 43,200,000 : 1 range across its range switch; ask which sub-range your setting falls in, because dial accuracy is stated against the selected range. [3]

Editorial note: draw the timing diagram the circuit needs (input, output, delay) and send it with the request, since function names vary between makers.

Give the supplier the timing function (on-delay, off-delay, interval, one-shot, cycle, schedule), time range and setting resolution, accuracy, supply voltage (AC/DC), contact type and rating with load type, number of outputs, mounting (DIN rail, socket, panel), display and programming method, power reserve, operating temperature, and certifications.

02

Match supply, load and power reserve

VIOX describes a digital timer switch as opening or closing an output according to stored daily, weekly, pulse, cycle or other programs to automate lighting, pumps, ventilation and process auxiliaries, and says selection depends on supply voltage, contact and load duty, number of outputs, shortest switching interval, program capacity, power reserve, mounting and whether an interposing contactor is needed. Its published models include DIN-rail, panel and screw-mounted switches for 12/24/48 V AC/DC or 110–240 V AC, contacts of 16 A resistive (8 A inductive) up to 25–30 A, 8 to 18 on/off programs, and battery backup described as up to or more than 60 days of reserve, or a 5-year lithium battery. [2]

Editorial note: a 16 A resistive contact rated 8 A inductive should not switch a motor or other inductive load at 16 A; size the timer's contact for the load type or use it to drive a contactor, as VIOX's selection notes suggest. [2]

03

Check contact life, DC breaking capacity and repeatability

Finder's 80 Series data sheet (IX-2025) gives full figures for 17.5 mm modular timers on 35 mm rail. The single-function 80.11 (on-delay), 80.21 (interval) and 80.41 (off-delay with control signal) have six time scales from 0.1 s to 24 h — 0.1–2 s, 1–20 s, 0.1–2 min, 1–20 min, 0.1–2 h and 1–24 h — and a 1 CO (SPDT) AgNi contact rated 16 A (30 A peak) at 250 V AC, 4,000 VA AC1, 750 VA AC15 at 230 V, 0.55 kW for a single-phase motor, and DC1 breaking of 16 A at 24 V, 0.3 A at 110 V and 0.12 A at 220 V, with a 500 mW (10 V/5 mA) minimum load. Supply is 24–240 V AC/DC (16.8–265 V operating) at under 1.8 VA or 1 W. Repeatability is ±1%, setting accuracy over the full range ±5%, recovery time 100 ms, minimum control impulse 50 ms (80.41), electrical life 50,000 cycles at rated AC1 load, ambient −20 to +60 °C and protection IP20. The multi-function 80.71 with a 1 A solid-state output lists an electrical life of 100 million cycles at −20 to +50 °C. [4]

Editorial calculation: 50,000 cycles at one switching a minute lasts about 830 hours (35 days), while 100 million solid-state cycles at the same rate last about 190 years, so frequent cycling of a small load favours a solid-state output; the 16 A contact breaks only 0.3 A at 110 V DC, so DC loads need checking separately. The ±5% setting accuracy is on the dial and the ±1% repeatability on the result, so set the timer against a stopwatch once installed. [4] [1]

04

Compare what suppliers offer

Suppliers linked to this page list timer relays or time switches; each card links to the page reviewed.

The suppliers reviewed list timer relays and time switches with other relays and low-voltage controls; ask each for timing functions and ranges, accuracy and repeat accuracy, contact ratings by load type, power reserve, mounting and certifications.

05

Trace the timer parts

This is a functional reference built from the sources cited; it is not one maker's design.

06

Fill the specification fields with values for your circuit

A timer quotation needs values for your circuit. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.

07

Send the function, load and supply data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Function: [timing diagram; mode]
Range: [min; max; resolution]
Accuracy: [required]
Supply: [voltage AC/DC]
Load: [type; current; contactor]
Outputs: [number; contact type]
Backup: [power reserve]
Mounting: [DIN rail; panel]

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