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M1151 Multi-Turn Decoder

M1151 Multi-Turn Decoder: 5 PLS Outputs
SAC-M1151-M10A x 0

  • Fully absolute position: no loss of position under power loss
  • Multi-turn (dual) resolver at position sensor
  • Programmable gear ration L (4, 8,16, 32, 64, 128, or 256:1 gear ratio)
  • Fall-safe broken resolver cable fault output
  • Motion output
  • Ideal for shut-height Indication on process
  • Very easy to calibrate - no calculations required
  • Fail-safe upper and lower safety limits switch outputs
  • Three general programmable llmltswitch outputs may be used as in-position output


The M1151-M10A is a multi-turn programmable decoder. It takes the input from a multi-turn resolver like Autotech's series RL210 which is mounted on the shaft of the rotating machinery. The M1151-M10A decodes the resolver signals using a highly noise immune ratiometric decoding technique, scales the digital data based on the programmed scale factor and displays it on the
front panel. The position information is also made available to the output port in BCD format for connecting to a remote display or a PLC. In each of the three PLS channels, the position information is continuously compared to two programmable on and off limits called "setpoints." The outputs are activated when limit conditions are satisfied. All outputs of the M1151-M10A are optically isolated and the resolver inputs are differential. ensuring extremely reliable operation of the unit even in the harshest of industrial conditions.

The M1151-M10A will decode the shaft angle to 1 /4096th of a revolution (12 bits) and runs up to gear ratio. The decoder also features motion detection, three channels of PLS outputs, two safety limit outputs, and PLC synchronization/handshaking for the BCD outputs, upper and lower safety limits to outputs.

Simple Front Panel Programming

The M1151-M10A is fully front panel programmable for all variables and yet secure against any unauthorized program changes. Opening of an extemal user provided keyswitch inhibits any program changes on the front panel.

No Batteries, No nvolatile Memory

Non-volatile EEROM memory retains information indefinitely after power loss or machine shutdown, eliminating batteries and related hazards.

Replacing Electromechanical Selsyo Systems

In new installations, the M1151-M10A together with Autotech's brushless resolver series RL210 is a 100% solid -state replacement for electromechanical Selsyn Systems.

PC Handshake for PLC Synchroni2ation

On an external data transfer command from a programmable controller, the digital shaft angle position can be "frozen " at the input of the PC in order to ensure that the data is not sampled during transition from one angle to the next and that the PLC always reads valid data.

Reliable Under Extreme Environments

The M1151-M10A combines the ruggedness of a brushless resolver and reliability of a solid-state control. The resolver can be mounted on a machine shaft in hostile environments such as mechanical shock, vibrations, extreme humidity and temperature changes, oil mists, coolants, solvents, etc., and the programmable unit M1151-M10A can be mounted up to 250 feet away in a control panel. The ratiometric converter assures high tracking speed and high noise immunity.

Self Diagnostics with Healthy Output

The M1151-M10A is provided with an internal self-check circuit that continuously monitors if the microprocessor is not in reset, input 120 VAC power, DC power supplies, resolver cable and output enable circuit. In case a fault occurs in any one of the above critical functions, the unit goes into fault mode and a transistor output changes state from ON to OFF. For fail-safe operation, the healthy output is ON for normal operation and turns OFF when a fault occurs.

Built in Motion Detector

Motion detector output and indicator LED is energized when the shaft is rotating in excess of 5 RPM . While the shaft is turning at less than 5 RPM or is stopped, die motion output and indicator LED may occasionally pulse on for a moment and then retum to the off state.

Ideal Solution for Shut Height Indication.

The M1151-M10A. along with a dual resolver, provides an ideal solution for shut-height indication. Because of absolute nature of the resolver, the position is retained even during powerloss.