1746-HSTP1/E Buyer’s Guide: Replacing a Discontinued SLC 500 Stepper Controller
Finding a reliable source for the 1746-HSTP1/E has become a real challenge since Allen-Bradley discontinued this module on January 31, 2017. If your SLC 500 line depends on single-axis stepper motion, you need a clear path forward — either verified legacy stock or a documented direct replacement. This buyer’s guide helps you evaluate both options against your actual machine requirements.
What This Module Does
The 1746-HSTP1/E is a single-axis open-loop stepper motor controller module for the Allen-Bradley SLC 500 platform, part of the Bulletin 1746 family. It generates high-speed pulse trains that drive stepper drives or pulse-mode servo drives. The module supports a programmable velocity up to 250 kHz and an absolute position range of ±8,388,607 counts. Output modes include pulse+direction or CW/CCW, giving you flexibility across different drive vendors. You configure and command the module through RSLogix 500 ladder logic, so existing SLC 500 programs remain the control interface.
Key Specifications at a Glance
| Parameter | Value |
|---|---|
| Product Type | Stepper Motor Controller Module |
| Axes | Single-axis, open-loop |
| Max Pulse Rate | 250 kHz |
| Position Range | ±8,388,607 pulses |
| Output Modes | Pulse+direction or CW/CCW |
| Backplane Current | 200 mA @ 5V DC, 90 mA @ 24V DC |
| Inputs | Home, limit, and E-stop |
| Configuration | RSLogix 500 ladder logic |
Why the 250 kHz Rate Matters
The 250 kHz pulse rate determines how fast your axis can move without losing step resolution. Higher rates let you run finer microstepping at production speed. The ±8,388,607-count range gives you generous absolute positioning headroom for long-travel applications. The dedicated home, limit, and E-stop inputs simplify machine safety and referencing logic, reducing the ladder code you need to write.
Where This Module Fits
Three scenarios come up most often with the 1746-HSTP1/E:
- Packaging and labeling lines — indexing conveyors and registration axes that need repeatable single-axis motion at speed.
- Retrofit projects — existing SLC 500 racks where replacing the whole control platform is not economically justified.
- Legacy CNC and positioning tables — machines with pulse-mode drives already wired and programmed.
Installation and Setup Notes
The module is not hot-swappable. Never install, remove, or wire it with power applied. The 1746 chassis backplane supplies 5.1V DC @ 10A and 24V DC @ 2.88A to all modules, but field-side load power requires an external supply. Slot 0 stays reserved for the processor or a 1747-ASB adapter. Removable terminal blocks simplify field wiring, and Bulletin 1492 pre-wired interface cables are available for faster commissioning.
Compatibility and Integration
The 1746-HSTP1/E mounts in any 1746 chassis — the 1746-A4, -A7, -A10, or -A13 — all panel-mount designs with 4, 7, 10, or 13 slots. It works with SLC 500 processors and integrates through RSLogix 500. Because the module outputs standard pulse+direction or CW/CCW signals, it can drive a range of stepper and pulse-mode servo drives, not just Allen-Bradley units.
Replacement Path: AMCI 3501-HSTP1
Rockwell lists the AMCI 3501-HSTP1 as a direct replacement under the Encompass program. That means pinout and functional compatibility are documented, which shortens migration time. If you choose this route, verify your drive wiring and revalidate motion parameters after the swap. If you prefer to keep identical hardware, SpareTechPLC can help you source tested legacy 1746-HSTP1/E stock.
What to Verify Before You Buy
- Confirm your chassis model and available slot count.
- Check that your drive accepts pulse+direction or CW/CCW input.
- Confirm backplane current budget: 200 mA at 5V DC and 90 mA at 24V DC per module.
- Decide between legacy stock and the AMCI 3501-HSTP1 replacement.
- Verify current lifecycle status and availability with SpareTechPLC before ordering.
Maintenance and Reliability
Inspect terminal blocks and wiring periodically for looseness or corrosion. Keep the enclosure within the family operating range of 0 to 60 C and 5-95% RH non-condensing. Because the module is discontinued, keeping a spare on the shelf protects you against unplanned downtime. For safety-related functions, follow the manufacturer’s safety manual and inspect the E-stop and limit input circuits at regular intervals.
FAQs
Is the 1746-HSTP1/E still in production?
No. Allen-Bradley discontinued it on January 31, 2017. You can still find tested legacy stock, or use the AMCI 3501-HSTP1 direct replacement.
Can I replace it without rewriting my program?
The AMCI 3501-HSTP1 is listed as a direct replacement, so your RSLogix 500 logic should transfer. Always revalidate motion parameters after installation.
What drives can it control?
It drives stepper drives and pulse-mode servo drives that accept pulse+direction or CW/CCW signals.
How much backplane current does it draw?
200 mA at 5V DC and 90 mA at 24V DC.
Is it hot-swappable?
No. Never install, remove, or wire the module with power applied.
