A2 Expansion Module

The 2-input Analog expansion module (A2) is one of the optional expansion modules available for the RMC75 motion controller. This module provides two analog inputs with 16-bit resolution.

The A2 should not be confused with the AP2, which provides analog input with support for pressure control. If you do not require position-pressure/force or control, you do not need the AP2.

Note: Using the A2 module, it is possible to add more analog inputs on the RMC75 than can be assigned to axes. However, it is still possible to view the voltage of the extra analog inputs using the Analog Input Registers. Inputs that are unassigned to axes can have no status bits, error bits, scaling, filtering, etc.

Features

Two 16-bit voltage or current inputs - each individually selectable
±10 V and 4-20 mA input ranges
8 times oversampling
One +10 V exciter output
Broken wire detection

Uses

Analog Reference Input
Reference inputs are often used as gearing or camming masters. Reference inputs cannot be used for direct control of the input axis.
Input for a Control Axis
The A2 inputs can be used for the input of a control axis. The Control Output must be from an axis module.

Part Number

The part number of the A2 module is EXP70-A2.

Specifications

General
Weight	102 g + 19 g (connector)
Analog Interface
Inputs	Two 16-bit differential
Isolation	500 VAC
Overvoltage protection	±40 V
Input ranges	±10 V and 4 20 mA (each channel independently configured)
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: 5 MΩ Current Input: 250 Ω
Input filter slew rate	25 V/ms
Oversampling	8 times per control loop
Offset drift with temperature +10 V (4-20 mA)	0.2 LSB/ºC (1 µA/ºC) typical*
Gain drift with temperature +10V (4-20 mA)	20 ppm/ºC (0.003 %/ºC) typical*
Non-linearity	12 LSB (counts) typical (+10 V range)
Exciter Output	10 VDC ± 2%, 8 mA

*Max Offset Drift 4.8 µA/ºC, Max Gain Drift 0.009 %/ºC under maximum possible circuit component error amount.

LEDs

Input 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.