REX-C Series PID Temperature Controller: Input Codes, Output Codes and Panel Data

The REX-C series is the classic universal-input PID temperature controller found on ovens, kilns, extruders and laboratory heaters worldwide. This page collects the data most often needed when specifying or replacing one. Ordering information is on the REX series product page, and terminal diagrams are in the REX wiring guide.

1. Models, panel and cutout sizes

Parameter	Specification
REX-C100	48 × 48mm panel, 45×45mm cutout
REX-C400	48 × 96mm panel, 45×92mm cutout
REX-C410	96 × 48mm panel, 92×45mm cutout
REX-C700	72 × 72mm panel, 68×68mm cutout
REX-C900	96 × 96mm panel, 92×92mm cutout
Depth	100mm body + 10mm bezel

2. Electrical specification

Parameter	Specification
Control method	ON/OFF, position PID and continuous PID; reverse-acting (F) or direct-acting (D)
Input	Thermocouple, Pt100, Cu50, 0–5V, 1–5V and mA signals
Input codes	K (K01–K07, K13–K14), J (J01–J06), R/S/B, E/N/T, Pt100 (D01–D10), Cu50 (P01–P10), 0–5V 401, 1–5V 601, 0–20mA 701, 4–20mA 801
Control output	M relay 250VAC 3A; V SSR drive 0–12VDC; 8 current 0–10mA or 4–20mA; T hybrid SCR trigger; analog 0–5V / 1–5V
Alarm output	Up to 2 alarms; N none, or A–L deviation, band and absolute modes
Accuracy	±0.5% FS
Sampling period	0.5s
PID range	P 0 to full range; I and D 0–3600s; control period 1–100s
Supply	AC supply, consumption <10VA
Operating environment	0 to 50°C, 30–85% RH

3. Input and range codes explained

A REX-C input code is a letter for the sensor family plus a two-digit range number. K02, for example, is a K-type thermocouple on a specific span. Two rules matter in practice:

• The range code sets the displayed span and the resolution. A wide range loses the decimal place; a narrow range keeps it.
• Current-input codes (0–20mA 701, 4–20mA 801) may need an external 250Ω shunt resistor across the input terminals — confirm at ordering.
• Pt100 uses D-series codes and Cu50 uses P-series codes; the two are not interchangeable and will read badly wrong if swapped.

4. Output codes and load matching

Parameter	Specification
M — relay	250VAC 3A contact. Switch a contactor coil, not the heater, above roughly 1000 W.
V — SSR drive	0–12VDC pulse. Matches the 3–32VDC input of the SSR-DA series.
8 — current output	0–10mA or 4–20mA for modulating valves and SCR power regulators.
T — SCR trigger	Hybrid trigger output for thyristor power stages.

5. Commissioning checklist

• Verify the sensor code before energising the heaters; a Pt100 probe read as a thermocouple can look plausible cold.
• Confirm F (reverse acting) for heating applications.
• Set the control period: 1–2s for SSR output, 20s or longer for a contactor.
• Run auto-tune at the working setpoint with the real load, then record P, I and D for future spares.
• Fit an independent over-temperature thermostat on any process where a runaway is hazardous — the controller alarm relay is indication, not protection.

6. FAQ

Which model replaces a failed REX-C100?

Any REX-C100 with the same input, output and alarm codes drops straight in — the 45×45mm cutout and terminal layout are unchanged.

Can I convert relay output to SSR output?

No. The output stage is hardware, selected by the M or V code at ordering.

What control period should I use with an SSR?

1 to 2 seconds. Short periods are exactly why an SSR is fitted; the same setting would destroy a contactor.

Where are the terminal diagrams?

In the REX-C100, C700 and C400/C900 wiring guide, covering both contactor and SSR methods.

Model code checks and quotations: sales@strong-ele.com.