Fluke 5020A user manual Communications, Serial Wiring

Digital Communications Interface 6

Introduction

Introduction

The communication feature allows an external device, such as a computer, to communicate with the thermo-hygrometer readout to obtain measurement data and control operation settings. Communication is accomplished by issuing commands to the thermo-hygrometer readout through RS-232 or IR communication ports.

Communications

The thermo-hygrometer readout is equipped with an RS-232 serial interface and an infrared window. The serial interface allows communications up to distances of approximately 50 feet. The IR interface allows close proximity, line-of-sight, wireless communications. The serial interface and infrared window allow the user to access the functions, parameters, and settings discussed in Comm Setting.

Serial Wiring

The serial communications cable attaches to the thermo-hygrometer readout through the RS-232 port on the left side of the instrument. Figure 6-1 shows the pin-out of this connector and suggested cable wiring. Note the TxD line on one side connects to the RxD line on the other side and vice-versa. To eliminate noise, the serial cable should be shielded with low resistance between the connector and the shield.

The serial period, baud rate, linefeed, and echo (duplex) are programmable. Refer to Section , Comm Setting, for instructions on accessing and setting these parameters.

All commands sent to the thermo-hygrometer readout through the serial interface must be terminated with a carriage return (ASCII 0D hex, 13 decimal) or new line character (ASCII 0A hex, 10 decimal).

	GND	5
GND		9
		4
RxD	TxD	8
		3
	RxD	7
TxD		2
		6
		1

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Figure 6-1. Serial Cable Wiring

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