AMR MC-4231 User manual

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MC-4231- CO MODBUS
ADDRESSABLE SENSOR
Manual Part Number 180-0547
November 28, 2001

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TABLE OF CONTENTS
TITLE PAGE
Table of Contents ...............................................................................................2
List Of Figures ...................................................................................................4
1. Introduction....................................................................................................5
1.0. General.............................................................................................5
1.1. Features............................................................................................5
1.2. Default Values .................................................................................6
1.3. New Features ...................................................................................6
2. Specifications..................................................................................................7
3. Setup................................................................................................................9
3.1. DS1 Setup Switch ............................................................................9
3.2. DS2 Cell Polarity.............................................................................10
3.3. DS3 2 Wire/4 Wire Comm .............................................................10
3.4. DS4 Comm Enable/Disable ............................................................11
3.5. DS5 2 Wire/3 Wire Cell ..................................................................11
3.6. DS6 Sensor Mode ............................................................................11
3.7. Address Switches.............................................................................11
3.8. Setup Adjust ....................................................................................11
3.9. Zero Adjust......................................................................................11
3.10. Reference Adjust...........................................................................12
3.11. Comm Fuses ..................................................................................12
4. Configuration .................................................................................................13
4.0. General.............................................................................................13
4.1. Current Loop Mode Sensor (Stand Alone)...................................13
4.2. Voltage Mode Sensor (Stand Alone) .............................................13
4.3. Monitor System Sensor/Remote ....................................................14
5. Installation......................................................................................................15
5.0. General.............................................................................................15
5.1. Power Connections .........................................................................16
5.1.1. Power Connection (Stand Alone Voltage Mode........................17
5.1.2. Power Connection (Voltage Mode in Permissible Area ...........18
5.2. Sensor Cell Connection ..................................................................19
5.3. Warn/Alarm Output Connection ..................................................19
5.4. Alarm Reset Switch Connection ....................................................19
5.5. Analog Input #1 and Analog Input #2 Connections ....................19

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TABLE OF CONTENTS(CONT.)
TITLE PAGE
5.6. Status Input #1 and Status Input #2 Connections .......................20
5.7. Control Output #1 and Control Output #2 Connections ............20
5.8. Calibration/Test Switch Connection .............................................20
5.9. 2-Wire Monitor System Connection ............................................20
5.10. 4-Wire Monitor System Connection ...........................................20
6. Calibration......................................................................................................23
6.0. General.............................................................................................23
6.1. Zero Calibration .............................................................................23
6.2. Span Calibration .............................................................................24
7.Testing..............................................................................................................25
7.0. General.............................................................................................25
7.1. Perform Test....................................................................................25
8. Installation Check List ..................................................................................26
9. Replacement Parts .........................................................................................27

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LIST OF FIGURES
TITLE PAGE
Figure 1, Connection and Configuration Diagram.........................................8
Figure 2, MC-4231-CO Monitor Connections ................................................16
Figure 3, Stand Alone Voltage Mode Connection to Monitor System..........17
Figure 4, Stand Alone Voltage Mode Sensor in Permissible Area ................18
Figure 5, MC-4231-CO Monitor Connection ..................................................21
Figure 6, 2 Wire Addressable Monitor Thru Barriers...................................21
Figure 7, MC-4231 (4 Wire Addressable Sensor) ...........................................22
Figure 8, 4 Wire Addressable Monitor Thru Barriers...................................22

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1. INTRODUCTION
1.0. General
The American Mine Research MC-4231-CO Modbus Addressable Sensor is a
compact monitor designed to be used with an Allen-Bradley PLC and Prosoft PLC to
Modbus Protocol Converter. Available in a varity of gases, it has the traditional
AMR quality construction, leading edge technology and maintenance free
characteristics. The MC-4231-CO Mosbus Sensor is essentially the same electronics
as the MC-4210-CO (see 0180-0545 manual) with the addition of audible and visual
alarms. It is typically used as a working section sensor and audible/visual warning
device to alert section personnel in case of high carbon monoxide levels.
1.1. Features
The features of the MC-4231-CO Modbus sensor are summarized below:
•Low current operation: Less than 3 ma.
•May be used in permissible areas with like type classification barriers
•Stand Alone Voltage Mode Operation
•High speed data rate: 19.2K baud standard
•4 Digit LCD Display
•Magnetically activated test and calibration switch (can be calibrated without
removing the cover)
•Microprocessor controlled calibration (no potentiometers to adjust)
•Smart operation: testing and calibration does not set off outside alarms.
•Alarm and Warning outputs adjustable
•Optional Zero Offset
•Valid communications with Master Station indication
•Sealed polycarbonate enclosure
•Highly visible 360 degree strobe light
•103 decible Sonalert (R)
•Uses City Technology sensor cells
•MSHA Classification XXXX

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1.2. Default Values
The unit is shipped from the factory with the following default settings:
•Output mode: Voltage
•Full-scale value: 50PPM
•Calibration gas : 50PPM
•Test value: 50PPM
•Warning level: 10PPM
•Alarm level: 15 PPM
•Zero Offset: 1 PPM (Zero Offset is optional and provided for some users)
1.3. New Features
The American Mine Research MC-4231-CO Modbus Sensor has all the features of
the earlier MC-4031 model and many more. Listed below are the new features of the
MC-4231-CO sensor.
•One PC board for both sensor and communications instead of two
•Three rotary BCD switches for address instead of DIP switch
•Addressable to 256 instead of 128
•Four digit LCD display allows better resolution and range.
•Sensor Cell ZERO calibration error and SPAN calibration error indication
•Can serve as a small inexpensive remote with the following input/outputs:
♦Two current sink type control outputs
♦Two 0 to 3 VDC status inputs
♦Two 0 to 3 VDC analog inputs.

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2. SPECIFICATIONS
•Size: 7”W x 7”H x 5”D
•Operating Voltage: +10VDC to +28VDC
•Operating Mode: Voltage Mode Only
•Operating Current: Voltage Mode = 3.0mA.
•Operating Current: Addressable Sensor = 5.5mA
•Voltage Mode Output: 0.1 volts for 0 ppm
•Voltage Mode Output: 3.0 volts for 50 ppm
•Full Scale Range: Dip Switch Selectable, 25 ppm or 50 ppm
•Calibration Gas: Dip Switch Selectable, 25 ppm or 50 ppm
•Display: Four Digit LCD
•Detection Principle: Diffusion Type Electro-chemical
•Trip Outputs: Open Collector Current sink 100mA
•Warn, Alarm Trip Level: User Adjustable
•Zero Offset Level User Adjustable (Provided for some users)
•Communication Interface: 2 Wire or 4 Wire RS-485
•Communicaton Baud Rate: 19200 baud standard
•Visual Indication LED Cluster
•Audible Indication 2 each Sonalerts

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FIGURE 1, CONNECTION AND CONFIGURATION DIAGRAM
(2 WIRE)
(POSITIVE)
2 WIRE COMM
COMM ENABLE
DS6 POSITION
19.2KBAUD RATE
NOT USED
VOLTAGE MODE

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3. SETUP
3.1. DS1 Setup Switch
The MC-4231-CO’s setup is determined by an internal 8 position dip switch
(DS1) as shown if Figure 1. The function of each position of the dip switch is
described below:
DS1 FUNCTIONS
SW# POSITION FUNCTION
1 OFF NO FUNCTION
1 ON LOAD DEFAULT VALUE
2 OFF 19.2K BAUD RATE
2 ON NOT USED
3 OFF SENSOR VOLTAGE MODE
3 ON SENSOR CURRENT MODE
4 OFF 25 PPM FULL SCALE SPAN
4 ON 50PPMFULLSCALESPAN
5 OFF 25 PPM CALIBRATION GAS
5 ON 50 PPM CALIBRATION GAS
6 OFF SELECT SETUP MODE
6 ON SETUP MODE OFF
7 AND 8 = SETUP MODE TRUTH TABLE BELOW
#7 #8 FUNCTION
ON ON SET WARN LEVEL
OFF ON SET ALARM LEVEL
ON OFF ZERO OFFSET VALUE (IF PROVIDED)
OFF OFF NOT USED NOW
Notes: 1) The zero offset value function is provided as an option to the user
by using special software. The user must request this software.
2) The MC-4231-CO may be used in the Voltage Mode Only
Switch DS1 is a multipurpose configuration and setup switch. Each switch of DS1is
described below:
(DS1-1) When placed to ON and power is then applied to the unit, the default
calibration gas and the warning and alarm trip levels are loaded into memory.
Note: After power has been applied, the DS1-1 switch must be placed to
OFF. The load default values function is for use only as a stand-
alone voltage or current mode sensor. When used as an address-
able sensor, the load default values should not be used. Use the
Master download function instead to change the span calibration
gas level.

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3.1. DS1 Setup Switch (Cont.)
(DS1-2) Selects the PLC Monitor System baud rate. OFF = 19.2K, ON=38.4K.
(DS1-3) Selects sensor output mode. OFF= voltage , ON= current.
Note: 1) The voltage mode should be used if the sensor is an addressable
type.
2) Voltage mode output of 0.1 volts represents 0 PPM and 3.0 volts
represents 50 PPM full scale.
3) Do not use Current Mode Operation because the Audible/
Visual Alarms will affect the loop current.
4) Place DS6 to agree with the mode switch
(DS1-4) Selects sensor full scale span range. OFF= 25 PPM, ON=50 PPM
(DS1-5) Selects sensor calibration gas value OFF = 25 PPM, ON= 50 PPM
(DS1-6) Enables the sensor setup mode to allow setting the warn, alarm and zero
offset levels using the setup potentiometer (R15).
OFF= SETUP MODE ENABLED, ON= SETUP MODE OFF.
(DS1-7,8) These two switches are used according to the truth table above to select
the warn or alarm value that is to be set using the SETUP potentiometer
(R15). To set one of these values, place DS1-6 switch to the OFF
position. The display will now read the current value given by the Setup
Adjust potentiometer(Figure1). The value idicated will be the previously
used position of the Setup Adjust potentiometer, not necessarily the value
of the currently selected parameter. Next, configure switches DS1-7,8
according to the above table. Using a small screwdriver, adjust potent-
iometer R15 until the desired value is displayed. Now briefly activate the
test/calibrate switch. The display will blink the setup value three times
indicating that the displayed value has been saved. You may now select
another parameter to set using the same procedure. Once all the values
have been set, return the DS1-6 switch position to ON.
3.2. DS2 Cell Polarity
DS2 is for FACTORY USE ONLY. It is used to match the sensor cell polarity for
each gas in the MC-4231 series. DS2 IS HARDWIRED FOR + POLARITY
(1-5, 2-3).
3.3. DS3 2 Wire/4 Wire Comm
DS3 allows the MC-4231 to operate with either a 2 wire monitor system interface
such as the MC-4000 system or a 4 wire monitor system. DS3 IS HARDWIRED
FOR 2 WIRE COMM (2-4, 5-6).