3-10 | Thermox CG1000 Oxygen Analyzer
Oxygen/flow alarm connections are configurable in software to activate
under a variety of user defined conditions, and are associated with the
following on J8:
ALARM 3A
Pin 12
ALARM 3B
Pin 13
ALARM 4A
Pin 14
ALARM 4B
Pin 15
See Chapter 4 for complete information on all alarms, including what they
can track and how they operate.
RS-485 Communications Connections
The CG1000 can communicate with other computers that use the same
protocol and have the same hardware interface. See Appendix A in the
back of this manual for information on the RS-485 serial communications
protocol.
The connections used for RS-485 2-wire communications on connector J7
are labeled as follows (see Figure 3-5 for location of J7 on the back of the
CG1000):
GND
Pins 1, 6-9
4WT+/2WRT+
Pin 2
4WT-/2WRT-
Pin 3
4WR+
Pin 4
4WR-
Pin 5
Connect all the 2-wire pluses (+) and all the 2-wire minuses (-) in paral-
lel with all the devices (in daisy-chain fashion), including all the CG1000
analyzers on the network and the host computer. In addition, on the host
computer, connect the receive and transmit terminal block connections.
Be sure to use twisted-pair cable in either rigid metal conduit or an overall
braided shield for all connections.
Remove the instrument cover to check the settings for the SW1:
2-Wire Switch Settings:
SWITCH # ON/OFF
SW1 – 1:
N/A for 2-Wire
Termination Resistor
SW1 – 2:
OFF
Sets type of RS485 communication
SW1 – 3:
ON
Termination Resistor
SW1 – 4:
Not used
4-Wire Switch Settings:
