Monarch ACT-1B Panel Tachometer

1/8 DIN panel tachometer for 5…99,999 RPM with universal sensor inputs, 5-digit red LED, and optional scalable analog or pulse outputs.

Key advantages

5…99,999 RPM with ±1 RPM or 0.005% of reading accuracy.
Universal inputs — optical, proximity, magnetic, infrared, laser, TTL, or 2…50 Vac peak-to-peak.
1/8 DIN — 5-digit 0.56 in. red LED; panel cutout 3.58 × 1.74 in.
Optional outputs — 4–20 mA (IO), 0–5 Vdc (AO), or TTL pulse (PO); USB + PM Remote Software for user configuration.

Typical applications

Panel or benchtop RPM display with Monarch “-W” tinned-wire speed sensors.
Machine speed indication into PLC/recorder via optional analog output.
Setups needing factory configuration or field USB programming.

Selection guide

Speed range — 5…99,999 RPM; resolution 1 RPM (programmable finer with USB/PM Remote).
Accuracy — ±1 RPM or 0.005% of reading.
Display — 5-digit, 0.56 in. [14 mm] red LED; update twice/sec above 120 RPM (programmable).
Power — Standard 100–240 Vac ±10%, 50/60 Hz; optional isolated 12 or 24 Vdc ±10%, 5 W.
Sensor excitation — 12 Vdc @ 20 mA (proximity) or 75 mA (other); optional 5 or 24 Vdc.
Inputs — Universal; standard 1 pulse/rev (programmable 1…999 with USB cable).
IO / AO / PO options — 4–20 mA (15-bit, 12 Vdc compliance); 0–5 Vdc; 0–5 V TTL pulse.
Environment — Indoor use per IEC61010-1; operating 0…50 °C; humidity to 80% RH (derates above 31 °C).
Sensors — ROS-W, ROS-HT-W-25, P5-11, M-190W / MT-190W, IRS-W, ROLS-W / RLS-W (recommended).
NIST — Optional NIST Traceable Certificate (order explicitly).

Common mistakes

Forgetting to specify AC vs DC power and the analog/pulse option at order time.
Pairing a sensor that needs different excitation than the configured supply.
Expecting push-button field programming without the USB programming cable + PM Remote Software.
Ordering ACT-1B when alarms/Ethernet of ACT-3X are actually required.
Test & measurement

When to RFQ / what to tell us

Power: 100–240 Vac vs 12/24 Vdc isolated.
Output options: none / 4–20 mA / 0–5 V / TTL pulse; full-scale RPM for analog.
Sensor type and excitation needs; pulses per revolution.
NIST certificate yes/no; USB cable yes/no.
Quantity and ship-to country.

Request a Quote · Get selection help

Specs

Spec	Value
SKU	23707
Brand	Monarch Instrument
Model	ACT-1B
Product type	panel tachometer
Measuring range	5 to 99,999 RPM
Accuracy	±1 RPM or 0.005% of reading
Display	5-digit, 0.56 in. (14 mm) red LED
Output signal	Optional 4–20 mA, 0–5 Vdc, or 0–5 V TTL pulse
Supply voltage	Standard 100–240 Vac ±10% 50/60 Hz; optional isolated 12 or 24 Vdc ±10%, 5 W
Process connection	1/8 DIN panel; cutout 3.58 × 1.74 in. (91 × 44 mm); depth 4.5 in. (114 mm)
Ambient temperature	0 to 50 °C (32 to 122 °F)
Notes	Compatible with Monarch “-W” sensors. USB programming cable + PM Remote Software required for user reconfiguration. Specs from monarchinstrument.com ACT-1B page.

Documents

ACT-1B product page (OEM)

FAQ

Q: Can I change pulses-per-rev in the field? A: Yes, with the optional USB programming cable and free PM Remote Software (also enables live PC/Excel data).

Q: Is NIST included? A: Optional — request the NIST Traceable Certificate explicitly when RFQing ACT-1B.

Q: What should I send for a quote? A: Power, output option + full-scale RPM, sensor/excitation, NIST yes/no, quantity, ship-to. Compatible with systems using Monarch ACT-1B if you need a drop-in check — we do not claim authorized-dealer status.