H3CR-A8 Wiring Guide: Omron Multifunction Timer Modes and Setup
On this page
Overview
A filling line starts overfilling the first carton of every batch: the dosing pump holds two seconds past its dwell time, the operator adjusts the HMI with no effect, and maintenance finds a plug-in timer behind the panel door, its mode switch set by hands that left the plant years ago. Fifteen minutes of front switch work later, the line runs right again. That plug-in timer is the subject of this page.
The H3CR-A8 is the Omron multifunction digital timer in the 8-pin plug-in format. Several operating modes are selected with front panel switches, on-delay being the most common, and a time range selector sets the span the main setting dial covers. This listing is the 24-48 VAC / 12-48 VDC supply variant, which covers control panels that run DC or low-voltage AC supplies. The exact mode list and timing ranges for your version are in the Omron H3CR datasheet, and the datasheet should settle any question about a mode before you wire to it.
The H3CR line has been in service for decades, so it appears in packaging machines, hoists, pump panels, kilns, and process skids across nearly every industry. Panels that old accumulate undocumented changes, and the timer's front switches are the first place those changes hide. Start there before you order parts.
Quick answer
The H3CR-A8 is an Omron multifunction plug-in timer, 8-pin, for panels with a 24-48 VAC or 12-48 VDC supply. Wrong timing on an installed unit is nearly always the front mode or range switch, so set those first and check the socket supply before replacing the timer. When buying, match three things: pin count against the socket, supply range against the panel, and the operating modes you use against the datasheet for that version.
H3CR-A8 and H3CR-A compared
The H3CR-A8 and the H3CR-A share the same housing family and the same front layout, and they differ in the plug-in base and the operating mode set. The distinction is easy to get wrong at the ordering desk because the two numbers sit one character apart.
| Attribute | H3CR-A8 | H3CR-A |
|---|---|---|
| Pins | 8-pin plug-in | 11-pin plug-in |
| Socket | 8-pin round socket | 11-pin round socket |
| Operating modes | A subset of the H3CR modes, including on-delay (full list: see datasheet) | The full mode set, including the wye-delta starting and dual-program modes that need the extra pins (see datasheet) |
| Front controls | Mode selector, time range selector, setting dial | Same layout, more mode positions |
| Supply variants | This listing: 24-48 VAC / 12-48 VDC | Multiple AC and AC/DC variants (see datasheet) |
| Typical use | Dwell, delay, and cycle timing in existing panels | Applications that use wye-delta starting or dual-program timing |
Choose by the socket first and the modes second. An 8-pin unit cannot seat in an 11-pin base or the other way around, and the mode set decides whether the timer can do the job at all. If you are specifying a new panel instead of maintaining an old one, confirm both points in the H3CR datasheet before you order.
Setting the mode and time range
The front of the timer carries a mode selector, a time range selector, and the main setting dial. The mode selector picks the operating behavior, and the range selector sets which span the dial covers. Set the mode and range first, then the dial, then cycle power and time the output against a stopwatch before you release the machine.
Two habits prevent most timer callbacks. First, write the mode and range settings on the panel drawing or on a card inside the door, because a bare dial position means nothing to the next technician. Second, after any change, power the timer down and up again, then watch one full cycle: settings take effect on the next power-up, and an unproven change hides until the machine stops at the wrong moment.
The exact mode list, timing ranges, and contact arrangements for your variant are in the Omron H3CR datasheet. Do not pick a mode from its letter alone, because the same letter can map to different behaviors across timer families and even across versions of the same family.
Run the machine through a few repetitions after any setting change. A timer that looks correct on one cycle can still disagree with the machine on the next, especially in repeat-cycle modes where the output state at power-up matters. Watch the load itself, because the timer face only tells you what the relay believes is happening.
Socket wiring and supply
Warning: Disconnect power and follow your lockout and tagout procedure before pulling the timer from its socket or touching the wiring. The socket carries the full supply voltage on live pins whenever the panel is energized.
The timer plugs into a round 8-pin socket. Supply lands on the pins the datasheet marks for the supply, sized for 24-48 VAC or 12-48 VDC on this variant, and the control functions such as start and reset sit on the remaining pins. Take the pinout from the datasheet or the socket label rather than from memory, because a timer that worked in one panel may have been wired differently in the next one.
Measure the socket supply before you blame the timer. A supply outside the 24-48 VAC / 12-48 VDC window, or DC on pins that expect AC, produces symptoms that look exactly like a failed unit. When the timer itself is the fault, pull it from the socket with power off and drop in the replacement: the plug-in format is the whole point of the design, and a 30-second swap beats panel rewiring when a timer fails at 2 a.m.
Common issues and troubleshooting
Most H3CR faults trace to settings or supply before they trace to a failed unit. Work the table from the top.
| Symptom | Likely cause | Fix |
|---|---|---|
| Timer never starts counting | No supply at the socket, or supply outside the variant range | Measure the supply at the socket pins and check the variant marking on the timer housing |
| Timing is wrong but stable | Mode or range selector set differently from the panel documentation | Set mode and range per the datasheet and the panel drawing, power cycle, re-time against a stopwatch |
| Output relay never switches | Load circuit fault, or contact wear after years of switching | Measure the contact across the socket pins with the timer commanded on, then check the load side |
| Output cycles on and off repeatedly | Mode selector on a repeat-cycle setting when the machine expects on-delay | Move the mode selector to the position the drawing calls for and power cycle |
| Timer resets mid-cycle | Reset or control terminal floating, or noise on a long control run | Check the control wiring against the datasheet pinout, shorten or shield the control run |
FAQ
Can I swap the H3CR-A8 for an H3CR-A?
Only if you also change the socket. The 8-pin and 11-pin versions use different bases and carry different mode sets, so a unit of one pin count will not seat in the other's base. Keep the pin count unless you are redoing the panel wiring anyway.
What supply does this variant take?
This listing is the 24-48 VAC / 12-48 VDC variant. Supply outside that window causes erratic operation or no operation, so measure the socket before you order. Other voltage variants exist in the H3CR family for panels at different supplies.
Where do I find the operating modes?
In the Omron H3CR datasheet for your exact version. The mode set differs between the 8-pin and 11-pin formats, and the datasheet lists each mode with its timing diagram and terminal use.
Need an H3CR-A8?
koeed.com stocks the Omron H3CR-A8 timer with worldwide shipping, a 12-month warranty, and RFQ pricing for volume orders. Buy H3CR-A8 at koeed.com
Need a quote for this part?
Send us the part number or article link — we will confirm price, availability and lead time.