Filter
Top Products
Troubleshooting & Service T400 Ozone Analyzer Operator’s Manual
266
12.7.10. RS-232 COMMUNICATIONS
12.7.10.1. General RS-232 Troubleshooting
Teledyne API analyzers use the RS-232 communications protocol to allow the
instrument to be connected to a variety of computer-based equipment. RS-232 has been
used for many years and as equipment has become more advanced, connections between
various types of hardware have become increasingly difficult. Generally, every
manufacturer observes the signal and timing requirements of the protocol very carefully.
Problems with RS-232 connections usually center around the following general areas:
Incorrect cabling and connectors. See Section 3.3.1.8 for connector and pin-out
information.
The BAUD rate and protocol are incorrectly configured. See Section 6.2.2.
If a modem is being u
sed, additional configuration and wiring rules must be
observed. See Section 8.3
Incorre
ct setting of the DTE – DCE Switch is set correctly. See Section 6.1
Verify that ca
ble (03596) that connects the serial COM ports of the CPU to J12 of
the motherboard is properly seated
12.7.10.2. Troubleshooting Analyzer/Modem or Terminal Operation
To troubleshoot problems with a modem connected to a Teledyne API analyzer:
Check cables for proper connection to the modem, terminal or computer.
Check to make sure the DTE-DCE is in the correct position as described in Section
6.1.
Che
ck to make sure the set up command is correct (See Section 8.3)
Verify that th
e Ready to Send (RTS) signal is at logic high. The T400 sets pin 7
(RTS) to greater than 3 volts to enable modem transmission.
Make sure the BAUD rate, word length, and stop bit settings between modem and
analyzer match, See Section 6.2.2.
Use the
RS-232 test function to send “w” characters to the modem, terminal or
computer; See Section 6.2.2.
Get your te
rminal, 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.
Make sure that the communications software or terminal emulation software is
functioning properly.
Note Further help with serial communications is available in a separate manual
“RS-232 Programming Notes” Teledyne API part number 013500000.
06870C DCN6332