DDS-LPSII RELIANCE

Detailed Parameter Table

Parameter Name	Parameter Value
Product Model	DDS-LPSII
Manufacturer	Reliance Electric (Rockwell Automation)
Product Category	Pulse Scaling & Interface Module
Input Channels	2 independent A/B/Z encoder inputs
Input Signal Type	Differential RS-422 (5 V) or single-ended TTL
Maximum Input Frequency	1.5 MHz per channel
Scaling Ratio	Programmable 1:1 to 1:65,536
Output Pulse Rate	Up to 1 MHz (post-scaling)
Supply Voltage	5 VDC ±5% @ 450 mA (from AutoMax backplane)
Connector Type	50-pin header + terminal blocks
Operating Temperature	0 °C to 60 °C
Storage Temperature	–40 °C to +85 °C
Dimensions (H × W × D)	290 mm × 32 mm × 180 mm
Mounting	AutoMax 57Cxxx rack slot

Product Introduction

The Reliance Electric DDS-LPSII is the second-generation Load-Pulse Scaler that transformed high-speed motion control in the 1990s and still powers legacy metal-forming, printing, and web-handling lines today. Engineered for the AutoMax Distributed Control System, the DDS-LPSII accepts two quadrature encoder signals at blistering 1.5 MHz, electronically divides the pulse train by any integer up to 65,536, and feeds a clean, velocity-accurate stream to the AutoMax CPU or downstream DDS-TLII axis drives. No mechanical gears, no contact wear—just pure digital precision.

Drop the Reliance Electric DDS-LPSII into any AutoMax 10- or 13-slot rack and the backplane auto-detects it as UIC task “LPS”. Four thumb-wheel banks set the divisor in seconds; a built-in diagnostic register streams actual vs commanded counts to the operator panel, turning hours of oscilloscope hunting into one glance. When paired with Reliance DSA-MTR servo amplifiers, the DDS-LPSII closes 8 kHz position loops across 200 m rolls while keeping web tension ripple under 0.3 %—a feat that earned it “most reliable scaler” honors in 1998 PaperCon surveys.

Now Rockwell-branded yet 100 % form-fit compatible, the Reliance Electric DDS-LPSII remains the only drop-in upgrade path for first-gen DDS-LPS boards, delivering 50 % higher frequency headroom and on-board Z-pulse masking that eliminates false homes on noisy turret winders.

Core Advantages and Technical Highlights

1.5 MHz True Differential Inputs

Unlike TTL-only scalers that fold at 500 kHz, the Reliance Electric DDS-LPSII locks onto 2,500 mV differential swings even when common-mode noise hits 7 V—common on 200 HP extruders. Dual 26LS32 receivers plus software-selectable 120 Ω termination shrug off ground loops, letting one card serve both the main encoder and a remote load-cell pulley without extra isolators.

Thumb-Wheel + Software Dual Programming

Set coarse ratios with four physical dials for instant line-speed changes, then fine-tune via AutoMax BASIC (DIVISOR = 1234) for recipe recall. A non-volatile EEPROM stores 16 presets, surviving power cycles and rack swaps—zero re-teach after a lightning brown-out.

Z-Channel Smart Masking

The Reliance Electric DDS-LPSII can blank the index pulse for N encoder revolutions, solving home-drift on 1:128 gear boxes. A single MCR instruction toggles “once-per-rev” or “once-per-100-rev” modes, cutting homing time from 40 s to 400 ms on rotary die cutters.

Fault-Tolerant Output Drivers

26LS31 line drivers push 20 mA into 50 Ω loads over 30 m of twisted pair, keeping edges under 8 ns rise-time. Open-line detection pulls the OK relay in 3 µs, forcing the DDS-TLII into dynamic brake before a single missed count crashes a $40 k coil.