User manual

Chapter 1 Introduction to the 2762-17

ADVANCED MICRO CONTROLS INC.

AMCI Compatible Transducers

The 2762-17 is compatible with the following NEMA 4 transducers manufactured by

AMCI.

HTT-20-100: 100 turn absolute position transducer

HTT-20-180: 180 turn absolute position transducer

HTT-20-1000: 1,000 turn absolute position transducer

HTT-20-1800: 1,800 turn absolute position transducer

Each transducer contains two resolvers. The first resolver, called the fine resolver, is

attached with a flexible coupler directly to the shaft. The second resolver, called the coarse

resolver, is geared to the fine. This gear ratio, either 99:100 or 179:180 determines the total

number of turns the transducer can encode.

At the mechanical zero of the transducer the electrical zeros of the two resolvers are aligned.

See Figure 1.4A. After one complete rotation, the zero of the coarse resolver lags behind the

zero of the fine by one tooth, either 1/100 or 1/180 of a turn. After two rotations the lag is

2/100 or 2/180. See Figures 1.4B and 1.4C. After 100 or 180 turns, the electrical zeros of the

resolvers are realigned and the multiturn cycle begins again.

The 2762-17 simultaneously reads the resolvers every 800 µSec. The fine resolver yields the

absolute position within the turn directly. Using a proprietary algorithm, the 2762-17

determines the number of turns completed by the difference in positions of the two resolvers.

The absolute multiturn position is then calculated as ((number of turns completed * counts per

turn) + fine resolver position).

The 1,000 and 1,800 turn transducers have an additional 10:1 gear ratio between the input

shaft and the fine resolver. Therefore they can encode ten times the number of turns but at a

tenth of the resolution.

To the 2762-17 module, the 1,000 and 1,800 turn transducers appear to be 100

or 180 turn transducers. Therefore only 100 and 180 turn transducers are

discussed in this manual.

FINE

COURSE FINE

COURSE

Mechanical Zero

After One Turn

After Two Turns

Figure 1.4 Resolver Alignment in Multiturn Transducers