Reliance 45C959 16-Channel 120 VAC Relay Output Module

Description

Key Technical Specifications

Rockwell’s Shark XL II manual lists 45C959 among the platform’s digital output modules and specifies it as a 16-channel relay output with removable terminal block. The manual also confirms that channels 0–7 use C1 and channels 8–15 use C2, with C1 and C2 not internally connected.

A separate technical listing reports the module’s relay application as 120 VAC, 2 A, 50/60 Hz. It also identifies the 16 individual LED indicators and the separate C1/C2 commons.

Product Introduction

The Reliance Electric 45C959 is a 16-point digital relay output module for the Shark XL programmable controller family. Each channel provides relay switching, with channels 0–7 referenced to common C1 and channels 8–15 referenced to common C2. The module uses a removable terminal block and provides an individual status LED for each output.

This module is relevant when maintaining legacy Reliance Electric Shark XL installations where the existing I/O architecture must remain unchanged. The most important replacement checks are output voltage, load current, terminal arrangement, and the C1/C2 grouping. Do not substitute a transistor-output module merely because the channel count matches.

Installation & Configuration Guide

Stage 1: Pre-Installation Preparation

Estimated time: 15–30 minutes

⚠️ Safety First: Stop the controlled equipment and place the PLC system in its approved maintenance state. Apply LOTO to external field power feeding the output loads. Verify absence of hazardous voltage before disconnecting the module.

Tools Required:

• ESD wrist strap
• Digital multimeter
• Insulated screwdriver
• Wire labels
• Smartphone/camera
• Terminal screwdriver

Data Backup:

1. Record the exact module number: 45C959.
2. Photograph the complete terminal block.
3. Photograph the LED/channel numbering.
4. Record which loads are connected to channels 0–15.
5. Identify which circuits use C1 and which use C2.
6. Record external fuse and circuit-breaker ratings.
7. Confirm the PLC program remains backed up.

Stage 2: Removing the Old Module

Estimated time: 10–20 minutes

1. Verify the PLC and field circuits are de-energized.
2. Confirm zero voltage at the output terminal block.
3. Label each field conductor before removal.
4. Record the common connection associated with each group.
5. Disconnect the removable terminal block.
6. Release the module retention mechanism.
7. Pull the module straight out of the rack.
8. Inspect the rack connector for bent contacts, contamination, or mechanical damage.

⚠️ Do not assume that a disconnected PLC rack means the field circuits are dead. External output power can remain present at the terminal block.

Stage 3: Installing the 45C959

Estimated time: 10–20 minutes

1. Verify the replacement is marked 45C959.
2. Inspect the PCB, terminal connector, housing, and LED window.
3. Confirm the replacement uses the same removable terminal arrangement.
4. Insert the module into the correct Shark XL rack position.
5. Seat it fully into the backplane connector.
6. Secure the module’s retention hardware.
7. Reinstall the terminal block.
8. Confirm each conductor is in the original channel.
9. Verify C1 and C2 connections.
10. Tighten terminals to the applicable equipment specification.

Self-Checklist:

• 45C959 verified
• Correct rack slot verified
• Terminal block fully seated
• Channels 0–7 checked
• Channels 8–15 checked
• C1 connection checked
• C2 connection checked
• Field wiring secured

Stage 4: Power-On & Testing

Estimated time: 20–45 minutes

1. Energize the PLC rack without enabling hazardous machine motion.
2. Confirm the module initializes normally.
3. Verify the 16 status LEDs are available.
4. Monitor the PLC diagnostic/status information.
5. Force or command one output at a time under controlled conditions.
6. Confirm the corresponding LED illuminates.
7. Verify the correct field device operates.
8. Test channels 0–7 and channels 8–15 separately.
9. Check output voltage under load.
10. Verify relay operation without excessive contact chatter.
11. Remove all test forces.
12. Return the PLC to normal control.
13. Perform a complete machine functional test.

⚠️ Do not leave PLC outputs forced after commissioning. A forgotten force can create an unexpected machine command during the next operating cycle.

45C959

45C959

Frequently Asked Questions (FAQ)

What is Reliance Electric 45C959?

The 45C959 is a 16-channel relay output module for the Reliance Electric Shark XL programmable controller family. Rockwell’s Shark XL II documentation explicitly lists 45C959 as a 16-channel relay output module with a removable terminal block.

What voltage can the 45C959 switch?

The commonly documented configuration is 120 VAC relay output at 2 A, while technical listings also identify application-dependent operating ranges covering 85–264 VAC and 21–27 VDC. Verify the actual load and external circuit arrangement against the installed system documentation before applying a replacement.

Are C1 and C2 internally connected?

No. Channels 0–7 use C1 and channels 8–15 use C2, and the two commons are not internally connected. This matters when the two output groups use different external supplies or circuit references.

Is 45C959 a transistor output module?

No. It is a relay-output module. That distinction matters when switching AC loads, inductive loads, or applications requiring electrical isolation characteristics associated with relay contacts.

Is the 45C959 discontinued?

Current industrial inventory records identify the part as discontinued by the manufacturer. It remains available through secondary-market suppliers in new-surplus, used, and refurbished conditions.

Can I replace it with another 16-point Shark XL output module?

Not automatically. The Shark XL family includes several 16-point output modules with different electrical characteristics. Rockwell’s documentation lists 45C959 alongside modules such as 45C961, 45C963, 45C964, and 45C965. Matching the channel count alone is insufficient.

Will replacing the 45C959 erase the PLC program?

No. The 45C959 is an I/O module, not the PLC processor or program-storage device. Replacing the output module should not by itself erase the controller program. The correct procedure is still to maintain a current PLC backup before performing maintenance.

What should procurement verify?

Specify Reliance Electric 45C959 and confirm:

• 16-channel relay output
• Removable terminal block
• 120 VAC / 2 A application
• C1/C2 common arrangement
• Shark XL compatibility
• Actual condition
• Test status
• Warranty
• Complete nameplate and revision photographs

For a legacy Shark XL installation, these details are more useful than simply requesting a “16-point output module.”