Why Maintenance Teams Still Rely on the 1746-HSTP1/E
From a maintenance engineer’s viewpoint, the hardest part of keeping a legacy SLC 500 line running is not the processor — it is the motion axis that nobody wants to re-engineer. The Allen-Bradley 1746-HSTP1/E solves that problem as a single-axis open-loop stepper motor controller module that generates high-speed pulse trains for stepper or pulse-mode servo drives. Because it is configured and commanded through RSLogix 500 ladder logic, your existing program, wiring drawings, and troubleshooting routines stay valid.
Rockwell Automation lists this module as discontinued with a discontinuation date of 2017-01-31, and it names a direct replacement: the AMCI 3501-HSTP1 per Rockwell Encompass. That combination — a known end-of-life date plus a documented drop-in path — is exactly what makes the 1746-HSTP1/E a predictable service part rather than a surprise.
Key Specifications That Drive Uptime
For a maintenance engineer, three numbers on this module decide whether an axis can be repaired in place or must be redesigned. The 1746-HSTP1/E supports a programmable velocity up to 250 kHz, an absolute position range of ±8,388,607 counts, and output modes of pulse+direction or CW/CCW. Those three parameters cover the majority of indexing, feed-to-length, and positioning moves found on older SLC 500 equipment.
Backplane current draw is modest: 200 mA at 5V DC and 90 mA at 24V DC. That low logic-side demand means the module rarely stresses the chassis power budget, which matters when you are adding or swapping modules in a panel that is already fully populated.
| Parameter | Value |
|---|---|
| Axis count | Single-axis stepper control |
| Position range | ±8,388,607 pulses |
| Max velocity | Up to 250 kHz |
| Output modes | Pulse+direction or CW/CCW |
| Backplane current | 200 mA @ 5V DC, 90 mA @ 24V DC |
| Dedicated inputs | Home / limit / estop |
Built for Serviceability in the Field
The 1746-HSTP1/E mounts in a 1746 chassis — 1746-A4, -A7, -A10, or -A13 — with 4, 7, 10, or 13 slots, and all of those chassis are panel-mount. Field wiring lands on removable terminal blocks, and a Bulletin 1492 pre-wired interface is available, so a technician can pre-build a replacement harness instead of terminating wires live in a crowded enclosure.
One safety point deserves emphasis for anyone doing this work: the module is not hot-swappable. Do not install, remove, or wire it with power applied. Also remember that slot 0 stays reserved for the processor or a 1747-ASB adapter, so plan the physical position of the replacement before you pull the old module.
Where This Module Earns Its Keep
In a typical packaging line application, a single 1746-HSTP1/E might drive a stepper motor that indexes a film-feed roller to a registration mark, using the home and limit inputs to re-zero the axis each cycle. In a typical cut-to-length application, the same module commands a pulse-mode servo drive through pulse+direction output, holding position within the ±8,388,607 count range while the line runs at production speed. These are realistic illustrations of how the module is used, not claims about a specific customer installation.
Because the module is configured in RSLogix 500 ladder logic, a maintenance team that already owns the SLC 500 program can restore an axis without rewriting motion code. That single fact often decides whether a line returns to service in hours or in days.
Replacement Path and Business Value
The documented replacement for the 1746-HSTP1/E is the AMCI 3501-HSTP1 per Rockwell Encompass. For a plant running SLC 500 equipment, that means a failed axis does not automatically trigger a controller migration project. You can keep the existing chassis, backplane, and ladder logic in place and address the failure at the module level.
From a cost standpoint, the value is straightforward: avoiding an unplanned controller upgrade protects capital budget, and keeping a spare 1746-HSTP1/E on the shelf protects production schedule. The module’s low backplane draw of 200 mA at 5V DC and 90 mA at 24V DC also means it can be stocked and swapped without recalculating panel power.
Supply Assurance from SpareTechPLC
SpareTechPLC specializes in industrial automation spare parts, including discontinued Allen-Bradley SLC 500 modules like the 1746-HSTP1/E. Our team verifies part numbers and series suffixes before shipment so that what arrives matches what your drawings call for. If you need to confirm a replacement path or check stock, contact us with your part number and application details.
Frequently Asked Questions
Is the 1746-HSTP1/E still available?
Rockwell Automation lists the 1746-HSTP1/E as discontinued with a discontinuation date of 2017-01-31. Availability therefore depends on remaining stock and the secondary market. Contact SpareTechPLC to confirm current inventory for this part number.
What replaces the 1746-HSTP1/E?
The documented replacement is the AMCI 3501-HSTP1 per Rockwell Encompass, described as a direct replacement. Please refer to the official Allen-Bradley documentation or contact SpareTechPLC for specific details on your application.
Can I hot-swap the 1746-HSTP1/E during production?
No. The module is not hot-swappable. Do not install, remove, or wire it with power applied. Isolate power first, then follow your plant’s lockout procedures before touching the module or its terminal blocks.
Which chassis slots can hold the 1746-HSTP1/E?
The module mounts in a 1746 chassis — 1746-A4, -A7, -A10, or -A13 — with 4, 7, 10, or 13 slots, all panel-mount. Slot 0 is reserved for the processor or a 1747-ASB adapter, so the module must go in another slot.
What output modes does the 1746-HSTP1/E support?
It supports pulse+direction or CW/CCW output modes, with a programmable velocity up to 250 kHz and an absolute position range of ±8,388,607 counts. It also provides home, limit, and estop inputs for axis control.
