Marathon OXYMITH TRANSMITTER F200060 - Manual (Page 5)

Page 2 of 23
11/14/2006 Rev. 14
General Description
The Oxymit™ Transmitter has been designed to work as an analog or digital interface for
any zirconia based oxygen probe used to track dew point, carbon potential, or oxygen. The
transmitter connects to the temperature and millivolts outputs of an oxygen probe and can
produce analog outputs proportional to the selected process value.
The features available are:
 Isolated inputs for thermocouple and probe millivolt
 24 bit Sigma-Delta ADC for inputs.
 Serial EEPROM to store setup and calibration values.
 Two isolated self-powered 4-20mA outputs for process value and temperature.
The transmitter makes a carbon or oxygen probe an intelligent stand alone sensor. The
transmitter is located near the probe, preferably mounted in an enclosure. The transmitter
mounts onto a DIN rail and requires a 24VDC power supply. It measures the probe
temperature and millivolts. At the time of order the transmitter can be configured to
calculate percent carbon, dewpoint, or percent oxygen from these inputs. The results of
any of these calculations are made available via two 4-20mA loop outputs. Typically one
first loop is set up for the process value the second loop transmits probe temperature.
Process
Controller
5
6
8
A/D
CONV.
RS485
14
13
D/A
D
-15V
D D
+15V
1
2
D/A
C
-15V
C C
+15V
5V_A
5V_A
EEPROM
12
11
Power
Supplies
5V_A
5V_B
+15V
-15V
+15V
-15V
B
A
5V_B
5V_A
22M
5V_A
44M
DISPLAY
CONN.
ISOLATED
ISOLATED
ISOLATED
T/C INPUT
mV INPUT
+24V
24V
COM
ANALOG
OUT 1
4-20mA
ANALOG
OUT 2
4-20mA
9
10 RTX+
RTX-
4
3
EVENT INPUT
7
Figure 1 BLOCK DIAGRAM