Troubleshooting & Repair Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 298

13.5.9.2. Troubleshooting Analyzer/Modem or Terminal Operation

These are the general steps for troubleshooting problems with a modem connected to a Teledyne analyzer.
1. Check cables for proper connection to the modem, terminal or computer.
2. Check to make sure the DTE-DCE is in the correct position as described in Section 8.1.1.
3. Check to make sure the set up command is correct. See Section 8.2.
4. Verify that the Ready to Send (RTS) signal is at logic high. The GFC 7001E/EM sets pin 7 (RTS) to
greater than 3 volts to enable modem transmission.
5. Make sure the BAUD rate, word length, and stop bit settings between modem and analyzer match. See
Section 8.2.
6. Use the RS-232 test function to send “w” characters to the modem, terminal or computer. See Section
8.2.
7. Get your terminal, modem or computer to transmit data to the analyzer (holding down the space bar is
one way); the green LED should flicker as the instrument is receiving data.
8. Make sure that the communications software or terminal emulation software is functioning properly.
Further help with serial communications is available in a separate manual “RS-232 Programming Notes”
Teledyne P/N 013500000.
13.5.10. THE OPTIONAL CO2 SENSOR
There are Two LED’s located on the CO2 sensor PCA.
Figure 13-13: Location of Diagnostic LED’s onCO2 Sensor PCA
Normal Operation: V8 is not lit – V9 is Blinking
Error State: Both LED’s are blinking.
Check to make sure that the cable to the CO2 probe is properly connected.