5069-IY4: Wiring, Configuration, Temperature Reading, and Diagnostics
The 5069-IY4 is a 4-channel universal analog input module for the Allen-Bradley Compact 5000 I/O platform. Each channel can be independently configured for current (0–20mA, 4–20mA), voltage (0–5V, 0–10V, ±10V), RTD (PT385, PT3916, CU427, NI672, NI618 in multiple resistances), or thermocouple (Types B, C, D, E, J, K, N, R, S, T, TXK/XK(L)). This makes it the most versatile analog input module in the CompactLogix 5380 ecosystem — a single module can read a thermocouple on one channel, an RTD on the next, and a 4–20mA transmitter on a third. The module reports data as REAL (IEEE 754, 32-bit floating point) in engineering units, including direct temperature readout in Celsius, Fahrenheit, Kelvin, or Rankine for RTD and thermocouple inputs. This guide covers hardware installation, wiring for all four input types, cold junction compensation, Studio 5000 channel configuration, ladder logic examples, and diagnostic troubleshooting.
Contents
1. Module Overview
The 5069-IY4 belongs to Rockwell Automation's Compact 5000 I/O family, designed for the CompactLogix 5380, Compact GuardLogix 5380, CompactLogix 5480, and Compact 5000 EtherNet/IP adapter systems. It provides 4 differential, non-isolated analog input channels with per-channel input type selection. Unlike the 5069-IF8, which handles only voltage and current signals, the IY4 adds native RTD and thermocouple support — reading temperature directly in engineering units without an external temperature transmitter.
Catalog Number Breakdown
| Code | Meaning | Value |
|---|---|---|
| 5069 | Platform | Compact 5000 — high-speed backplane I/O bus |
| I | Direction | Input module |
| Y | Signal type | Current, voltage, RTD, or thermocouple per channel |
| 4 | Channel count | 4 differential channels |
Key Specifications (from 5069-TD001)
| Parameter | Value |
|---|---|
| Input Channels | 4 differential, non-isolated |
| Input Types (per channel) | Current: 0–20mA, 4–20mA | Voltage: 0–5V, 0–10V, ±10V | RTD | Thermocouple | Millivolt (±100mV) |
| RTD Sensor Types | 100, 200, 500, 1000 Ω PT 385 | 100, 200, 500, 1000 Ω PT 3916 | 10 Ω CU 427 | 120 Ω NI 672 | 100, 120, 200, 500 Ω NI 618 |
| Thermocouple Types | B, C, D, E, J, K, N, R, S, T, TXK/XK(L) |
| Temperature Units | Celsius, Fahrenheit, Kelvin, Rankine, Custom |
| Resolution (16-bit at 10 Hz notch filter) | Voltage: <320 µV/count (±10.5V), <160 µV/count (0–10.5V), <80 µV/count (0–5.25V) | Current: <0.32 µA/count (0–21 mA) | RTD: <7.9 mΩ/count (1–500 Ω) to <63.4 mΩ/count (8–4000 Ω) | TC/mV: <3.1 µV/count (±100 mV) |
| Accuracy at 25°C | Voltage: 0.100% FS | Current: 0.100% FS | RTD: 0.100% FS | TC/mV: 0.100% FS |
| Accuracy Drift with Temperature | Voltage: 0.200% FS | Current: 0.300% FS | RTD: 0.200% FS | TC/mV: 0.200% FS |
| Input Impedance | Voltage: >1 MΩ | Current: 90 Ω typical (70–110 Ω range) | RTD: >1 MΩ | TC/mV: >1 MΩ |
| RTD Excitation Current | 600 µA (3-wire mode) | 100 µA (2-wire mode) |
| Noise Rejection Ratio | Common mode: 130 dB @ 50/60 Hz | Normal mode: 65 dB @ 50/60 Hz (notch filter dependent) |
| CJC Inputs | 2 CJC sensors embedded in 5069-RTB14CJC RTB (thermocouple mode only) |
| CJC Sensor Accuracy | Local: ±0.54°F (±0.3°C) | Remote: ±0.54°F (±0.3°C) |
| Scan Time | 625 µs per channel | Per group (Ch 0–3): 2.5 ms |
| Notch Filter | 5, 10, 15, 20, 50, 60 Hz (default), 100, 200, 500, 1000, 2500, 5000, 10000, 15625, 25000, 31250, 62500 Hz |
| Module Conversion Method | Sigma-Delta, one 24-bit multiplexed ADC |
| Data Format | IEEE 754, 32-bit floating point (REAL) |
| Isolation | 250V continuous (Basic Insulation). 50V Functional Isolation between SA power and input ports. No isolation between individual input ports. |
| Terminal Block | Standard: 5069-RTB18-SPRING or 5069-RTB18-SCREW (18-pin) | CJC: 5069-RTB14CJC-SPRING or 5069-RTB14CJC-SCREW (14-pin with built-in CJC thermistors) |
| Power Consumption (max) | Voltage: 1.8W | Current: 2.1W | RTD: 2.1W | TC/mV: 1.8W. MOD power: 75mA @ 18–32V DC. SA power: 100mA @ 18–32V DC. |
| Dimensions | 144.6 x 22 x 105.4 mm (5.69 x 0.87 x 4.15 in.) |
| Operating Temperature | 0–60°C (32–140°F) |
| Thermocouple Linearization | ITS-90 |
IY4 vs. IF8 — When to Use Which
| Feature | 5069-IY4 | 5069-IF8 |
|---|---|---|
| Channels | 4 differential | 8 (Series A: differential, Series B: single-ended) |
| Current/Voltage | Yes | Yes |
| RTD Input | Yes (2-wire and 3-wire) | No |
| Thermocouple Input | Yes (all standard types) | No |
| Millivolt Input | Yes (±100 mV) | No |
| Cold Junction Compensation | Yes (CJC RTB required) | Not applicable |
| Terminal Block | 14-pin (CJC) or 18-pin (standard) | 18-pin |
| Best For | Direct temperature measurement, mixed signal types on a single module | High channel density for current/voltage signals only |
One Module, Four Signal Types
The 5069-IY4 allows each channel to be independently configured. Channel 0 can read a Type K thermocouple, Channel 1 a PT100 RTD, Channel 2 a 4–20mA pressure transmitter, and Channel 3 a 0–10V position feedback — all on the same module. This flexibility reduces spare parts inventory and simplifies mixed-signal applications.
2. Hardware Installation
The 5069-IY4 mounts on an EN50022 35 x 7.5 mm (1.38 x 0.30 in.) DIN rail as part of the Compact 5000 system assembly. Modules interlock side by side and pass MOD power, SA power, and backplane communication module to module -- there is no separate chassis. A CompactLogix 5380 controller (or a 5069-AENTR / 5069-AEN2TR adapter for remote I/O) supplies MOD and SA power to the modules; each is fed from external 24VDC power wired to the controller's or adapter's MOD and SA power terminal blocks. There is no separate 5069 power supply module.
RTB Selection — Standard vs. CJC
The terminal block you order depends on whether any channel will use thermocouple input:
| RTB Catalog Number | Type | Pins | When to Use |
|---|---|---|---|
| 5069-RTB14CJC-SPRING | CJC (spring-clamp) | 14 | Required if at least one channel uses thermocouple input. Contains built-in CJC thermistors for cold junction compensation. |
| 5069-RTB14CJC-SCREW | CJC (screw-terminal) | 14 | Same as above, screw-terminal style. RTB torque: 0.4 N·m (3.5 lb·in). |
| 5069-RTB18-SPRING | Standard (spring-clamp) | 18 | Use when no thermocouples are connected. Recommended for current, voltage, and RTD-only applications. |
| 5069-RTB18-SCREW | Standard (screw-terminal) | 18 | Same as above, screw-terminal style. |
CJC RTB is Mandatory for Thermocouples
If even one channel is configured for thermocouple input, you must use the 5069-RTB14CJC RTB. The CJC RTB contains thermistors that measure the temperature at the terminal block where the thermocouple wire transitions to copper. Without this compensation, thermocouple readings will be inaccurate. If no thermocouples are used, the standard 5069-RTB18 RTB is recommended.
System Assembly Order
| Position | Module | Example |
|---|---|---|
| Slot 0 (leftmost) | Controller or adapter | CompactLogix 5380 (e.g., 5069-L306ER), Compact GuardLogix 5380, CompactLogix 5480, or a 5069-AENTR EtherNet/IP adapter for remote I/O |
| Slot 1 onward | I/O Modules | 5069-IY4 in any available slot. Maximum local modules depends on the controller: 8 for the 5069-L306ER and 5069-L310ER, 16 for the 5069-L320ER, 31 for the 5069-L330ER and larger. |
| Rightmost | End Cap | Required on the last module in the system. Install it only after the last module is in place; pushing it past the locked position or inserting it backwards can damage the MOD and SA power bus connectors. |
Mounting Procedure
- Confirm that MOD power and all sources of SA power are off.
- If an end cap is installed on the right-most module, remove it and keep it for later use.
- Confirm that the DIN rail latch is closed. If it is open, gently push the rear latch back until the front latch pops up and clicks.
- Align the interlocking pieces of the module with the device on the left. The top interlocking pieces engage first.
- Push the module toward the DIN rail until a click indicates it is locked in place.
- Hook the bottom of the RTB into the RTB tab on the module, then push the RTB against the module until it clicks into place. Push the RTB handle until you hear another click.
- Install the end cap on the last module by aligning the interlocking pieces and pushing toward the DIN rail until it locks.
No Hot-Swap (RIUP) Support
The 5069-IY4 does not support Removal and Insertion Under Power (RIUP). Remove MOD power and all sources of SA power before inserting or removing the module. Do not connect or disconnect the removable terminal block (RTB) with power applied — an electric arc can occur, which could cause an explosion in hazardous location installations. Confirm that power is removed before proceeding.
Electrostatic Discharge
This equipment is sensitive to electrostatic discharge. Touch a grounded object to discharge potential static before handling. Wear an approved grounding wrist strap. Do not touch circuit connectors or pins on component boards.
3. Wiring
The 5069-IY4 uses either a 14-pin CJC RTB (for thermocouple applications) or an 18-pin standard RTB. Each channel uses three terminals: Input +, Input −, and RTD −/Com. Two shield terminals are shared across all channels (both the 18-pin and the 14-pin CJC RTB have them). Wire size: 0.34–1.5 mm² (22–16 AWG) solid or stranded shielded copper wire rated at 105°C (221°F) or greater.
Terminal Block Pinout — 18-Pin Standard RTB (5069-RTB18)
| Pin | Terminal Name | Function |
|---|---|---|
| 0–1 | (Unused) | Not connected on the IY4 |
| 2 | Input 0 + | Channel 0 positive input |
| 3 | Input 0 − | Channel 0 negative input |
| 4 | RTD −/Com | Channel 0 RTD common (3rd wire for 3-wire RTD) |
| 5 | Input 1 + | Channel 1 positive input |
| 6 | Input 1 − | Channel 1 negative input |
| 7 | RTD −/Com | Channel 1 RTD common |
| 8 | Input 2 + | Channel 2 positive input |
| 9 | Input 2 − | Channel 2 negative input |
| 10 | RTD −/Com | Channel 2 RTD common |
| 11–12 | (Unused) | Not connected on the IY4 |
| 13 | Input 3 + | Channel 3 positive input |
| 14 | Input 3 − | Channel 3 negative input |
| 15 | RTD −/Com | Channel 3 RTD common |
| 16 | Shield | Cable shield/drain wire (1 wire per terminal max) |
| 17 | Shield | Cable shield/drain wire (1 wire per terminal max) |
The 14-pin CJC RTB carries the 12 channel terminals (Input +, Input −, RTD −/Com for channels 0–3) and the two Shield terminals; the unused positions of the 18-pin RTB are omitted. See the thermocouple wiring diagram in 5069-IN011 for its layout. If you need to ground more than two device shields, ground the remaining devices elsewhere (e.g., DIN rail via a terminal strip).
2-Wire Current Transmitter (4–20mA or 0–20mA)
A 2-wire loop-powered current transmitter is powered from an external 24VDC supply. The current signal flows through the transmitter and into the module input.
- 24VDC power supply (+) connects to the transmitter's positive terminal
- Transmitter negative terminal connects to the module's Input x + pin for that channel
- Module Input x − pin connects back to the 24VDC power supply (−), completing the loop
- Connect the cable shield/drain wire to a Shield terminal (Pin 16 or 17 on the 18-pin RTB)
- The RTD −/Com terminal is not used for current input
Additional Loop Devices
When an analog current device is connected to the module, place additional loop devices (e.g., strip chart recorders) at either A location in the current loop.
Voltage Input (0–5V, 0–10V, or ±10V)
Single-ended and differential voltage sources are both supported:
- Connect the signal source's voltage output (+) to the module's Input x +
- Connect the signal source's voltage output (−) / GND to the module's Input x −
- Connect the cable shield/drain wire to a Shield terminal
- The RTD −/Com terminal is not used for voltage input
3-Wire RTD
The 3-wire RTD configuration is the most common for industrial platinum RTDs (e.g., PT100). The third wire allows the module to compensate for lead wire resistance.
- Connect RTD wire 1 to the module's Input x +
- Connect RTD wire 2 to the module's Input x −
- Connect RTD wire 3 (compensation lead) to the module's RTD −/Com
- Connect the cable shield to a Shield terminal — ground at the module end only
Wire Impedance Requirement
For 3-wire RTD mode, wire impedance must be 25 Ω maximum for specified accuracy. Use low-resistance copper conductors and keep cable runs as short as practical.
2-Wire RTD
2-wire RTDs have no lead wire resistance compensation. They are acceptable for short cable runs or where lower accuracy is tolerable.
- Connect RTD wire 1 to the module's Input x +
- Connect RTD wire 2 to the module's Input x −
- If the channel is configured for 3-wire RTD mode, jumper the Input x − terminal to the RTD −/Com terminal on the same channel. In 2-wire RTD mode, connect only Input x + and Input x −.
- Connect the cable shield to a Shield terminal
2-Wire RTD on a 3-Wire Channel Needs a Jumper
When you connect a 2-wire RTD to a channel configured for 3-wire mode, you must jumper Input x− and RTD −/Com together (5069-IN011). A channel configured for 2-wire mode needs no jumper.
Thermocouple
Thermocouple wiring requires the 5069-RTB14CJC terminal block for cold junction compensation. The CJC RTB contains thermistors that measure the terminal temperature.
- Connect the thermocouple positive (+) lead to the module's Input x +
- Connect the thermocouple negative (−) lead to the module's Input x −
- The RTD −/Com terminal is not used for thermocouple input
- Connect the cable shield to a Shield terminal (the CJC RTB has two). Ground any additional shields at the DIN rail via a terminal strip.
Use Thermocouple Extension Wire
The cable from the thermocouple to the module terminal block must be thermocouple extension wire (or the thermocouple wire itself) of the same type as the sensor. Using standard copper wire introduces additional thermoelectric junctions that cause measurement errors. The transition from thermocouple wire to copper happens at the RTB terminal — this is the cold junction that the CJC RTB compensates for.
Mixed Input Type Wiring
The 5069-IY4 supports mixing all four input types on a single module. For example, one module can simultaneously read a 2-wire differential current transmitter on Channel 0, a single-ended voltage signal on Channel 1, a 3-wire RTD on Channel 2, and a thermocouple on Channel 3. When any channel uses a thermocouple, the CJC RTB (5069-RTB14CJC) is required for the entire module.
Shielded Cable and Grounding Best Practices
Analog Signal Wiring Rules
- Always use shielded, twisted-pair cable for analog signals.
- Ground the shield at one end only (the module end) to prevent ground loops.
- This module has only two shield terminals. If more than two devices are connected, ground the remaining shields at the DIN rail via a terminal strip. Use the same power supply to power the additional devices and ground the power supplies at the same ground location.
- Do not wire more than 1 conductor on any single RTB terminal.
- Use separate external power supplies for SA power to the system and to power external devices connected to the module.
- Route analog cables in separate conduit from power wiring, following the routing rules in publication 1770-4.1.
- The 5069-IY4 uses DC SA power. Connect DC power from the controller, adapter, or field potential distributor that provides SA power to the modules.
4. Studio 5000 Configuration
Adding the 5069-IY4 to the I/O Tree
- In Studio 5000 Logix Designer, expand I/O Configuration in the Controller Organizer
- Right-click the controller node → New Module
- In the module catalog, search for
5069-IY4→ select it → click Create - Set the Slot Number to match the physical position of the module in the Compact 5000 assembly (the controller is slot 0; the first module to its right is slot 1)
- Give the module a descriptive name (e.g.,
Temp_Inputs_1) - Click OK. The module appears in the I/O tree with Channels and CJ Channels configuration nodes.
Per-Channel Configuration (Channels Page)
Double-click the module in the I/O tree and navigate to the Channels page. Each channel (Ch00–Ch03) is configured independently:
| Setting | Options | Notes |
|---|---|---|
| Disable Channel | Checked / Unchecked | A disabled channel turns its I/O status indicator off and sets its Chxx.Fault tag to 1. |
| Input Type | Current / Voltage / RTD / Thermocouple | Must match the physical device wired to that channel. |
| Input Range | Depends on Input Type (see table below) | For RTD, the range is automatically set based on the selected Sensor Type. |
| Sensor Type | RTD or TC specific (see Sensor Types table below) | Only visible when Input Type = RTD or Thermocouple. |
| Temperature Units | Celsius / Fahrenheit / Kelvin / Rankine / Custom | Only visible for RTD and Thermocouple input types. Determines the engineering units of the Ch.Data tag. |
Input Ranges by Type
| Input Type | Sensor Type | Available Input Ranges |
|---|---|---|
| Current (mA) | — | 0–20 mA | 4–20 mA |
| Voltage (V) | — | ±10V | 0–5V | 0–10V |
| RTD | 100 Ω PT 385 | 1–500 Ω |
| 200 Ω PT 385 | 2–1000 Ω | |
| 500 Ω PT 385 | 4–2000 Ω | |
| 1000 Ω PT 385 | 8–4000 Ω | |
| 100 Ω PT 3916 | 1–500 Ω | |
| 200 Ω PT 3916 | 2–1000 Ω | |
| 500 Ω PT 3916 | 4–2000 Ω | |
| 1000 Ω PT 3916 | 8–4000 Ω | |
| 10 Ω CU 427 | 1–500 Ω | |
| 120 Ω NI 672 | 1–500 Ω | |
| 100 Ω NI 618 | 1–500 Ω | |
| 120 Ω NI 618 | 1–500 Ω | |
| 200 Ω NI 618 | 2–1000 Ω | |
| 500 Ω NI 618 | 4–2000 Ω | |
| Thermocouple | mV or any TC type | −100–+100 mV |
Temperature Range Limits (Selected Common Types)
| Input Type | Sensor Type | Temperature Range (Celsius) | Temperature Range (Fahrenheit) |
|---|---|---|---|
| RTD | 100–1000 Ω PT 385 | −200 to +870°C | −328 to +1598°F |
| RTD | 100–1000 Ω PT 3916 | −200 to +630°C | −328 to +1166°F |
| RTD | 10 Ω CU 427 | −200 to +260°C | −328 to +500°F |
| RTD | 120 Ω NI 672 | −80 to +320°C | −112 to +608°F |
| RTD | 100–500 Ω NI 618 | −60 to +250°C | −76 to +482°F |
| TC | Type J | −210 to +1200°C | −346 to +2192°F |
| TC | Type K | −270 to +1372°C | −454 to +2502°F |
| TC | Type T | −270 to +400°C | −454 to +752°F |
| TC | Type E | −270 to +1000°C | −454 to +1832°F |
| TC | Type N | −270 to +1300°C | −454 to +2372°F |
| TC | Type R | −50 to +1768°C | −58 to +3215°F |
| TC | Type S | −50 to +1768°C | −58 to +3215°F |
| TC | Type B | 21 to 1820°C | 68 to 3308°F |
| TC | Type C | 0 to 2320°C | 32 to 4208°F |
| TC | Type D | 0 to 2320°C | 32 to 4208°F |
| TC | TXK/XK(L) | −200 to +800°C | −328 to +1472°F |
Additional Channel Configuration Parameters
Each channel’s configuration page (accessed via the Chxx node in Module Properties) provides these additional settings:
| Configuration Tag | Description |
|---|---|
C.Ch00.NotchFilter | Notch filter frequency — attenuates AC line noise. Default 60 Hz. Set to 50 Hz in 50 Hz power environments. Higher values allow faster sample rates. |
C.Ch00.DigitalFilter | First-order lag filter time constant in ms (0 = disabled, max 32,767 ms). Smooths input noise transients. The input reaches 63% of a step change after one time constant. |
C.Ch00.OpenWireEn | Enable/disable open wire detection. Available for all input types (current, voltage, RTD, thermocouple). |
C.Ch00.AlarmDisable | Disable all process alarms on the channel. Note: this does not disable underrange/overrange or open wire detection. |
C.Ch00.ProcessAlarmLatchEn | When enabled, process alarms latch and must be manually unlatched via the O.Chxx.xxxAlarmUnlatch tags. |
C.Ch00.RateAlarmLatchEn | When enabled, the rate alarm latches until manually unlatched. |
C.Ch00.TenOhmOffset | 10 Ohm Copper Offset — compensates for a small offset error in a 10 Ω copper RTD (CU 427 sensor type only). Value in units of 0.01 Ω. |
C.Ch00.LowSignal / HighSignal | Scaling low/high signal values. For RTD/TC input types, these default to the lowest and highest temperature that the selected sensor type supports. You can change them if necessary. |
C.Ch00.LowEngineering / HighEngineering | Scaling low/high engineering values. For RTD/TC, automatically set equal to LowSignal/HighSignal. |
C.Ch00.LLAlarmLimit | Low-Low alarm trigger point in engineering units. |
C.Ch00.LAlarmLimit | Low alarm trigger point. |
C.Ch00.HAlarmLimit | High alarm trigger point. |
C.Ch00.HHAlarmLimit | High-High alarm trigger point. |
C.Ch00.RateAlarmLimit | Rate of change alarm limit in engineering units per second. |
C.Ch00.AlarmDeadband | Alarm deadband — prevents alarm chatter. The alarm status bit remains set as long as the input data stays within the deadband of the alarm threshold. |
Notch Filter and RPI Relationship
The Notch Filter setting determines the module’s sample rate and thus the minimum recommended RPI (Requested Packet Interval). Lower frequencies provide better noise rejection but require a slower RPI.
| Notch Filter | Min RPI (1 Channel) | Min RPI (All 4 Channels, Same Filter) |
|---|---|---|
| 5 Hz | 215 ms (faster) / 635 ms (better noise) | 750 ms (faster) |
| 10 Hz | 110 ms / 320 ms | 440 ms |
| 50 Hz | 25 ms / 70 ms | 100 ms / 280 ms |
| 60 Hz (default) | 20 ms / 60 ms | 80 ms / 240 ms |
| 100 Hz | 15 ms / 35 ms | 60 ms / 140 ms |
| 500 Hz | 5 ms / 10 ms | 20 ms / 40 ms |
| 1000 Hz | 2 ms / 5 ms | 8 ms / 20 ms |
| 5000 Hz | 1 ms / 2 ms | 4 ms / 8 ms |
| 62,500 Hz | — / 0.7 ms | — / 2.8 ms |
Temperature Measurement Typically Uses Low Notch Filters
Temperature processes change slowly. For RTD and thermocouple inputs, a 50 Hz or 60 Hz notch filter provides excellent noise rejection with an update rate that is more than fast enough for thermal processes. Only increase the notch filter frequency if you need to capture rapid temperature transients (e.g., injection molding barrel zone control).
5. Reading Temperature in Ladder Logic
Data Format
For RTD and thermocouple input types, the I.Chxx.Data tag contains the temperature reading directly in the configured temperature units (Celsius, Fahrenheit, Kelvin, or Rankine) as a REAL (floating-point) value. No SCP instruction or manual scaling is required for temperature — the module performs the sensor linearization (ITS-90 for thermocouples) and unit conversion internally.
For current and voltage input types, the I.Chxx.Data tag contains the signal-level value (mA or V). Use the module’s built-in Scaling feature or an SCP instruction to convert to process engineering units.
Input Tag Structure (Module in Slot 2 Example)
| Tag | Data Type | Description |
|---|---|---|
Local:2:I.Ch00.Data | REAL | Channel 0 data in engineering units (temperature or signal level) |
Local:2:I.Ch01.Data | REAL | Channel 1 data |
Local:2:I.Ch02.Data | REAL | Channel 2 data |
Local:2:I.Ch03.Data | REAL | Channel 3 data |
Local:2:I.Ch00.RollingTimestamp | INT | 15-bit ms timer recorded when module scans its channels. Use to calculate time between samples. |
Practical Example: Type K Thermocouple and PT100 RTD
Scenario: Channel 0 reads a Type K thermocouple measuring furnace temperature (configured for Celsius). Channel 1 reads a 3-wire PT100 RTD (100 Ω PT 385) measuring cooling water temperature (configured for Fahrenheit). The module is in Slot 2.
// -- Temperature Reading & Alarm Routine ------------------------------------------
// Tag definitions:
// Furnace_Temp (alias) -> Local:2:I.Ch00.Data (REAL, degrees C)
// CoolWater_Temp (alias) -> Local:2:I.Ch01.Data (REAL, degrees F)
// Furnace_HiAlarm -> BOOL, high temperature alarm
// Furnace_OpenWire -> (alias) -> Local:2:I.Ch00.OpenWire (BOOL)
// Furnace_Fault -> BOOL, latched sensor fault
// CoolWater_LoAlarm -> BOOL, low temperature alarm
// ---------------------------------------------------------------------------------
// Rung 1 -- Furnace high temperature alarm at 850 deg C
IF Furnace_Temp >= 850.0 THEN
Furnace_HiAlarm := 1;
ELSE
Furnace_HiAlarm := 0;
END_IF;
// Rung 2 -- Open-wire detection fault latch (thermocouple disconnected)
IF Furnace_OpenWire THEN
Furnace_Fault := 1;
END_IF;
// Rung 3 -- Cooling water low temperature alarm at 40 deg F
IF CoolWater_Temp <= 40.0 THEN
CoolWater_LoAlarm := 1;
ELSE
CoolWater_LoAlarm := 0;
END_IF;
// Rung 4 -- Fault reset (operator pushbutton or HMI button)
IF PB_FaultReset AND NOT Furnace_OpenWire THEN
Furnace_Fault := 0;
END_IF;
No SCP Needed for Temperature
Unlike current/voltage inputs that require scaling, RTD and thermocouple channels deliver temperature directly in the
I.Chxx.Data tag. The module handles linearization internally (ITS-90 for thermocouples). Simply read the tag and compare against your alarm setpoints.
Using Module-Level Process Alarms
Instead of (or in addition to) comparison instructions in ladder logic, you can use the module's built-in 4-level process alarm system. This requires enabling alarms via the output tags and configuring setpoints in the module properties:
- In Module Properties → Alarms page, set the
HHAlarmLimit,HAlarmLimit,LAlarmLimit, andLLAlarmLimitfor each channel (values are in the channel’s engineering units) - Optionally enable alarm latching via
C.Chxx.ProcessAlarmLatchEn - In your ladder logic, write 1 to the output enable tags to activate each alarm level:
// Enable all 4 process alarm levels on Channel 0 (run once at startup)
Local:2:O.Ch00.HHAlarmEn := 1;
Local:2:O.Ch00.HAlarmEn := 1;
Local:2:O.Ch00.LAlarmEn := 1;
Local:2:O.Ch00.LLAlarmEn := 1;
Local:2:O.Ch00.RateAlarmEn := 1;
// Monitor alarm status in I.Chxx tags:
// Local:2:I.Ch00.HHAlarm -- High-High alarm active
// Local:2:I.Ch00.HAlarm -- High alarm active
// Local:2:I.Ch00.LAlarm -- Low alarm active
// Local:2:I.Ch00.LLAlarm -- Low-Low alarm active
// Local:2:I.Ch00.RateAlarm -- Rate of change alarm active
// To unlatch a latched alarm (after condition clears):
Local:2:O.Ch00.HHAlarmUnlatch := 1;
// Then reset the unlatch tag back to 0:
Local:2:O.Ch00.HHAlarmUnlatch := 0;
Unlatch Alarm Procedure
When alarm latching is enabled, you must toggle the Unlatch tag from 0 to 1 to unlatch the alarm. You must also toggle it back to 0 after unlatching. If you leave the tag at 1 and the alarm is latched again in the future, it remains latched because the tag is already 1.
6. Cold Junction Compensation
What is Cold Junction Compensation?
A thermocouple generates a millivolt signal proportional to the temperature difference between its measurement tip (the hot junction) and the point where the thermocouple wire transitions to copper (the cold junction). In the 5069-IY4 system, the cold junction occurs at the RTB terminals where the thermocouple extension wire connects to the module’s copper circuitry.
The thermoelectric effect at this junction alters the input signal and must be compensated for to measure temperatures accurately. The CJC RTB (5069-RTB14CJC-SPRING or 5069-RTB14CJC-SCREW) contains two thermistors that measure the RTB terminal temperature. The module uses this measurement to mathematically compensate for the cold junction voltage, producing an accurate hot junction temperature reading.
CJC RTB Requirements
| Attribute | Value |
|---|---|
| CJC Sensors | 2 thermistors embedded in the 5069-RTB14CJC RTB |
| Alternative | 2 thermistors wired to a 5069-RTB18 RTB (thermistor type: Measurement Specialties, Inc. 10K3A1A) |
| Local CJC Sensor Accuracy | ±0.54°F (±0.3°C) |
| Remote CJC Sensor Accuracy | ±0.54°F (±0.3°C) based on specified thermistor |
CJC Diagnostic Tags
The module provides dedicated cold junction diagnostic tags (CJChxx) in addition to the standard channel tags. These are visible in the I/O tree under CJ Channels:
| Tag | Data Type | Description |
|---|---|---|
Local:X:I.CJChxx.Temperature | REAL | Current temperature of the cold junction at this CJC sensor. Useful for verifying the RTB is at a stable, reasonable temperature. |
Local:X:I.CJChxx.Fault | BOOL | Cold junction data quality is bad. Check CJC RTB installation and thermistor connections. |
Local:X:I.CJChxx.OpenWire | BOOL | A wire is disconnected from the cold junction sensor. |
Local:X:I.CJChxx.Uncertain | BOOL | Cold junction data may be imperfect but degree of inaccuracy is unknown. |
Local:X:I.CJChxx.Underrange | BOOL | Cold junction at the channel is beneath the absolute minimum for this channel. |
Local:X:I.CJChxx.Overrange | BOOL | Cold junction at the channel is above the absolute maximum for this channel. |
Local:X:I.CJChxx.FieldPowerOff | BOOL | Field power is not present at the cold junction. |
Monitoring CJC Temperature
In thermocouple applications, periodically check the
I.CJChxx.Temperature tag to verify the RTB temperature is reasonable (typically close to ambient). If the CJC temperature is unusually high (e.g., near a heat source) or fluctuating, thermocouple accuracy suffers. Mount the module away from heat-generating equipment and ensure adequate ventilation.
CJC Compensation Can Be Disabled
The CJ Channels configuration page in Module Properties allows you to disable either cold junction sensor (CJCh00 or CJCh01). If only one is disabled, the module uses the other; if both are disabled, the module assumes a cold junction temperature of 0. Do not disable CJC for standard thermocouple temperature measurement.
7. Diagnostics & Troubleshooting
LED Indicators
The 5069-IY4 has one green/red Module Status (MOD) indicator, four yellow/red I/O status indicators (one per channel), and two yellow/red CJC status indicators.
| LED | State | Meaning |
|---|---|---|
| MOD (Module Status) | Solid green | Module operating normally |
| MOD | Flashing green | Module is powered but has no connection to the controller |
| MOD | Solid red | Unrecoverable fault — replace module |
| MOD | Flashing red | Recoverable fault — check configuration, reset |
| I/O (per channel) | Steady yellow | Channel operating normally |
| I/O | Flashing red | External fault: overrange/underrange, open wire, or SA power not present |
| I/O | Steady red | Internal fault, calibration fault, or over temperature |
| I/O | Alternating yellow/red | Calibration in progress |
| I/O | Off | Not powered, no connection, or channel disabled |
Complete Input Tag Reference (I.Chxx)
Every channel (Ch00–Ch03) provides the following diagnostic and data tags:
| Tag | Data Type | Description |
|---|---|---|
I.Chxx.Data | REAL | Channel data in scaled engineering units (temperature for RTD/TC, signal level for V/mA) |
I.Chxx.RollingTimestamp | INT | 15-bit ms timer recorded when module scans. Use to calculate time between samples. |
I.Chxx.Fault | BOOL | Channel data quality is bad |
I.Chxx.Uncertain | BOOL | Channel data may be imperfect — degree of inaccuracy unknown |
I.Chxx.OpenWire | BOOL | Open wire detected. Cause depends on mode: Current = signal below 100 µA; Voltage = signal reaches full-scale; RTD = wire disconnected; TC = wire disconnected. |
I.Chxx.OverTemperature | BOOL | Module operating above its rated temperature limits |
I.Chxx.FieldPowerOff | BOOL | Field power not present on the channel |
I.Chxx.NotANumber | BOOL | Most recently received data value was not a valid number |
I.Chxx.Underrange | BOOL | Channel data is beneath the absolute minimum for the configured range |
I.Chxx.Overrange | BOOL | Channel data is above the absolute maximum for the configured range |
I.Chxx.LLAlarm | BOOL | Low-Low process alarm active |
I.Chxx.LAlarm | BOOL | Low process alarm active |
I.Chxx.HAlarm | BOOL | High process alarm active |
I.Chxx.HHAlarm | BOOL | High-High process alarm active |
I.Chxx.RateAlarm | BOOL | Rate of change alarm active — signal changing faster than configured RateAlarmLimit |
I.Chxx.CalFault | BOOL | Calibration fault on the channel |
I.Chxx.Calibrating | BOOL | Channel calibration in progress — do not rely on data |
Complete Output Tag Reference (O.Chxx)
| Tag | Data Type | Description |
|---|---|---|
O.Chxx.LLAlarmEn | BOOL | Write 1 to enable the Low-Low process alarm |
O.Chxx.LAlarmEn | BOOL | Write 1 to enable the Low process alarm |
O.Chxx.HAlarmEn | BOOL | Write 1 to enable the High process alarm |
O.Chxx.HHAlarmEn | BOOL | Write 1 to enable the High-High process alarm |
O.Chxx.RateAlarmEn | BOOL | Write 1 to enable the Rate of change alarm |
O.Chxx.LLAlarmUnlatch | BOOL | Toggle 0 → 1 to unlatch the Low-Low alarm (then reset to 0) |
O.Chxx.LAlarmUnlatch | BOOL | Toggle to unlatch the Low alarm |
O.Chxx.HAlarmUnlatch | BOOL | Toggle to unlatch the High alarm |
O.Chxx.HHAlarmUnlatch | BOOL | Toggle to unlatch the High-High alarm |
O.Chxx.RateAlarmUnlatch | BOOL | Toggle to unlatch the Rate alarm |
O.Chxx.SensorOffset | REAL | Sensor offset calibration in signal units. Added to the data value to compensate for known sensor error. |
Fault Tags (Module-Level)
| Tag | Description |
|---|---|
ConnectionFaulted | Owner-controller lost connection to the module. Affects all channels simultaneously. |
RunMode | Module is in Run Mode — provides module-wide data and affects all channels. |
DiagnosticActive | Indicates if any diagnostics are active. |
DiagnosticSequenceCount | Counter that increments when a diagnostic condition occurs or goes away. Rolling counter that skips 0 on rollovers. |
Common Troubleshooting Scenarios
| Symptom | Likely Cause | Resolution |
|---|---|---|
| Thermocouple reads ambient temperature instead of process temperature | Thermocouple wires reversed (+ and − swapped) or wrong thermocouple type selected | Verify polarity at the terminal block. Confirm the Sensor Type in Studio 5000 matches the actual thermocouple type. |
| Thermocouple reading has a large offset | Standard RTB used instead of CJC RTB, or CJC disabled in configuration | Install a 5069-RTB14CJC RTB. Verify CJC is enabled in the CJ Channels configuration page. |
| RTD reads a fixed high or low value | Open wire on the RTD circuit, or missing jumper on a 2-wire RTD wired to a 3-wire-mode channel | Check wiring continuity. For a 2-wire RTD on a channel configured for 3-wire mode, verify the Input x− to RTD −/Com jumper is installed. |
| RTD reading drifts or is inaccurate | Lead wire resistance too high (3-wire mode), or 2-wire RTD on a long cable run | Verify wire impedance is below 25 Ω. Use 3-wire RTDs for better accuracy. Shorten cable runs or use larger gauge wire. |
| Open-wire alarm on thermocouple channel | Broken thermocouple junction, loose terminal connection, or extension wire break | Measure thermocouple resistance with a multimeter (should be low ohms). Reseat terminal connections. Replace thermocouple if junction is open. |
| Reading fluctuates or has excessive noise | Electrical noise, ground loop, or unshielded cable | Use shielded cable. Ground shield at one end only. Reduce notch filter frequency (50/60 Hz). Increase digital filter time constant. Separate analog cables from power wiring. |
| CJChxx.Fault is set | CJC thermistor in the RTB is damaged or the CJC RTB is not properly seated | Reseat the RTB. If fault persists, replace the CJC RTB (5069-RTB14CJC). |
| OverTemperature alarm on all channels | Ambient temperature exceeds module’s 60°C (140°F) operating limit | Check enclosure temperature. Improve ventilation. Reduce heat dissipation from adjacent modules. |
| Module shows yellow triangle in I/O tree | Slot mismatch, firmware mismatch, or module not physically seated | Verify slot number matches physical position. Check that the module is locked on the DIN rail, interlocked with its neighbors, and that the end cap is installed. Update firmware if needed. |
Match the Input Type to the Wiring
RTD and thermocouple inputs expect millivolt-level or resistance signals. Applying a signal that does not match the configured Input Type gives meaningless readings and faults. Always confirm the Input Type before connecting field wiring.
8. Related Modules
| Catalog Number | Channels | Signal Type | Key Feature |
|---|---|---|---|
| 5069-IY4K | 4 differential | Current / Voltage / RTD / Thermocouple | Conformal-coated version of the 5069-IY4 for harsh or corrosive environments. Identical functionality and wiring. |
| 5069-IF8 | 8 (Series A: differential, Series B: single-ended) | Voltage / Current (per channel) | Higher channel density for current and voltage signals only. Does not support RTD or thermocouple. Use when temperature measurement is not required. |
| 5069-IF4IH | 4 (individually isolated) | Voltage / Current / HART | 4-channel isolated current/voltage/HART input module. Supports HART pass-through for smart transmitter configuration. Does not support RTD/TC. |
IY4 vs. Temperature Transmitter + IF8
For temperature measurement, you have two paths: wire the RTD or thermocouple directly to the 5069-IY4, or use a temperature transmitter that converts to 4–20mA and wire to the 5069-IF8. Direct input to the IY4 is lower cost per channel, simpler to wire, and provides native diagnostic tags for the sensor. Transmitter-based input via the IF8 is better for long cable runs (4–20mA is noise-immune over distance), when you need HART diagnostics, or when you need galvanic isolation at the field device.
9. Related Guides & Resources
| Resource | Description |
|---|---|
| 5069-IF8 Analog Input Guide | Configuration and wiring for the 8-channel Compact 5000 current/voltage analog input module. |
| CompactLogix 5069-L306ER Setup Guide | First-time controller setup, power wiring, Studio 5000 project creation, and basic ladder logic for the Compact 5000 platform. |
| PLC Sensor Calibration & Scaling (Blog) | In-depth tutorial on analog sensor scaling with worked examples for pressure, temperature, and flow applications. |
Reference Documentation
The following Rockwell Automation publications were used as references for this guide. These are the official manufacturer documents for the hardware covered in this article.
| Publication | Description | Download |
|---|---|---|
| 5069-UM005 | Compact 5000 Analog I/O Modules User Manual | |
| 5069-IN011 | 5069-IY4 Installation Instructions | |
| 5069-TD001 | Compact 5000 I/O Technical Data |
Shop the Compact 5000 I/O Range
Thermocouple, RTD, and analog I/O modules from the Compact 5000 family.