Omron CJ1W-MAD42 — PLC Controller
SKU: CJ1W-MAD42USD 215.00
CJ-series mixed analog I/O unit with 4 differential inputs and 2 outputs, per-channel configurable ranges (-10 to +10 V, 0-5/10 V, 1-5 V, 4-20 mA). Resolution 1/4,000 default settable to 1/8,000; conversion 1 ms or 250 µs/point; input disconnection detection on 1-5 V / 4-20 mA ranges.
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Product Overview
The CJ1W-MAD42 is Omron's CJ-series mixed analog I/O unit, combining 4 differential analog inputs and 2 analog outputs in a single 31 mm wide slot. It is the workhorse unit for process-control loops on packaging machines, HVAC skids, water-treatment skids, and any application where the PLC reads a 4-20 mA signal from a transmitter (pressure, flow, temperature, level) and writes a 4-20 mA or 0-10 V output to a valve positioner, VFD speed reference, or damper actuator.
Resolution and conversion speed trade-off
The CJ1W-MAD42 has two resolution settings: 1/4,000 default (1 ms/point conversion speed) and 1/8,000 high-resolution (250 µs/point conversion speed). The 1/4,000 default provides 12-bit resolution (4,096 discrete values) over the full input range, sufficient for most process-control applications where the transmitter's intrinsic accuracy is ±0.1 to ±0.5% of full scale. The 1/8,000 high-resolution mode provides 13-bit resolution (8,192 discrete values) for applications requiring finer discrimination — typically strain-gauge load cells, precision pressure transducers, or pH / conductivity analyzers.
Input disconnection detection on 1-5 V / 4-20 mA ranges
The CJ1W-MAD42 supports per-input disconnection detection on the 1-5 V and 4-20 mA ranges — a critical safety feature for current-loop transmitter inputs. If the input voltage drops below 0.3 V (or the current drops below 1.2 mA), the unit interprets the loss as a wire break or sensor failure and sets a per-input disconnection flag in the allocated I/O memory. The PLC program reads this flag and raises an alarm (instead of treating the near-zero reading as a valid low process value, which could cause a control valve to slam shut on a stuck-low sensor).
Scaling engineering units
The CJ1W-MAD42's per-channel scaling lets the engineer define the engineering-unit range that maps to the analog input range. For example, for a 4-20 mA pressure transmitter with 0-100 PSI range: the engineer scales 4 mA = 0 (raw value 0) to 20 mA = 10000 (raw value 4,000), so the digital value in the PLC's DM area reads 0-10000 for 0-100 PSI. The scaling is independent per channel, so different inputs can have different unit ranges (temperature in °C, pressure in kPa, flow in L/min) without scaling gymnastics in the PLC program. The PLC program reads the scaled engineering-unit value directly.
Key Features
- CJ-series mixed analog I/O unit
- 4 differential analog inputs
- 2 analog outputs
- Input signal ranges: -10 to +10 V, 0 to 5 V, 0 to 10 V, 1 to 5.
- Output signal ranges: -10 to +10 V, 0 to 5 V, 0 to 10 V, 1 to 5.
- Resolution: 1/4,000 default, settable to 1/8,000
- Conversion speed: 1 ms/point default, settable to 250 µs/point
- Accuracy: ±0.2% of F.S., ±0.4% of F.S.
- SKU: CJ1W-MAD42
- Series: CJ1W Special I/O Units (CJ-series analog I/O)
- I/O: 4 I/O
Best-Fit Applications
- Pressure control loop on a boiler — 4-20 mA pressure transmitter on input 0, PID loop in CJ2M CPU, 4-20.
- Flow control loop on a water-treatment skid — 4-20 mA magnetic flow meter on input 1, PID loop with the.
- Tank level control on a chemical batching system — 4-20 mA hydrostatic level transmitter on input 2, 4-20 mA output.
- HVAC damper actuator control on a cleanroom — 0-10 V input from a room-pressure sensor on input 3, 0-10 V.
Buying Checklist
- Pick CJ1W-MAD42 for 4AI + 2AO mixed analog I/O — standard PID control loops, valves, VFD speed references, multi-variable process control
- Pick CJ1W-AD042 — for input-only applications, slightly lower cost
- Pick CJ1W-DA041 — for output-only applications, slightly lower cost
- Pick CJ1W-AD081-V1 — for higher-density input, higher resolution
- Pick CJ1W-PH@@@ for high-density analog — when you need 8+ channels in a single slot
- Pick CJ1W-TS@@@ / CJ1W-PT@@@ for thermocouple / RTD inputs — for direct temperature sensor inputs
Technical Specifications
| Model | CJ1W-MAD42 |
|---|---|
| Series | CJ1W Special I/O Units (CJ-series analog I/O) |
| Type | Mixed analog I/O unit (4 inputs + 2 outputs) |
| Analog Inputs | 4 differential inputs |
| Analog Outputs | 2 outputs |
| Input Signal Ranges | -10 to +10 V, 0 to 5 V, 0 to 10 V, 1 to 5 V, 4 to 20 mA (per-channel configurable) |
| Output Signal Ranges | -10 to +10 V, 0 to 5 V, 0 to 10 V, 1 to 5 V, 4 to 20 mA (per-channel configurable) |
| Resolution (default) | 1/4,000 (12-bit equivalent) |
| Resolution (high-resolution mode) | 1/8,000 (13-bit equivalent) |
| Accuracy (Voltage) | ±0.2% of F.S. (at 23 ± 2 °C, 55 ± 10 % RH) |
| Accuracy (Current) | ±0.4% of F.S. (at 23 ± 2 °C, 55 ± 10 % RH) |
| Input Impedance (Voltage) | 1 MΩ min |
| Input Impedance (Current) | 250 Ω |
| Voltage Output Max Current | 5 mA (max load 2 kΩ) |
| Current Output Max Load | 600 Ω (at 24 VDC supply, sourced through output transistor) |
Resources & Downloads
FAQ for CJ1W-MAD42
What's the difference between CJ1W-MAD42 and CJ1W-AD042 or CJ1W-DA041?
The CJ1W-MAD42 is a mixed analog I/O unit that combines 4 analog inputs and 2 analog outputs in one slot. The CJ1W-AD042 is an input-only unit with 4 analog inputs (no outputs, no output channel). The CJ1W-DA041 is an output-only unit with 2 analog outputs (no inputs). For applications with both inputs and outputs, the MAD42 saves DIN-rail space and cost compared to having both an AD042 and a DA041. For input-only applications, the AD042 is slightly cheaper.
How does the input disconnection detection work on the CJ1W-MAD42?
The CJ1W-MAD42 monitors each input on the 1-5 V and 4-20 mA ranges and detects when the input signal drops below the live-zero threshold (0.3 V for 1-5 V, 1.2 mA for 4-20 mA). When this happens, the unit sets a per-input disconnection flag in the allocated I/O memory (the PLC program reads this flag and raises an alarm).
Can I configure different input ranges on different channels of the CJ1W-MAD42?
Yes — each of the 4 inputs is independently configurable for any of the 5 supported ranges (-10 to +10 V, 0 to 5 V, 0 to 10 V, 1 to 5 V, 4 to 20 mA). Likewise, each of the 2 outputs is independently configurable. The configuration is done in the CJ CPU's I/O memory using the allocated I/O words for the unit.
What's the difference between 1/4,000 and 1/8,000 resolution modes?
The 1/4,000 default mode provides 4,000 discrete values across the full input range (e.g., 0-4000 for 0-10 V, or 0-4000 for 4-20 mA). This is equivalent to 12-bit resolution (4096 = 2^12). The 1/8,000 high-resolution mode provides 8,000 discrete values across the full input range, equivalent to 13-bit resolution (8192 = 2^13). The 1/8,000 mode discriminates finer signals (e.g., 0-10000 PSI would resolve to 1.25 PSI steps vs 2.5 PSI steps at 1/4,000).
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