RoboteQ AX2850 user manual Wiring Optional Limit Switches

Installing, Connecting and Using the Encoder Mod-

Important Warning

When a limit switch is activated, the encoder signal that is shared with the switch is no longer visible by the encoder module, and pulse counting and speed measure- ment stops.

Wiring Optional Limit Switches

If limit switches are needed by the application, additional circuitry is required in order to create a multi-level signal that shares the encoder and the switch information. The figure below shows the electrical diagram of the required wiring.

		5V Out
	4.7kOhm	4.7kOhm
1kOhm		Ch A In

5V	Ch A
	Encoder
GND	Ch B

Ch B In

1kOhm

SW1 SW2

GND

Encoder Module

FIGURE 50. Signals seen by encoder using multi-levels and limit switches

Using this circuit when the switch is open, a 0V (low-level) output from the encoder goes through a 1k and 4.7k voltage divider, thus creating a voltage that will never be below 0.8V at the encoder module’s input.

When the switch is activated, the module’s input is pulled to 0V.

It is recommended that a voltmeter and/or oscilloscope be used to verify that the right volt- age levels are created as the encoder rotates and the switches activate.

You may also use the Encoder setup/test function in the Roborun utility (see “Encoder Testing and Setting Using the PC Utility” on page 83). If the wiring is correct, the counters should increment/decrement as the motor rotate. The switch indicators should be always off unless the switches are actually activated.

78 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007