MDT (M) Module (RMC150)

The MDT module for the RMC150 interfaces to Magnetostrictive Displacement Transducers (MDTs). These absolute-position transducers are especially well suited for hydraulic applications because of their non-contact design, robustness, modularity, and resistance to contaminants. The RMC150 MDT module supports transducers with Start/Stop and Pulse Width Modulated (PWM) outputs. The RMC150 can be configured to trigger from the rising or falling edges on Start/Stop transducers. MDTs with SSI output are supported by the RMC150 SSI Module.

See the MDT Fundamentals topic for details on how MDT feedback works.

Features

Two axes of MDT feedback per module
Up to 0.001” resolution using Start/Stop
Up to 0.0001” resolution using PWM with multiple recirculations
Supports internal transducer recirculations
Transducer length up to 398 inches (10.1 m) (4 ms loop time)
Differential (recommended) or single-ended interface
Two isolated, ±10 V, 12-bit control outputs per module
Current output up to ±200 mA with VC2124 converter option

Part Number

The part number of the MDT module is Mn, where n is the number of MDT modules.

For example, RMC150E-M1 is an RMC150E with one MDT module. RMC150E-M3-Q1 is an RMC150E with three MDT modules and one Quadrature module.

Supported Transducers

The following tables summarize the major transducer options supported by the MDT module:

MDT Options	Value
Types	Start/Stop (S/S) Pulse-Width-Modulated (PWM)
Count Range	32 bits
Wiring	Differential, 5 V, RS-422, Single-ended 5 V
Interrogation Modes	External. Notice that internal interrogation is not supported.
MDT Count Rate	120 MHz

Blanking Period

The RMC150 has a blanking period options of 5 µsec (default) and 21 µsec. Some older transducers, such as Temposonics I and II with neuter outputs, require the longer blanking period. For more details, see the MDT Fundamentals and MDT Blanking Period topics.

Setting Up the MDT Module

To set up the MDT module, read the following topics:

MDT Wiring

MDT Scaling

Specifications

For general specifications on the RMC150, see the RMC150 Overview topic.

General
Weight	74 g + 16 g (stock connectors)
MDT Interface
Axes	Two per module
Inputs	Two RS-422 differential (can also be used single-ended)
Outputs	Two RS-422 differential (can also be used single-ended)
ESD Protection	15 kV
Resolution	0.001 (25.4 µm) in Start/Stop; 0.0001 in (2.54 µm) PWM
Count Rate	120 MHz
Control Outputs
Range	±10 V @ 5 mA (2 kΩ or greater load) (For current output, use the VC2124 accessory:±10 mA to ±200 mA in 10 mA steps)
Tolerance	At 10 V: +200mV, -100 mV At 0 V: ±50mV At -10 V: +100 mV, -200 mV
Resolution	12 bits
Output Isolation	500 VAC
Overload Protection	One-second short-circuit duration
Overvoltage Protection	Outputs are protected by clamp diodes

LEDS

Axis 0 LED

Axis LED applies to the Drive 0 output or feedback input 0 as described below:

If Drive 0 is assigned to an axis that has an input (i.e. isn't output-only), then that axis will own the Axis 0 LED.
Otherwise, if a reference input axis (no output) uses input 0, then that axis will own the Axis 0 LED.
Otherwise, if Drive 0 is assigned to an output-only axis, then that axis will own Axis 0 LED.

Axis 1 LED

Axis 1 LED applies to the Drive 1 output or feedback input 1 as described below:

If Drive 1 is assigned to an axis that has an input (i.e. isn't output-only), then that axis will own the Axis 1 LED.
Otherwise, if a reference input axis (no output) uses input 1, then that axis will own the Axis 1 LED.
Otherwise, if Drive 1 is assigned to an output-only axis, then that axis will own the Axis 1 LED.

LED Colors

State	Description
Steady Off	No power or the output/input is not assigned to an axis.
Steady Green	The axis is either in closed loop control or is a reference axis. The axis is not halted.
Flashing Green	The output is in open loop and the axis is not halted (not possible for reference axes).
Flashing Red	A Closed Loop Halt or External Halt has occurred because an error bit is set (not possible for reference axes). The LED will not turn red due to a halt caused by a halt command.
Steady Red	An Open Loop Halt or Direct Output Halt has occurred because an error bit is set (for reference axes, any halt has occurred). The LED will not turn red due to a halt caused by a halt command.