A8 Module (RMC200)

8 Analog Inputs

The A8 module is an 8-input analog voltage or current module for the RMC200. Each input supports ±10V, 4-20 mA, or ±20 mA.

Features

8 differential inputs
Inputs individually configurable for ±10V, 4-20 mA, or ±20 mA
18 bits resolution ADCs with oversampling for increased effective resolution and noise reduction
200 kHz internal sampling rate
Broken wire detection
Can be used for position, velocity, pressure, and force inputs.
Unpluggable terminal blocks
+10 VDC exciter for potentiometers (not for powering transducers)

Part Number

The part number of the A8 module is R200-A8.

Setting Up the A8 Module

Wiring

See A8 Wiring.

Axis Definitions

In order to use an A8 input, it must be assigned to an RMC internal software axis, via the Axis Definitions Dialog.

Feedback Parameters

After an A8 input has been assigned to an axis, the following axis parameters must be configured:

The Analog Input Filter also applies to the A8, but typically need not be changed.

Scale/Offset

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

Analog Position Scaling

Analog Velocity Scaling

Analog Acceleration Scaling

Analog Pressure/Force Scaling

Recovering From Saturation

When an analog input on the A8 module is driven beyond the -10.5 to 10.5 V range, the input is said to be saturated. This also occurs when the input is unconnected, since internal biasing circuitry will drive the input fully negative so that the RMC can detect that the input is disconnected. After being saturated, the input may take up to 5 seconds to fully recover once a voltage in the valid range is applied. During this time, a small offset approximately on the order of 300 microvolts may persist.

Specifications

General
Weight	399 g + 26 g (2 connectors)
Analog Input Interface
Inputs	Eight 18-bit differential inputs (higher resolution obtained by oversampling)
Functional Isolation	500 VAC
Overvoltage protection	±24 V
Nominal Input Ranges	±10 V, 4-20 mA, ±20 mA (each input independently configurable)
Max Differential Ranges	Voltage: -10.5 V to +10.5 V Current: -20 mA to +20 mA (continuous), -25 mA to +25 mA (peak)
Max Input Voltage Range	In+ or In- relative to Cmn: -14 V to +14 V typical
Broken wire detection	When the input is not connected, internal biasing pulls the input voltage down to its full negative value.
Input impedance	Voltage input: 1 MΩ Current input: 250 Ω
Input filter slew rate	25 V/ms
Sampling frequency	200 kHz internal sampling. Provides one filtered sample per control loop (e.g. 1 msec) to CPU.
Sampling filter	250 Hz – 4 kHz, user-selectable internal low-pass sampling filter.
Offset drift with temperature	0.2 LSB/°C typical (±10 V range)
Gain drift with temperature	20 ppm/°C typical (±10 V range)
Non-linearity	12 LSB (counts) typical (±10 V range)
Exciter output	10 Vdc ± 2%, 40 mA max total of all exciter outputs per terminal block
Power
Max Power Dissipation	1.4-2.4 W, depending on use of Exciter Output

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:

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 include: The differential analog input signal is outside the user-specified Overflow/Underflow Limit parameters. One or both of the individual input signals (In+ and In-) are outside the acceptable range.
Amber	Simulate mode The axis is in simulate mode.