S8 Module (RMC200)

8 SSI or Magnetostrictive Start/Stop or PWM inputs, supports one RS-422 quadrature input

The S8 module for the RMC200 provides eight inputs, individually software selectable as SSI (Synchronous Serial Interface), or magnetostrictive Start/Stop or PWM inputs. One RS-422 quadrature input (A+, A-, B+, B-) may be configured in software, using inputs 6 and 7 on the S8 module. Inputs 6 and 7 may be configured as a single SSI Monitor input.

Note: Linear magnetostrictive transducers with SSI output should be of the synchronized type. Non-synchronized is not well-suited for motion control. This does not apply to rotary SSI encoders.

Features

8 inputs, individually configurable for SSI, Start/Stop, or PWM
Binary or Gray Code
Rotary encoders or linear transducers
8 to 32 bits of data
Differential RS-422 SSI interface
Unpluggable terminal blocks
Supports one RS-422 quadrature input using channels 6 and 7, with A+, A-, B+, B- signals only. Does not support homing or registration.
Supports one SSI_Monitor input using channels 6 and 7.

Part Number

The part number of the S8 module is R200-S8.

Setting Up the S8 Module

Wiring

See S8 Wiring.

Configuring an RS-422 Quadrature Input or SSI Monitor

The S8 SSI/MDT inputs 6 and 7 can be configured as an RS-422 quadrature input or an SSI_Monitor input. See Configuring S8 Channels for details.

Axis Definitions

In order to use an S8 input (SSI, MDT, or quadrature), use the Axis Definitions dialog to assign it to an RMC internal software axis.

Feedback Parameters

After an S8 input has been assigned to an axis, the following axis parameters must be configured in Axis Tools in order for the S8 to communicate with the sensor:

SSI Transducers - Required	MDT Transducers - Required	Quadrature Encoders - Required
SSI/MDT Feedback Type SSI Data Bits SSI Format	SSI/MDT Feedback Type MDT Type	Linear/Rotary
Optional	Optional
Linear/Rotary SSI Clock Rate Wire Break Detection SSI Overflow Mode SSI Home Source SSI Termination SSI_High_Bits_to_Ignore SSI_Low_Bits_to_Ignore	MDT Blanking Period	AB Termination

Scale/Offset

After configuring the axis feedback parameters, the feedback value must be scaled to practical measurement units:

MDT Scaling

SSI Scaling

Quadrature Scaling

Specifications

General
Weight	386 g + 26 g (2 connectors)
SSI Interface
Data Inputs	RS-422 differential
Clock Outputs	RS-422 differential
Termination	Software selectable data input impedance: 110 Ω or >200 kΩ
Clock Frequency	User-selectable 100 kHz to 2500 kHz
Maximum Cable Length	Transducer Dependent, approx. 3-2100 ft. See the SSI Clock Rate topic for details.
Resolution	Transducer dependent
Count Encoding	Binary or Gray Code
Count Data Length	8 to 32 bits
Bit Masking	A selectable number of high or low bits may be masked
Additional Settings	Selectable overflow modes to conform to various SSI transducers Wire break detection
MDT Interface (Start/Stop or PWM)
Transducer interface types	MDT with Start/Stop or PWM (Pulse Width Modulated) feedback
Interrogation Outputs	RS-422 differential (transducer must be configured for external interrogation)
Return Inputs	RS-422 differential
Resolution	0.0005 in. with one recirculation
Count Rate	240 MHz
Recirculations	Supports multiple recirculations only for PWM transducers with internal recirculations.
Maximum transducer length	440 in. at 4ms (loop-time dependent)
Quadrature Interface
Input	5V differential (RS-422) receiver for A+, A-, B+, B-
Connection	Uses the following pins: A+: Input 6 Ret/Dat+ A- : Input 6 Ret/Dat- B+: Input 7 Ret/Dat+ B- : Input 7 Ret/Dat-
Input Impedance	Software selectable data input impedance: 110 Ω or >200 kΩ
Max Encoder Frequency	8,000,000 quadrature counts/second
Min Edge Alignment	55 ns time between A edge and B edge
Common
Functional Isolation	500 VAC
Power
Max Power Dissipation	1.8 W

LEDs

Light Bar

State	Description
Off	No power to the RMC200 or the module was not inserted when the RMC200 powered up.
Blue	The module was recognized at power-up.

Input LEDs: In0 .. In7

Each transducer input has an associated input LED:

LED State	Description
Off	The input is not assigned to an axis.
Green	Operating normally The input is assigned to an axis and is receiving a valid value from the transducer.
Red	Error The input is assigned to an axis and is not receiving a valid value from the transducer. This may be due to a transducer error, or due to incorrectly configured axis feedback parameters. Transducer errors that cause an invalid value on the S8 include: For SSI, there is a Wire Break condition and Wire Break Detection is enabled. For SSI, an SSI Overflow Pattern was detected. For Start/Stop or PWM, there was no start pulse detected or rising edge of the PWM response. For Start/Stop or PWM, there was no stop pulse or falling edge of the PWM response in the required time.
Amber	Simulate mode The axis is in simulate mode. Note: The input LED may appear to be amber for certain transducer errors when the RMC is alternately seeing a valid and invalid input, and the LED is switching between red and green colors quickly enough that the LED appears to be amber.