MA Axis Module

The MA module is one of the axis modules available for the RMC75. It interfaces to Magnetostrictive Start/Stop and PWM and SSI transducers and has 1 analog servo output per axis. The MA module is available with either 1 or 2 axes, called the MA1 and the MA2.

For details on Magnetostrictive and SSI, see the Magnetostrictive Displacement Transducers and Synchronous Serial Interface topics.

Note:
Linear magnetostrictive transducers with SSI output must be of the synchronized type. See the SSI Fundamentals topic for details.

Important!
When using SSI, the MA module requires RS-422 (5 V differential) SSI inputs. It does not support single-ended SSI inputs or higher voltage inputs.

Features

One MDT or SSI input per axis - each axis individually selectable
One ±10 V, 16-bit control output per axis
Current output up to ±200mA with VC2124 converter option
Can be used for controlling position. Can also be used for dual-loop control such as position-pressure when used in conjunction with the AP2 module.
SSI can be used for rotary axes.

Part Number

The part numbers of the MA modules are MA1 and MA2 for the 1-axis and 2-axis versions, respectively.

For example, RMC75E-MA1 is an RMC75E with a MA1 module.

Supported Transducers

Many different versions of MDT and SSI transducers exist, and the RMC75 MA axis module supports a very wide variety of them. The following tables summarize the major transducer options supported by the MA module:

MDT Options	Value
Types	Start/Stop (S/S) Pulse-Width-Modulated (PWM)
Count Range	32 bits
Wiring	Differential, 5 V, RS-422
Interrogation Modes	External. Notice that internal interrogation is not supported.
MDT Count Rate	240 MHz
Output Resolution	16 bits

SSI Options	Value
Data Bits	8 to 32
SSI Format	Binary or Gray Code
SSI Errors	None, all zeros, all ones, or bit 21
Clock Rates	150, 250, and 375 kHz

Note:
Linear magnetostrictive SSI transducers must be of the synchronized type. This ensures that the time between position samples matches the control loop time of the RMC. If the transducer is not synchronized, the sample time may not match and make precise speed control difficult.

Blanking Period (For Neuter Outputs)

The RMC75 blanking period is set to 5µsec. Some older transducers, such as Temposonics I and II with neuter outputs, are not compatible with the RMC75 due to the short blanking period. They are compatible with the RMC150. For more details, see the MDT Fundamentals and MDT Blanking Period topics.

Setting Up the MA Module

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

MA Wiring

MDT Scaling

SSI Scaling

Specifications (per axis)

Each axis is individually selectable for MDT or SSI.

General
Weight	72 g (MA1), 71 g (MA2) + 22 g (per connector)
MDT Interface
Inputs	Two RS422 differential Note: single-ended is not supported
Outputs	Two RS422 differential Note: single-ended is not supported
ESD protection	15 kV
Resolution	0.0005" (12.7 μm) Start/Stop; 0.00005" (1.27 μm) PWM
Count Rate	240 MHz
SSI Interface
Inputs	Two RS422 differential
Clock Outputs	Two RS422 differential
Clock Frequency	Software selectable 150, 250, or 375 kHz.
Input Impedance	Data + Input: 148 Ω Data - Input: 185 Ω
Cable Type	Twisted pair, shielded
Cable Length Maximum	Transducer Dependent, approx. 300-600 ft. See the SSI Clock Rate topic for details.
ESD protection	15 kV
Resolution	Transducer dependent. Down to 1 μm (approx. 0.00004") for MDTs
Count Encoding	Binary or Gray Code
Count Data Length	8 to 32 bits
Control Output
Range	±10 V @ 5 mA (2 kΩ or greater load)(For current drive, use the VC2124 accessory:±10 mA to ±200 mA in 10 mA steps)
Tolerance At 10 V:	Currently unavailable
Resolution	16 bits
Output Isolation	Not isolated
Overload protection	One-second short-circuit duration
Overvoltage protection	Outputs are protected by clamp diodes
Fault Input
Input Characteristics	12-24 VDC, sinking or sourcing
Logic Polarity	True High
Input "High" Range	7 to 26.4 VDC (polarity independent) 3mA maximum
Input "Low" Range	0 to 3.5 VDC (polarity independent) <1 mA
Maximum Propagation Delay	100 µs
Enable Output
Output Type	Solid State Relay
Logic Polarity	User Selectable to Active Open or Active Closed
Isolation	500 VAC
Rated Voltage	12-24 V, max 30 V (DC or peak AC voltage)
Maximum Current	75 mA
Maximum Propagation Delay	2.0 ms
Closed	Low Impedance (50 Ω maximum)
Open	High Impedance (<1 µA leakage current at 250 V)

See the Fault Input and Enable Output topics for usage details.

LEDs

Axis LED
This LED represents the input and control status for the axis. This bi-color (red/green) LED has the following states:

State	Description
Steady Off	No power or this 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 input 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 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 halt command.

En/F LED
This LED represents the status of the Enable Output and Fault Inputfor the axis. This bi-color (red/green) LED will have the following states:

State	Description
Steady Off	No power or the Control Output is not assigned to an axis.
Steady Green	The Fault input is inactive, and the Enable output is active.
Flashing Green	The Fault input is inactive, and the Enable output is inactive.
Steady Red	The Fault input is active. Notice that it is not possible to tell if the Enable output is active or inactive.