1734-IB8: Installation, Wiring, Configuration, and Programming Guide
The 1734-IB8 is an 8-channel 24VDC sinking digital input module for the Allen-Bradley POINT I/O platform. It connects to a controller via a POINT I/O communication adapter (1734-AENT for EtherNet/IP, 1734-ACNR for ControlNet, or 1734-ADN for DeviceNet) across the POINTBus backplane. The POINT I/O system uses a modular 3-piece design: terminal base, I/O module, and removable terminal block (RTB). This guide covers system assembly, field wiring, Studio 5000 configuration, ladder logic examples, and LED diagnostics.
Contents
1. Module Overview
The 1734-IB8 is a fixed 8-point sinking digital input module for the POINT I/O platform. It reads 24VDC discrete signals and maps them into a single byte of input data (1 bit per channel). The module supports selectable input filter times from 0 to 65 ms with a 1 ms default for noise rejection.
Catalog Number Breakdown
| Code | Meaning | Value |
|---|---|---|
| 1734 | Platform | POINT I/O -- modular distributed I/O |
| I | Module type | Input |
| B | Signal type | DC sinking (B = DC sink; V = DC source) |
| 8 | Channel count | 8 discrete input points |
Key Specifications
| Parameter | Value |
|---|---|
| Number of Inputs | 8 (1 group of 8), sinking |
| Diagnostics | No (standard IB8 has no per-channel diagnostics) |
| Voltage, On-State (nominal) | 24V DC |
| Voltage, On-State (range) | 10 -- 28.8V DC |
| Voltage, Off-State (max) | 5V DC |
| Current, On-State (nominal) | 4 mA @ 24V DC |
| Current, On-State (range) | 2 mA -- 5 mA |
| Current, Off-State (min) | 1.5 mA |
| Impedance, Input (nominal) | 3.6 kΩ |
| Impedance, Input (max) | 4.7 kΩ |
| Input Filter Time | 0.5 ms hardware + (0 -- 65 ms selectable) -- Off-to-On and On-to-Off |
| POINTBus Current (max) | 75 mA @ 5V DC |
| Power Dissipation (max) | 1.6 W @ 28.8V DC |
| Thermal Dissipation (max) | 5.5 BTU/hr @ 28.8V DC |
| Isolation Voltage | 50V continuous, reinforced insulation. Type tested at 2500V DC for 60 s, field-side to system. |
| External DC Power Supply (nominal) | 24V DC @ 60 Hz |
| External DC Power Supply (range) | 10 -- 28.8V DC |
| Dimensions (H x W x D) | 56.6 x 12.1 x 77.5 mm (2.23 x 0.48 x 3.05 in.) |
| Weight | 32.3 g (1.14 oz) |
| Terminal Base | 1734-TB, 1734-TBS, 1734-TOP, or 1734-TOPS |
| Wiring Category | 1 -- on signal ports |
| Keyswitch Position | 1 |
| Operating Temperature | -20 to +55°C (-4 to +131°F) |
| Enclosure Type | None (open-style) |
| Hazardous Location | Class I Division 2, ATEX Zone 2, IECEx |
POINT I/O vs. Compact 5000
Unlike the Compact 5000 (5069) platform which connects directly to a CompactLogix controller via a local I/O bus, POINT I/O modules communicate through a separate network adapter (1734-AENT for EtherNet/IP, 1734-ACNR for ControlNet). This makes POINT I/O ideal for distributed I/O applications where modules are located away from the controller -- in remote panels, junction boxes, or machine-mounted enclosures.
2. Hardware Installation
The POINT I/O system uses a No Tools design. The terminal base mounts to a DIN rail, the I/O module snaps into the base, and the removable terminal block (RTB) clips onto the front for field wiring.
System Assembly Order
| Position | Module | Example |
|---|---|---|
| 1 (leftmost) | Communication Adapter | 1734-AENT (EtherNet/IP), 1734-ACNR (ControlNet), or 1734-ADN (DeviceNet) |
| 2 -- 17 | I/O Modules | 1734-IB8 in any available slot (up to 17 modules per adapter, max 10 A field power) |
| Optional | Expansion Power Supply | 1734-EPAC or 1734-EP24DC (if field power bus needs extending) |
Installation Steps
- Mount the terminal base on the DIN rail. Position the 1734-TB or 1734-TBS terminal base vertically above the rail. Hook the top rail clip, then press the bottom until the locking mechanism engages. The base interlocking side pieces connect to the adjacent base to form the POINTBus backplane.
- Set the keyswitch to position 1. Use a bladed screwdriver to rotate the keyswitch on the mounting base clockwise until the number 1 aligns with the notch. Verify the DIN rail locking screw is in the horizontal position.
- Slide the I/O module into the terminal base. Insert the module straight down into the mounting base and press to secure. The module locks into place and engages the POINTBus connector on the base automatically.
- Snap the RTB onto the module. Hook the RTB end into the base unit curved section, rotate the terminal block into the wiring base until it locks, then snap the RTB handle into place on the module. The RTB can be pre-wired at a bench before installation.
- Note the slot position. Modules are numbered left to right starting from slot 0 (immediately to the right of the communication adapter). Record the slot number for Studio 5000 configuration.
- Apply power. Connect 24V DC field power to the communication adapter's field power terminals. The POINTBus distributes backplane power to all modules.
Removal and Insertion Under Power (RIUP)
POINT I/O modules support Removal and Insertion Under Power (RIUP). You can insert or remove a module while the system is powered without causing a bus fault. However, the affected channel outputs will go to their configured fault state during the swap. When used in a Class I Division 2 hazardous location, ensure power is removed or the area is verified nonhazardous before connecting or disconnecting the RTB -- an electric arc can occur.
Terminal Block Options
The 1734-IB8 supports two types of terminal base assemblies:
| Terminal Base | Type | Description |
|---|---|---|
| 1734-TB / 1734-TBS | Two-piece (mounting base + RTB) | Screw-clamp (TB) or spring-clamp (TBS). RTB separates from the base for module replacement without rewiring. |
| 1734-TB3 / 1734-TB3S | Two-piece (3-wire, mounting base + RTB) | Screw-clamp (TB3) or spring-clamp (TB3S). 3-wire termination for proximity sensors. |
| 1734-TOP / 1734-TOPS | One-piece | Screw-clamp (TOP) or spring-clamp (TOPS). Terminal base and wiring in one unit. |
| 1734-TOP3 / 1734-TOP3S | One-piece (3-wire) | Screw-clamp (TOP3) or spring-clamp (TOP3S). One-piece with 3-wire termination. |
Terminal Block Removal
- Pull up on the RTB handle on the I/O module to unlatch it.
- Pull on the RTB handle to remove the RTB from the wiring base.
- To reinstall, hook the RTB end into the base unit, rotate until it locks, and snap the RTB handle into place.
For 1734-RTBS and 1734-RTB3S spring-clamp terminals, insert a bladed screwdriver (1492-N90, 3 mm diameter) into the opening at approximately 73° to latch and unlatch the wire. For 1734-TOPS and 1734-TOP3S, insert at approximately 97° and press in.
3. Wiring
Terminal Assignments
The 1734-IB8 has 8 terminal positions. On the 1734-TB and 1734-TBS bases, the terminals are arranged in a column. Field power (V = supply, C = common) is daisy-chained from the communication adapter, 1734-FPD field power distributor, 1734-EP24DC expansion power supply, or from a user-supplied external auxiliary terminal block.
| Pin | Function | Description |
|---|---|---|
| 0 | Input 0 | Channel 0 -- field device signal |
| 1 | Input 1 | Channel 1 -- field device signal |
| 2 | Input 2 | Channel 2 -- field device signal |
| 3 | Input 3 | Channel 3 -- field device signal |
| 4 | Input 4 | Channel 4 -- field device signal |
| 5 | Input 5 | Channel 5 -- field device signal |
| 6 | Input 6 | Channel 6 -- field device signal |
| 7 | Input 7 | Channel 7 -- field device signal |
All 8 terminals are independent input channels. Field power common/return and supply voltage are distributed through the POINTBus backplane from the communication adapter's V DC and DC COM terminals, not through the I/O module RTB pins. For 3-wire proximity sensors, use the 1734-TB3/TB3S or 1734-TOP3/TOP3S terminal bases which provide dedicated common (C) and voltage (V) terminals per channel pair.
Wire Specifications
| Parameter | Value |
|---|---|
| Wire Size | 0.25 -- 2.5 mm² (24 -- 14 AWG), 1 wire per cavity |
| Wire Size (18 AWG) | 0.75 mm², 2 wires per cavity (stranded only) |
| Strip Length (without ferrule) | 16 ± 1 mm (0.63 ± 0.03 in.) |
| Signal Terminal Voltage | 28.8V DC, 120/240V AC max |
| Signal Terminal Current | 2 A max |
| Terminal Base Screw Torque | 0.8 N·m (7 lb·in) |
Sink Wiring Configuration
For sink wiring (the standard configuration for the 1734-IB8), connect field devices as follows:
| From | To | Description |
|---|---|---|
| +24VDC field supply | Field device (one side) | Positive leg of field power supply |
| Field device (other side) | Module input terminal (pin 0 -- 7) | Signal wire to the input channel |
| DC COM (0V) | Communication adapter DC COM terminal | Return path via POINTBus backplane |
Typical Field Device Wiring Examples
| Field Device | Contact Type | Wiring | Notes |
|---|---|---|---|
| Pushbutton (Start) | Normally Open (NO) | +24V → PB → Input pin | Input ON when pressed |
| Pushbutton (Stop / E-Stop) | Normally Closed (NC) | +24V → PB → Input pin | Input ON normally; OFF when pressed (fail-safe) |
| 3-Wire PNP Proximity Sensor | PNP sourcing | +24V → BN; BK → Input pin; BU → 0V | PNP sensors recommended with sink inputs -- ON/OFF matches active/inactive |
| 2-Wire Proximity Sensor | 2-wire | +24V → sensor → Input pin | Sensor wires in series between supply and input; verify leakage current is below off-state threshold (1.5 mA) |
| Limit Switch | NO or NC | +24V → Switch → Input pin | Use NC for safety-critical applications |
| Overload Relay (95-96) | NC | +24V → 95 → 96 → Input pin | Input ON = normal; OFF = tripped (fail-safe) |
Field Power Distribution
The 1734-IB8 receives its field-side power through the POINTBus backplane, originating from the communication adapter's 24V DC field power terminals (10 -- 28.8V DC, 10 A max). All sink input modules share the common DC return through the backplane. You do not wire a separate power return to each I/O module -- only signal wires connect to the 8-pin RTB.
Field Power Budget
Each communication adapter supports a maximum of 10 A field power current across all modules on the bus. When planning your I/O configuration, total the field-side current draw of all modules. If the budget is exceeded, add an expansion power supply (1734-EPAC or 1734-EP24DC) to create a new field power segment.
4. Studio 5000 Configuration
POINT I/O modules are configured through the communication adapter in Studio 5000. The adapter appears in the I/O tree, and individual I/O modules are added as children of the adapter. This Series D product can be used with DeviceNet and PROFIBUS adapters, and with ControlNet and EtherNet/IP adapters using RSLogix 5000 software version 11 or later or Studio 5000 Logix Designer application version 20 or later.
Adding the Module to the I/O Tree
- In Studio 5000 Logix Designer, expand Controller Organizer → I/O Configuration → expand your EtherNet/IP network or ControlNet network → expand the 1734-AENT or 1734-ACNR adapter node.
- Right-click the adapter → New Module.
- In the module search dialog, type
1734-IB8and select it. Click Create. - Set the Name -- use a descriptive name such as
DI_Remote1. - Set the Slot number to match the physical position (Slot 0 = first module to the right of the adapter).
- Click OK. The module appears under the adapter in the I/O tree.
Connection Settings
| Setting | Options | Recommendation |
|---|---|---|
| RPI (Requested Packet Interval) | Direct Connection = 50 ms; Rack Optimization = not selectable | Default 50 ms for direct connection. For digital inputs where response time matters, keep at 50 ms or adjust based on application needs. |
| Connection Type | Data (default), Listen Only, Listen Only - Rack Optimization, Rack Optimization | Data (default) for most applications. Rack Optimization reduces network traffic by combining multiple modules into one connection. |
| Data Format | Integer | Integer is the only option for digital modules. |
Input Filter Configuration
The 1734-IB8 supports separate Off-to-On and On-to-Off input filter times for each channel. Open the Configuration tab in module properties to set filter values. Each input is independently settable in 1 ms increments.
| Feature | Description |
|---|---|
| Channel | Channels 0 through 7 -- each individually configurable |
| Input Filter Time (ms) | Off-to-On and On-to-Off transition filter constant. A high signal must be present for this duration before the module reports On. A low signal must be present for this duration before reporting Off. Default is 1 ms. The hardware imposes a fixed 0.5 ms minimum filter. |
Filter Time Recommendations
| Filter Time | Use Case |
|---|---|
| 0 ms (Off) | High-speed signals, externally debounced sensors |
| 1 ms (Default) | Clean electronic signals -- proximity sensors, photoelectric sensors |
| 5 -- 10 ms | General purpose -- good balance of speed and noise rejection |
| 10 -- 20 ms | Mechanical contacts -- limit switches, relay contacts |
| 20 -- 65 ms | Pushbuttons, toggle switches, very noisy environments |
Create Aliases for Readability
Always create alias tags for your I/O points. Right-click any I/O tag → New Tag → set the Type to Alias and point it to the I/O address. For example, alias
PB_Start to the input address. This makes your ladder logic self-documenting and simplifies maintenance.
5. Reading Inputs in Ladder Logic
Digital inputs from the 1734-IB8 are read using standard ladder logic instructions. The module produces 1 byte of input data -- 8 bits, one per channel.
Instructions
| Instruction | Name | Function |
|---|---|---|
| XIC | Examine If Closed | TRUE when the bit is 1 (input is ON). Equivalent to a normally open contact. |
| XIO | Examine If Open | TRUE when the bit is 0 (input is OFF). Equivalent to a normally closed contact. |
Data Map
The 1734-IB8 produces 1 byte of scanner Rx data. It does not consume any scanner Tx data.
| Direction | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
|---|---|---|---|---|---|---|---|---|
| Produce (scanner Rx) | Ch7 | Ch6 | Ch5 | Ch4 | Ch3 | Ch2 | Ch1 | Ch0 |
| Consume (scanner Tx) | No consumed data |
Where: Ch0 = Input channel 0, Ch1 = Input channel 1, ... Ch7 = Input channel 7. 0 = Off, 1 = On.
Practical Example: Motor Start/Stop with Safety Interlocks
This example shows a motor control circuit using the 1734-IB8 for inputs and a 1734-OB8 (8-point digital output in Slot 1) for outputs.
I/O Assignment Table
| Tag Alias | I/O Address | Module | Field Device | Contact Type |
|---|---|---|---|---|
| PB_Start | Adapter:0:I.Data.0 | 1734-IB8 Slot 0 | Green pushbutton | NO momentary |
| PB_Stop | Adapter:0:I.Data.1 | 1734-IB8 Slot 0 | Red pushbutton | NC momentary (wired NC) |
| EStop_OK | Adapter:0:I.Data.2 | 1734-IB8 Slot 0 | E-Stop mushroom head | NC (fail-safe) |
| OL_OK | Adapter:0:I.Data.3 | 1734-IB8 Slot 0 | Overload relay (95-96) | NC (opens on trip) |
| Motor_Run | Adapter:1:O.Data.0 | 1734-OB8 Slot 1 | Motor contactor coil | 24VDC coil |
| Pilot_Run | Adapter:1:O.Data.1 | 1734-OB8 Slot 1 | Green pilot light | 24VDC LED |
| Pilot_Fault | Adapter:1:O.Data.2 | 1734-OB8 Slot 1 | Red pilot light | 24VDC LED |
Ladder Logic (Structured Text Representation)
// ── Motor_1 Control Routine ─────────────────────────────────
// Module: 1734-IB8 in Slot 0 (inputs), 1734-OB8 in Slot 1 (outputs)
// Adapter: 1734-AENT EtherNet/IP adapter
//
// Tag Aliases:
// PB_Start → Adapter:0:I.Data.0 (NO momentary pushbutton)
// PB_Stop → Adapter:0:I.Data.1 (NC momentary -- wired NC, ON = normal)
// EStop_OK → Adapter:0:I.Data.2 (NC E-Stop -- wired NC, ON = normal)
// OL_OK → Adapter:0:I.Data.3 (NC overload relay, ON = normal)
// Motor_Run → Adapter:1:O.Data.0 (Motor contactor coil)
// Pilot_Run → Adapter:1:O.Data.1 (Green run indicator)
// Pilot_Fault→ Adapter:1:O.Data.2 (Red fault indicator)
// ─────────────────────────────────────────────────────────────
// Rung 1 -- Start/Stop seal-in with safety interlocks
IF (PB_Start OR Motor_Run) AND PB_Stop AND EStop_OK AND OL_OK AND NOT Motor_Fault THEN
Motor_Run := 1;
ELSE
Motor_Run := 0;
END_IF;
// Rung 2 -- Fault latch
IF Motor_Run AND NOT OL_OK THEN
Motor_Fault := 1;
END_IF;
// Rung 3 -- Fault reset
IF PB_FaultReset AND OL_OK AND EStop_OK THEN
Motor_Fault := 0;
END_IF;
// Rung 4 -- Pilot lights
Pilot_Run := Motor_Run;
Pilot_Fault := Motor_Fault;
NC Wiring and XIC Logic
The Stop pushbutton, E-Stop, and overload relay are all wired with normally closed contacts. In their normal (safe) state, the input reads ON (1). The ladder logic uses XIC for these -- TRUE when normal. If a wire breaks or the E-Stop is pressed, the input goes OFF, breaking the seal-in rung. This is the standard fail-safe pattern.
6. Diagnostics & Troubleshooting
LED Indicators
The 1734-IB8 has Module Status, Network Status, and 4 I/O channel status LEDs. The 4 I/O LEDs each represent two channels: LED 0 = Ch 0 & 4, LED 1 = Ch 1 & 5, LED 2 = Ch 2 & 6, LED 3 = Ch 3 & 7.
Module Status LED
| LED | Color | State | Meaning |
|---|---|---|---|
| Module Status | Off | No Power | No power is applied to the device. Apply power. |
| Module Status | Steady green | Normal | The device is operating normally. |
| Module Status | Flashing green | Standby | The device needs commissioning due to missing, incomplete, or incorrect configuration. |
| Module Status | Flashing red | Recoverable Fault | A recoverable fault is present. 1. Cycle power. 2. If condition persists, replace the device. |
| Module Status | Steady red | Unrecoverable Fault | An unrecoverable fault occurred that may require device replacement. |
| Module Status | Flashing red/green | Self-Test | The device is in self-test mode. No action required. |
Network Status LED
| LED | Color | State | Meaning |
|---|---|---|---|
| Network Status | Off | Offline | The device is not online, has not completed dup_MAC_id test, or is not powered. |
| Network Status | Flashing green | No Connections | The device is online but has no connections in the established state. |
| Network Status | Steady green | Connected | The device is online and has connections in the established state. |
| Network Status | Flashing red | Timed Out | One or more I/O connections are in a timed-out state. Check for I/O module failure. |
| Network Status | Steady red | Communication Failure | Critical link failure. The device has detected an error preventing communication. |
| Network Status | Flashing red/green | Communication Faulted | The device has detected a network access error and is in a communication faulted state. |
I/O Channel Status LEDs
| LED | Color | State | Meaning |
|---|---|---|---|
| I/O Status (per pair) | Off | Input Off | Both paired channels are in the Off state. |
| I/O Status (per pair) | Yellow | Input On | One or both of the paired channels is in the On state. |
The 4 I/O LEDs each represent two channels: LED 0 = Ch 0 & 4, LED 1 = Ch 1 & 5, LED 2 = Ch 2 & 6, LED 3 = Ch 3 & 7. A LED lights yellow if either of its paired channels is On.
Common Faults and Resolutions
| Symptom | Likely Cause | Resolution |
|---|---|---|
| Module Status flashing green | Configuration missing or incomplete | Verify the module is added to the I/O tree in Studio 5000 with the correct slot number. Download the project. |
| Network Status off | Device not on the network | Check that the communication adapter is powered and online. Verify the terminal bases are properly seated and the POINTBus backplane is continuous. |
| Network Status flashing red | I/O connection timed out | Check the module is properly seated in its terminal base. Verify the RPI and connection type in Studio 5000. |
| Input LED is yellow but tag reads 0 | Module inhibited or project not downloaded | Right-click module in I/O tree → Properties → Connection tab → verify "Inhibit Module" is unchecked. Re-download the project. |
| Input LED is off but field device is activated | Wiring fault | Check field wiring: verify 24VDC at the field device output, check for broken wires, measure voltage at the input terminal (should be >10V when ON). |
| All 8 inputs read 0 | No field power | Verify 24VDC is connected to the communication adapter's field power terminals and the POINTBus is distributing power. |
| Input chatters ON/OFF rapidly | Electrical noise or contact bounce | Increase the input filter time for that channel. For mechanical contacts, try 10 -- 20 ms. Check cable routing and shielding. |
Electronic Keying
Studio 5000 supports electronic keying for POINT I/O modules. By default, Compatible Module keying is used -- the physical module must match the configured catalog number but allows minor revision differences. If you replace a module with a different series or revision, check the keying settings in module properties.
Automatic Device Replacement
POINT I/O supports Automatic Device Replacement. When a failed module is replaced with a new one of the same type, the adapter automatically downloads the configuration to the replacement module. The new module begins operation without requiring a project download from Studio 5000.
7. Related POINT I/O Digital Input Modules
The POINT I/O platform includes several digital input module variants:
| Catalog Number | Channels | Type | Key Difference | Typical Application |
|---|---|---|---|---|
| 1734-IB2 | 2 | 24VDC Sink | 2 inputs in compact form | Low-density applications, small machine I/O |
| 1734-IB4 | 4 | 24VDC Sink | 4 inputs | Mid-density applications |
| 1734-IB4K | 4 | 24VDC Sink (Conformal Coated) | Same as IB4 with conformal coating | Harsh environments |
| 1734-IB8 | 8 | 24VDC Sink | Standard 8-point -- this guide | General purpose distributed I/O |
| 1734-IB8K | 8 | 24VDC Sink (Conformal Coated) | Same as IB8 with conformal coating | High humidity, corrosive atmospheres |
| 1734-IB4D | 4 | 24VDC Sink with Diagnostics | Per-channel open wire and short circuit detection | Applications requiring field-side diagnostics |
| 1734-IV2 | 2 | 24VDC Source | Sourcing input variant | Sourcing sensor applications |
| 1734-IV4 | 4 | 24VDC Source | 4 sourcing inputs | Mid-density sourcing |
| 1734-IV8 | 8 | 24VDC Source | 8 sourcing inputs | High-density sourcing |
8. Related Guides
| Guide | Description |
|---|---|
| CompactLogix 5069-L306ER Setup Guide | First-time setup for the CompactLogix 5380 controller -- power wiring, Studio 5000 project creation, and network setup. |
| 5069-IB16 Digital Input Module Guide | Installation, wiring, and programming for the 16-channel Compact 5000 digital input module -- the local I/O equivalent of the 1734-IB8. |
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 |
|---|---|---|
| 1734-UM001 | POINT I/O Digital and Analog Modules and POINTBlock I/O Modules User Manual | |
| 1734-IN051 | POINT I/O Input Modules Installation Instructions | |
| 1734-SG001 | POINT I/O Modules Selection Guide |
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