Teledyne 7300A manual 4 RS-232 Port, FET Series Resistance

2 Installation Model 7300A

The voltage from these outputs is nominally 0 V for the OFF and

15 V dc for the ON conditions. The maximum combined current that can be pulled from these output lines is 100 mA. (If two lines are ON at the same time, each must be limited to 50 mA, etc.) If more current and/or a different voltage is required, use a relay, power amplifier, or other matching circuitry to provide the actual driving current.

In addition, each individual line has a series FET with a nominal ON resistance of 5 ohms (9 ohms worst case). This could limit the obtainable voltage, depending on the load impedance applied. See Figure 2-8.

Figure 3-6: FET Series Resistance

2.3.4RS-232 Port

The digital signal output is a standard RS-232 serial communications port used to connect the analyzer to a computer, terminal, or other digital device. It requires a standard 9-pin D connector.

Output: The data output is status information, in digital form, updated every two seconds. Status is reported in the following order:

•The concentration in ppm or percent

•The range in use (00 = Range 1, 01 = Range 2, 10 = Range 3, 11 = Range 4)

•The span of the range (0-100 %, etc)

•Which alarms—if any—are disabled (AL–x DISABLED)

•Which alarms—if any—are tripped (AL–x ON).

Each status output is followed by a carriage return and line feed.

Input: The input functions using RS-232 that have been implemented to date are described in Table 2-8.

2-10 Teledyne Analytical Instruments