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Connecting power, Serial communications, Real time clock – Wavetronix Click 500 (programmable controller) (CLK-500) - User Guide User Manual

Page 44: Rs-232 ports

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CHAPTER 6 • CLICK 500

43

Real Time Clock

The real time clock on the Click 500 has a backup battery in order to maintain time in

the event of a power outage. However, like a wristwatch, this clock can drift forward and

backward by several seconds per day, so depending upon your application, you may need

to synchronize the clock.

Connecting Power

The Click 500 requires between 10 V and 30 V to be connected to the +DC and -DC pins on

the T-bus; the recommended voltage is 24 V. The easiest way to connect power to the T-bus

is to use a Click 201/202 AC to DC power supply (see Figure 6.3).

T-bus Connector

+DC

-DC

+485

-485
GND

RS-485

T-bus Port

Power

Supply

Figure 6.3 – Connecting Power through the T-bus

The GND, -DC, -I1 and -I2 ports (see Digital Inputs section) are all interconnected and

represent a common logic ground. The -DC terminal on the T-bus connector provides a

convenient termination point for DC power wiring. Likewise, the -I1 and -I2 terminals

provide a convenient termination point for the input common lines.

Serial Communications

The four independent serial ports are available through five serial port connectors.

RS-232 Ports

The two physically independent RS-232 serial ports are accessed via the DB-9 DCE con-

nector on the front of the module and a screw terminal connector on the top of the module.

Figure 6.4 shows the pin level descriptions for the RS-232 front connector.

The RS-232 front serial port is used to develop and debug applications when the device is

in program mode. This port can also be used in run mode to interact with other devices.

For example, in run mode this port is often used to interact with the computer-based Click

Supervisor device management software.