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3M™ MicroTouch™ Controller RX142 Reference Guide

3M Touch Systems, Inc. Proprietary Information

CAUTION

To avoid possible damage to the controller, you must provide a path for electrostatic

discharge (ESD). The controller mounting hole near the sensor connector should be

used to connect to chassis safety ground and must be attached by the shortest possible

route to a good earth return (chassis) in all applications.

Note:

To avoid possible damage to one or both of the power supplies, do not supply

both internal power and external power to the controller. Power from two sources could

cause damage.

Using an Internal Power Supply to JP4

Provide power directly to the controller using JP4 (AMP 640457-3). Use a mating 3-pin

connector (AMP 3-640469-3 or equivalent) and connect Pin 1 to 5VDC power and Pin 2

to the return or (alternately) 12VDC to Pin 3 and Pin 2 to the return.

Using an Internal Power Supply with a Custom Serial Cable Design

When creating a custom serial cable connection, you can provide power to the controller

through the mating Molex connector. Refer to Table 1 for more information on actual

cable connections. Unlike using JP4 to supply power, you can only use 5VDC at the

serial interface.

1. Obtain an 8-pin Molex connector 51004-0800.

2. Attach power and ground to the connector, (Pin 6: +5V, Pin 7: Ground).

Mounting the Sensor

The RX142 controller will work with sensors that meet the following specifications. The

sensor may work beyond these limits but with reduced performance.

Minimum

Maximum

Capacitance top sheet to substrate

None

70nF

Resistance corner to corner or side to side

100 Ohm

500 Ohm

Resistance top sheet

100 Ohm

5k Ohm

It is critical for you to understand the tail orientation of your sensor prior to connecting

the controller. This will affect how the controller interprets your touch on the sensor.

Refer to the Chapter on controller communications for additional details.

Sensor Cable Connector

The sensor cable has a 4-pin single row locking female connector that plugs into the

controller. The controller is compatible with the “XYXY” latched connector pinout, not

the “”XXYY” style, non-latched connector pinout. Here, X or Y refers to one or the other

sheet, and + or – refers one or the other side of a sheet. The calibration process sorts out

left/right and up/down.

Connector pins 1 and 3 must be connected to one sheet and pins 2 and 4 must be

connected to the other sheet.