Signal Output; Serial Output; Analog (4-20 Ma) Outputs And Communications - Michell Instruments XTP501 User Manual

INSTALLATION
4.5.3

Signal Output

There are two 4-20mA linear signal output channels for target gas concentration. One is
fixed on the calibrated range of the unit and the second can be configured in the menu.
NOTE: When the instrument is warming up (cell temperature not stabilized)
these outputs are driven to 3.2 or 21.4 mA.
• The maximum mA output is approximately 20.5mA
• The minimum mA output is approximately 3.8mA
• The user can select the fault condition to drive the mA output Low (3.2mA)
or Hi (21.4mA).
4.5.4

Serial Output

The analyzer has Modbus RTU communications over RS485 protocol; please see
Application Software CD for more details.
• Type: Modbus RTU over RS485
• RS485: 2 wire (plus ground), half duplex
• Baud Rate: 9600
• Parity: None
• Data bits: 8
• Stop bits: 1
4.5.5

Analog (4-20 mA) Outputs and Communications

Warning: Do not attempt to loop-power this instrument via the 4-20 mA
output as this will irreversibly damage the main PCB.
36
Pin Number Description
1 Channel 2 -VE
2 RS485 B
3 Channel 1 -VE
4 Channel 1 +VE
5 RS485 A
6 Channel 2 +VE
7 RS485 GND
NOTE: The above view of the electrical
connections is shown from the mating side.
Here are the connections as viewed from the back of the
connector and this should be used for wiring purposes.
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99976 Issue 1.1, May 2020