AP2 Expansion Module

The 2-axis Analog Pressure expansion module (AP2) is one of the optional expansion modules available for the RMC75 motion controller. This module provides two analog inputs with 16-bit resolution and support for position-pressure and position-force control.

The AP2 should not be confused with the A2, which provides analog input and no support for secondary pressure control. The RMC75 always requires an AP2 module for position-pressure or position-force control.

Note: Using the AP2 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
Broken wire detection

Part Number

The part number of the AP2 module is EXP70-AP2.

Uses

The AP2 is useful for the following purposes:

Dual-loop Control

The AP2 pressure or force inputs can be used in conjunction with the position or velocity control from an RMC7x axis module to provide the following combinations of dual-loop control:

- Position-Pressure or Position-Force
- Position-Acceleration (advanced)
- Velocity-Pressure or Velocity-Force
- Velocity-Acceleration (advanced)

Pressure/Force Control

The AP2 inputs, configured for pressure or force, can be used in conjunction with an output on an RMC75 axis module for solely pressure or force control. The RMC75 always requires an AP2 module for dual-loop. See the Position-Pressure and Position-Force Control and Position-Acceleration topics for more details.

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. If the application requires a position input and not a pressure or force input, the A2 Expansion module is a better choice.

Specifications

General
Weight	101 g + 16 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 (4-20mA)	20 ppm/ºC (0.003 %/ºC) typical*
Non-linearity	12 LSB (counts) typical (+10 V range)

*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.