MSA Ultima MOS-5, General Monitors S4000TH Instruction Manual

Hydrogen Sulfide Gas Detection

Ultima® MOS-5

Intelligent Sensor for

The information and technical data disclosed in
this document may be used and disseminated
only for the purposes and to the extent
specifically authorized in writing by MSA.

Instruction Manual 04-14

MSA reserves the right to change published
specifications and designs without prior notice.

Part No. MANMOS5
Revision 1

MANMOS5

Ultima MOS-5 Detector

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Ultima MOS-5 Detector

Table of Contents

TABLE OF FIGURES .................................................................................................................. VI

TABLE OF TABLES ................................................................................................................... VII

QUICK START GUIDE ................................................................................................................. 1

Mounting and Wiring ............................................................................................................................... 1

Tools Required ……..…………………………………………………………………………………………...1

Terminal Connections ............................................................................................................................. 1

1.0 INTRODUCTION .................................................................................................................... 4

1.1 Protection for Life ....................................................................................................................... 4

1.2 Special Warnings ....................................................................................................................... 4

1.3 System Integrity Verification ...................................................................................................... 5

2.0 PRODUCT DESCRIPTION ..................................................................................................... 7

2.1 General Description ................................................................................................................... 7

3.0 INSTALLATION ...................................................................................................................... 8

3.1 Receipt of Equipment ................................................................................................................. 8

3.2 Tools Required ........................................................................................................................... 8

3.3 Choosing Product Locations ...................................................................................................... 8

3.3.1 Remote Mounting of the Sensor from the Electronics .................................................. 9

3.4 Mounting and Wiring ................................................................................................................ 10

3.5 Terminal Connections .............................................................................................................. 11

3.5.1 Terminal Block TB1 – Sensor Connections ................................................................ 11

3.5.2 Terminal Block TB2 – Power and Signal Connections ............................................... 12

3.5.3 DC Power and Ground Connections ........................................................................... 13

3.5.4 Analog Signal Connections ......................................................................................... 13

3.5.5 Terminal Block TB3 – Relay Connections .................................................................. 14

3.5.6 European Union (EU) Approved Applications ............................................................. 15

3.5.7 Cable Termination in the Non-hazardous Area .......................................................... 15

3.6 Maintaining the X/P Integrity .................................................................................................... 15

4.0 OPERATION ......................................................................................................................... 17

4.1 Start-Up Checklist .................................................................................................................... 17

4.2 Start-Up .................................................................................................................................... 17

4.3 Relay Reset .............................................................................................................................. 17

4.4 User Selectable Options .......................................................................................................... 18

4.4.1 Ultima MOS-5 Intelligent Sensor User Menu Structure .............................................. 19

4.4.2 Sensor Range ............................................................................................................. 19

4.4.3 Calibration Output ....................................................................................................... 20

4.4.4 Warning Relay Settings .............................................................................................. 20

4.4.5 Alarm Relay Settings................................................................................................... 21

4.4.6 Modbus Channel 1 Settings ........................................................................................ 21

4.4.7 Modbus Channel 2 Settings ........................................................................................ 22

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Ultima MOS-5 Detector

4.5

HART........................................................................................................................................ 22

4.6 Gas Check Mode ..................................................................................................................... 23

4.6.1 Procedure for Checking the Calibration ...................................................................... 23

4.7 Calibration ................................................................................................................................ 24

4.7.1 Calibration Procedure ................................................................................................. 24

4.7.2 Aborting Calibration..................................................................................................... 25

4.7.3 Remaining Sensor Life ................................................................................................ 25

4.7.4 Initializing the Remaining Sensor Life ......................................................................... 26

4.8 Calibration Equipment .............................................................................................................. 26

4.8.1 Calibrating with a Breaker Bottle and Ampoules ........................................................ 26

4.8.2 Calibrating with an H2S Portable Purge Calibrator ..................................................... 26

5.0 MAINTENANCE ................................................................................................................... 28

5.1 General Maintenance ............................................................................................................... 28

5.2 Storage ..................................................................................................................................... 28

6.0 TROUBLESHOOTING ......................................................................................................... 29

6.1 Fault Codes and Their Remedies ............................................................................................ 29

6.1.1 F2 - Failed to Complete the Calibration ...................................................................... 29

6.1.2 F3 Flash Checksum Error ........................................................................................... 29

6.1.3 F4 - Sensor Heater Open Error or Sensor Amplifier Error .......................................... 29

6.1.4 F5 - Sensor Heater Shorted Error ............................................................................... 30

6.1.5 F6 - Low Supply Voltage ............................................................................................. 30

6.1.6 F7 - EEPROM Verification Failure .............................................................................. 30

6.1.7 F8 - Failure to Complete Setup ................................................................................... 30

6.1.8 F9 - Gas Check Period Exceeded .............................................................................. 31

6.1.9 F10 – Switch Error ...................................................................................................... 31

6.1.10 F11 Internal Error ........................................................................................................ 31

7.0 CUSTOMER SUPPORT ....................................................................................................... 32

7.1 MSA Office ............................................................................................................................... 32

8.0 MODBUS INTERFACE ........................................................................................................ 33

8.1 Baud Rate ................................................................................................................................ 33

8.2 Data Format ............................................................................................................................. 33

8.3 Modbus Read Status Protocol (Query/Response) ................................................................... 33

8.3.1 Modbus Read Query Message ................................................................................... 33

8.3.2 Modbus Read Response Message ................................................................................. 35

8.4 Modbus Write Command Protocol (Query/Response) ............................................................ 35

8.4.1 Modbus Write Query Message ................................................................................... 35

8.4.2 Modbus Write Response Message ............................................................................. 35

8.5 Function Codes Supported ...................................................................................................... 36

8.6 Exception Responses and Exception Codes ........................................................................... 36

8.6.1 Exception Response ................................................................................................... 36

8.6.2 Exception Code ........................................................................................................... 37

8.7 Ultima MOS-5 Intelligent Sensor Command Register Locations ............................................. 38

8.8 Ultima MOS-5 Intelligent Sensor Command Register Details ................................................. 41

8.8.1 Analog (00H) ............................................................................................................... 41

8.8.2 Mode (01H) ................................................................................................................. 41

8.8.3 Status/Error (02H) ....................................................................................................... 41

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Ultima MOS-5 Detector

8.8.4

Not Used (03H) ........................................................................................................... 42

8.8.5 Unit Type (04H) ........................................................................................................... 42

8.8.6 Software Revision (05H) ............................................................................................. 42

8.8.7 Status Block (06H) ...................................................................................................... 42

8.8.8 Analog Value (06H) ..................................................................................................... 42

8.8.9 Mode & Error (07H) ..................................................................................................... 42

8.8.10 Error Sensor & Sensor Life (08H) ............................................................................... 42

8.8.11 Display (0x09H & 0x0AH) ........................................................................................... 43

8.8.12 Serial Number (0BH/0CH) .......................................................................................... 43

8.8.13 Alarm Settings (0DH) .................................................................................................. 43

8.8.14 Warn Settings (0EH) ................................................................................................... 44

8.8.15 Com1 Address (0FH) .................................................................................................. 44

8.8.16 Com1 Baud Rate (10H) .............................................................................................. 44

8.8.17 Com1 Data Format (11H) ........................................................................................... 45

8.8.18 Com2 Address (12H) .................................................................................................. 45

8.8.19 Com2 Baud Rate (13H) .............................................................................................. 45

8.8.20 Com2 Data Format (14H) ........................................................................................... 45

8.8.21 Not Used (15H) ........................................................................................................... 46

8.8.22 Reset Alarms (16H) ..................................................................................................... 46

8.8.23 Sensor Life (17H) ........................................................................................................ 46

8.8.24 Sensor Scale (18H) ..................................................................................................... 46

8.8.25 MODEL 10K Controller (Co – Calibration Output) (19H) .......................................... 46

8.8.26 Not Used (1A, AB, 1C H) ............................................................................................ 46

8.9 HART Enable (1D H) ................................................................................................................ 46

8.9.1 HART Test (1Eh) ......................................................................................................... 46

8.9.2 Abort Calibration (1Fh) ................................................................................................ 47

8.9.3 Total Receive Errors (20H) ......................................................................................... 47

8.9.4 Bus Activity Rate % (21H) ........................................................................................... 47

8.9.5 Function Code Errors (22H) ........................................................................................ 47

8.9.6 Starting Address Errors (24H) ..................................................................................... 47

8.9.7 RXD CRC Errors Hi (25H) .......................................................................................... 47

8.9.8 RXD CRC Errors Lo (Same as Hi) (26H) .................................................................... 47

8.9.9 Parity Errors (27H) ...................................................................................................... 47

8.9.10 Overrun Errors (28H) .................................................................................................. 48

8.9.11 Framing Errors (29H) .................................................................................................. 48

8.9.12 Total Software CH1 Errors (2AH) ............................................................................... 48

8.9.13 Not Used (2BH) ........................................................................................................... 48

8.9.14 Clear Hardware Errors (2CH) ..................................................................................... 48

8.9.15 Clear Communication Errors (2DH) ............................................................................ 48

8.9.16 User Information (60H to 6FH) .................................................................................... 51

8.9.17 CH2 Total Receive Errors (70H) ................................................................................. 52

8.9.18 CH2 Bus Activity Rate % (71H) .................................................................................. 52

8.9.19 CH2 Function Code Errors (72H) ................................................................................ 52

8.9.20 CH2 Starting Address Errors (73H) ............................................................................ 52

8.9.21 CH2 Number of Register Errors (74H) ........................................................................ 52

8.9.22 CH2 RXD CRC Errors Hi (75H) .................................................................................. 52

8.9.23 CH2 RXD CRC Errors Lo (Same as Hi) (76H) ........................................................... 52

8.9.24 CH2 Parity Errors (77H) ............................................................................................. 52

8.9.25 CH2 Overrun Errors (78H) .......................................................................................... 52

8.9.26 CH2 Framing Errors (79H) .......................................................................................... 53

8.9.27 CH2 Total Software CH1 Errors (7AH) ....................................................................... 53

8.9.28 Not Used (7BH) ........................................................................................................... 53

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Ultima MOS-5 Detector

8.9.29

CH2 Clear UART Errors (7CH) ................................................................................... 53

8.9.30 CH2 Clear Stats (7DH) ............................................................................................... 53

9.0 APPENDIX ............................................................................................................................ 54

9.1 Warranty ................................................................................................................................... 54

9.2 Principle of Operation ............................................................................................................... 54

9.3 Specifications ........................................................................................................................... 55

9.3.1 System Specifications ................................................................................................. 55

9.3.2 Mechanical Specifications ........................................................................................... 55

9.3.3 Electrical Specifications .............................................................................................. 55

9.3.4 Environmental Specifications ...................................................................................... 57

9.4 Approvals ................................................................................................................................. 57

9.5 Spare Parts and Accessories ................................................................................................... 57

9.5.1 Sensors ....................................................................................................................... 57

9.5.2 Sensor Housing ........................................................................................................... 58

9.5.3 Sensor Accessories .................................................................................................... 58

9.5.4 Calibration Equipment ................................................................................................. 58

9.5.5 Intelligent Sensor (Ultima MOS-5 Intelligent Sensor) Replacement Parts ................. 59

9.5.6 Recommended Spare Parts for One Year .................................................................. 59

9.6 FM Approval ............................................................................................................................. 60

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Ultima MOS-5 Detector

Table of Figures

Figure 1: Ultima MOS-5 Intelligent Sensor Outline and Mounting Dimensions, in inches ..................................... 1

Figure 2: Spring Type Terminal Block Operation ................................................................................................... 2

Figure 3: Screw Type Terminal Block Operation .................................................................................................... 2

Figure 4: Ultima MOS-5 Intelligent Sensor ............................................................................................................. 7

Figure 5: Ultima MOS-5 Intelligent Sensor Outline and Mounting Dimensions, in inches ................................... 10

Figure 6: Ultima MOS-5 Intelligent Sensor Terminal Block Locations ................................................................. 11

Figure 7: Spring Type Terminal Block Operation ................................................................................................. 12

Figure 8: Screw Type Terminal Block Operation .................................................................................................. 13

Figure 9: Wire Strip Length ................................................................................................................................... 13

Figure 10: Relay Protection for DC and AC Loads ............................................................................................... 14

Figure 11: Relay Reset ......................................................................................................................................... 18

Figure 12: User Menu Structure ........................................................................................................................... 19

Figure 13: Gas Check ........................................................................................................................................... 23

Figure 14: Automatic Calibration Mode ................................................................................................................ 24

Figure 15: Calibration in Progress Mode .............................................................................................................. 24

Figure 16: Calibration Complete Mode ................................................................................................................. 25

Figure 17: Ampoules............................................................................................................................................. 26

Figure 18: Portable Purge Calibrator .................................................................................................................... 27

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Ultima MOS-5 Detector

Table of Tables

Table 1: TB2 Power and Signal Connections ....................................................................................................... 12

Table 2: Alarm Relay Connections ....................................................................................................................... 14

Table 3: Warn Relay Connections ........................................................................................................................ 14

Table 4: Fault Relay Connections ........................................................................................................................ 14

Table 5: MSA Contact Information ....................................................................................................................... 32

Table 6: Data Format ............................................................................................................................................ 33

Table 7: Exception Codes .................................................................................................................................... 37

Table 8: Command Register Locations ................................................................................................................ 40

Table 9: Com1 Baud Rate .................................................................................................................................... 45

Table 10: Com1 Data Format ............................................................................................................................... 45

Table 11: Com2 Baud Rate .................................................................................................................................. 45

Table 12: Com2 Data Format ............................................................................................................................... 46

Table 13: Sensor Scale ........................................................................................................ ................................ 46

Table 14: 24 VDC Cable Lengths ......................................................................................................................... 56

Table 15: Analog Output Cable Lengths .............................................................................................................. 56

Table 16: Sensor Cable Lengths .......................................................................................................................... 56

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Ultima MOS-5 Detector

Quick Start Guide

Mounting and Wiring

Tools Required

• “5mm” Allen head wrench to remove enclosure lid (included with gas detector).

• Flat-head screwdriver maximum 3/16 in (5 mm) width for terminal block (not inclu ded).

• Adjustable wrench for conduit or cable gland connections (not inclu ded).

The outline and mounting dimensions for the Ultima MOS-5 Intelligent Sensor (Figure 1) should
be used when making installation determinations.

Information on Class I Division 1 and Zone 1 wiring methods can be found in the NEC and
CEC.

WARNING: Acetic acid will cause damage to metal components, metal hardware, ceramic

IC’s, etc. If damage results from the use of a sealant that outgases acetic acid
(RTV silicone), the warranty will be void.

Figure 1: Ultima MOS-5 Intelligent Sensor Outline and Mounting Dimensions, in inches

Terminal Connections

The terminal blocks (TB) are located inside the housing and can be accessed by removing the
cover. A label inside of the housing cover provides a diagram of all the terminal connections.

It is recommended that a minimum three-wire shielded cable be used for making the power and
0-20mA Output connection on TB2 of the Ultima MOS-5 Intelligent Sensor. It is also
recommended that separate two-wire shielded twisted pair cables be used for making the
Modbus connections. The spring type terminal block accepts 14 AWG to 20 AWG and the

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Ultima MOS-5 Detector

screw type terminal block accepts 12 AWG to 18 AWG stranded or solid wire. Each wire should
be stripped before wiring the Ultima MOS-5 Intelligent Sensor. To connect wiring to the spring
type terminal block, insert a screwdriver into the orange tab and press down (Figure 2), opening
the terminal. Insert the wire into the terminal and release the orange tab, clamping the wire in
the terminal. Check the hold of the wire by gently tugging it to ensure it is locked in.

Figure 2: Spring Type Terminal Block Operation

To connect wiring to the screw type terminal block, loosen the top screw counter clock wise
(Figure 3). Insert the wire into the terminal and tighten the top screw clockwise.

Figure 3: Screw Type Terminal Block Operation

NOTE: Power must remain disconnecte d until all other wiring connections have been made.

The maximum distance between the Ultima MOS-5 Intelligent Sensor and the power supply is
2,000 feet or 610 meters (each cable run should be as short as possible). See Section 9.3.3 for
cable length specifications.

Connect +24 VDC to TB2, position 9. Connect the ground or common wire to TB2, position 8.
For making power and ground connections to display devices, see Figures 2 and 3.

To connect the analog signal, please refer to Section 3.5.4.

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Ultima MOS-5 Detector

MSA recommends that the Ultima MOS-5 Intelligent Sensor be calibrated 1 hour after start-up
and that the calibration be checked at least every 90 days to ensure system integrity.

The instrument is now ready to operate. Please consult the manual for more information on the
instrument’s many features.

NOTE: If in case of device failure during set-up or testing, please consult Troubleshooting

(Sec. 6.0) or call the factory.

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Ultima MOS-5 Detector

1.0 Introduction

1.1 Protection for Life

MSA’s mission is to benefit society by providing solutions through industry leading safety
products, services, and systems that save lives and protect capital resources from the dangers
of hazardous flames, gases, and vapors.

This manual provides instruction for installing and operating the Ultima MOS-5 Intelligent
Sensor for hydrogen sulfide gas detection. Although the Ultima MOS-5 Intelligent Sensor is
easy to install and operate, this manual should be read in full and the information contained
herein understood before attempting to place the system in service.

The safety products you have purchased should be handled carefully and installed, calibrated,
and maintained in accordance with the respective product instruction manual. Remember these
products are for your safety.

1.2 Special Warnings

The Ultima MOS-5 Intelligent Sensor contains components, which can be damaged by static
electricity. Special care must be taken when wiring the system to ensure that only the
connection points are touched.

WARNING: Hydrogen sulfide (H

loss of consciousness or death.

S) is an extremely toxic gas, and exposure may result in a

2

DO NOT OPEN WHEN AN EXPLOSIVE ATMOSHPERE IS PRESENT.
READ AND UNDERSTAND INSTRUCTION MANUAL BEFORE
OPERATING OR SERVICING. OPEN CIRCUIT BEFORE REMOVING
COVER.

NE PAS OUVRIR UN PRÉSENCE D’ATMOSPHÉRE EXPLOSIVE. LIRE
ET COMPRENDRE MANUEL D’INSTRUCTIONS AVANT D’UTILISER OU
SERVICE. OUVRIR LE CIRCUIT AVANT D'ENLEVER LE COUVERCLE.

SPECIAL CONDITIONS OF SAFE USE PERTAINING TO ATEX/IECEx INSTALLATIONS:

The Ultima MOS-5 shall not be used as a Safety Related Device as defined by ATEX Directive
94/9/EC,

When alternative detector elements are utilized, they shall only be mounted remotely in a
suitable certified enclosure in accordance with requirements of their respective certificates and
relevant local requirements. The associated cable shall be connected to the Intelligent Gas
Sensors using a suitably certified cable entry device with a ¾” thread form.

The Universal Gas Sensor (P/N 51457-XX) is suitable for use with the following enclosure
types and service temperature ranges that are dependent on the type of cement used in their
construction; therefore, they shall only be used with the enclosure type and where the surface
temperature, at the point of mounting, is as detailed below:

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Ultima MOS-5 Detector

Cement Ambient Range Enclosure Type

2850FT Cat 11
or 2762 Cat 17

2850FT Cat 11 -40°C to +120°C Enclosures that are certified by a notified body and

2762 Cat 17 -40°C to +180°C Enclosures that are certified by a notified body and

-40°C to +70°C Enclosures that are certified by a notified body and
satisfy the requirements of the current edition of EN
60079-1 or EN 60079-7 and European Directive
94/9/EC.

satisfy the requirements of the current edition of EN
60079-7 and European Directive 94/9/EC.

satisfy the requirements of the current edition of EN
60079-7 and European Directive 94/9/EC.

1.3 System Integrity Verification

To ensure operation at optimum performance, MSA recommends that certain maintenance
items be performed.

Commissioning Safety Systems

Before power-up, verify wiring, terminal connections and stability of mounting for all integral
safety equipment including the following items:

• Power supplies

• Control modules

• Field detection devices

• Signaling and output devices

• Accessories connected to field and signaling devices

After the initial application of power (and any factory specified warm-up period) to the safety
system, verify that all signal outputs, to and from devices and modules, are within the
manufacturers’ specifications. Initial calibration, calibration checking, or testing should be
performed per the manufacturer’s recommendations and instructio ns.

Proper system operation should be verified by performing a full, functional test of all component
devices of the safety system, ensuring that the proper levels of alarming occur.

Fault and malfunction circuit operation should be verified.

Periodic Testing/Calibration of Field Devices

Periodic testing/calibrating should be performed per the manufacturer’s recommendations and
instructions. Testing/Calibrating procedures should include, verify integrity of all optical surfaces
and devices

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Ultima MOS-5 Detector

When testing produces results outside of the manufacturer’s specifications, re-calibration or
repair and replacement of the suspect device(s) should be performed as necessary. Calibration
intervals should be independently established through a documented procedure, including a
calibration log, maintained by plant personnel or third party testing services.

Periodic System Verification

The following system verifications should be performed at least annually:
Verify wiring, terminal connections and stability of mounting for all integral safety equipment

including, the following items:

• Power supplies

• Control modules

• Field detection devices

• Signaling and output devices

• Accessories connected to field and signaling devices

Calibration intervals should be independently established through a documented procedure,
including a calibration log maintained by plant personnel or third party testing services.

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Ultima MOS-5 Detector

2.0 Product Description

2.1 General Description

The Ultima MOS-5 Intelligent Sensor is for the detection of hydrogen sulfide (H2S) gas. The
microprocessor-based electronics process information at the sensor site within an explosion­proof housing.

A digital display provides indications and display codes that can be viewed through a window in
the cover. A red LED above the digital display signifies an “alarm” condition, while a red LED
below the digital display signifies a “warning” condition. Analog signal (4-20 mA) and relays
provide remote and/or discrete indications of the sensor’s operation. Optional dual redundant
Modbus, HART, or HART and single Modbus provide digital communication.

The Ultima MOS-5 Intelligent Sensor is rated explosion-proof for use in the following hazardous
areas:

• CSA/FM: Class I, Division 1, Groups B, C, D and Class I, Zone 1, IIB+H

• ATEX/IECEx: Zone 1, Group IIB + H

2

2

7

Figure 4: Ultima MOS-5 Intelligent Sensor

Ultima MOS-5 Detector

3.0 Installation

3.1 Receipt of Equipment

All equipment shipped by MSA is pre-packed in shock absorbing containers, which provide
protection against physical damage (original containers should be kept for future shipping or
storage needs).

Shipping container contents should be carefully removed and checked against the packing list.
If any damage has occurred or there is any discrepancy in the order, please notify MSA as
soon as possible.

All correspondence with MSA must specify the equipment part number and serial number.
Although the factory tests each unit, a complete system checkout is suggested upon initial

installation to ensure system integrity.
WARNING: Only suitably skilled and competent personnel should carry out installation and

maintenance.
WARNING: The Ultima MOS-5 Intelligent Sensor contains components, which can be

damaged by static electricity. Special care must be taken when wiring the system to ensure that
only the connection points are touched.

3.2 Tools Required

• “5mm” Allen head wrench to remove enclosure lid (included with gas detector).

• Flat-head screwdriver maximum 3/16 in (5 mm) width for terminal block connections

(not included).

• Adjustable wrench for conduit or cable gland connections (not inclu ded).

3.3 Choosing Product Locations

There are no standard rules for sensor placement, since the optimum sensor location is
different for each application. The customer must evaluate conditions at the facility to make this
determination. In generally, experience suggests the device is more effective at detecting gas if
the following recommendations are followed:

• Mount sensor pointing down to prevent water build-up on the sensor head.

• Do not place sensor where contaminating substances may coat it.

• Although the Ultima MOS-5 Intelligent Sensor is RFI resistant, do not install sensor in

close proximity to radio transmitters or similar equipment.

• Locate the Ultima MOS-5 Intelligent Sensor where prevailing air currents contain the
maximum concentration of gas.

• Locate the Ultima MOS-5 Intelligent Sensor near possible sources of gas leaks.

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Ultima MOS-5 Detector

• Observe the Ultima MOS-5 Intelligent Sensor temperature specification and locate the
unit away from concentrated sources of heat.

• Install sensor in an area that is as free from wind, dust, water, shock, and vibration as
possible. See Section 0 for the environmental specifications of the unit. If dust and rain
cannot be avoided, we recommend the use of our splash guard (P/N 10395-1).

Sensors may be adversely affected by prolonged exposure to certain substances. Loss of
sensitivity or corrosion may be gradual if such agents are present in low concentrations or it
may be rapid at high concentrations. Examples of these substances are as follows:

• Silicones (often contained in greases and aerosols)

• Halides: compounds containing fluorine, chlorine, bromine and iodine

• Heavy metals, e.g. tetraethyl lead

• Caustic and Acidic liquids and vapors

• Glycol

The presence of contaminants in an area does not necessarily preclude the use of an Ultima
MOS-5 Intelligent Sensor. The feasibility of using a sensor in such areas must be determined
by an analysis of the specific factors in each application, and MSA should be consulted before
attempting any such installation.

Sensors used in these areas usually require more frequent calibration checks than normal, and
typically have a shorter life. In many such applications the standard 2-year warranty would not
apply.

IMPORTANT: Each H

Inside the cap is a desiccant. Do not remove this cap until the system is ready
to be powered. Save the cap and re-cap the sensor anytime the system power
is off for more than 1 hour.

WARNING: MSA discourages the painting of sensor assemblies. If the sensor head is

painted over, the gas will not be able to diffuse into the sensor. If the assembly
cover is painted over, the digital display cannot be read.

S sensor is shipped with a red plastic cap fitted over the sensor head.

2

3.3.1 Remote Mounting of the Sensor from the Electronics

If it is necessary to remotely mount the sensor from the electronics and the housing, the
maximum distance can be no greater than 3,700 feet (1,125) meters, using 14 AWG wire.
Sensors that are remotely mounted must be placed in an explosion-proof rated sensor
housing (P/N 10252-1), and the cable run must be contained in a conduit running from the
sensor housing to the electronics.

For remote mounting in Canada where the location is classified using the Zone classification
system, the sensors must be mounted in sensor housing B14-020. Only sensors 51457 can
be used in this configuration.

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Ultima MOS-5 Detector

3.4 Mounting and Wiring

WARNING: Unused cable entry holes must be sealed with an approved explosion-proof plug.

Red caps supplied by MSA are for dust protection only and must not be left on the

unit when installed.
WARNING: Conduits must be sealed within 18 inches of the enclosure.
The outline and mounting dimensions for the Ultima MOS-5 Intelligent Sensor (Figure 5) should

be used when making installation determinations. A complete list of the mechanical
specifications can be found in Section 9.3.2.

To prevent possible corrosion due to moisture or condensation, the conduit connected to the
Ultima MOS-5 Intelligent Sensor housing should be sealed or contain a drain loop.

NOTE: For ATEX and IECEx applications, conduit connections must only be made via suitably

certified ATEX (or IECEx as appropriate) conduit stopping boxes.

Information on Class I Division 1 and Zone 1 wiring methods can be found in the NEC or CEC.

Figure 5: Ultima MOS-5 Intelligent Sensor Outline and Mounting Dimensions, in inches

WARNING: Acetic acid will cause damage to metal components, metal hardware, ceramic

IC’s and other parts. If damage results from the use of a sealant that outgases
acetic acid (RTV silicone), the warranty will be void.

Once correctly installed, the Ultima MOS-5 Intelligent Sensor requires little or no maintenance,
other than periodic calibration checks to ensure system integrity. MSA recommends that a
schedule be established and followed.

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Ultima MOS-5 Detector

NOTE: The Ultima MOS-5 Intelligent Sensor full 2-year warranty will be voided if customer

personnel or third parties damage the Ultima MOS-5 Intelligent Sensor during repair
attempts.

Sensor heads exposed to the elements may require the accessory mounting threads to be
lubricated. Grease must not be used. As an alternate, PTFE (Teflon) tape may be used on
sensor accessory threads.

NOTE: Do not use any material or substance on threads that contact the sensor housing.

The removal of particulate matter from sensor accessories may be done through the use of an
appropriate halogen-free solvent. Water or ethanol is an example of a suitable solvent. The
accessories should be thoroughly dried, with compressed air if necessary, before refitting to the
sensor body.

3.5 Terminal Connections

The terminal blocks (TB) are located inside the housing and can be accessed by removing the
cover. A label on the inside of the housing cover provides details of all the terminal
connections.

Figure 6: Ultima MOS-5 Intelligent Sensor Terminal Block Locations

3.5.1 Terminal Block TB1 – Sensor Connections

TB1 contains the four sensor connections, white (W), black (B), red (R) and green (G). Remove
the display board by loosening the 2 captive screws on the board and lifting it straight up.
Connect the color-coded wires from the sensor to the matching colored terminals on TB1. The

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Ultima MOS-5 Detector

label on the inside of the cover can serve as a guide. Replace the display board by pressing it
into place and tightening the two captive screws.

WARNING: Do not connect +24 VDC to TB1. Damage to electronics or sensor may result.

3.5.2 Terminal Block TB2 – Power and Signal Connections

TB2 contains the connections for Power, Relay Reset, Remote Calibration, Modbus, and 0-20
mA Output Signal. The terminal connections are as follows:

TB2 position Function

1 0-20 mA Output
2 CH1 Modbus ­3 CH1 Modbus +
4 CH2 Modbus ­5 CH2 Modbus +
6 Remote Calibration
7 Relay Reset
8 Ground
9 +24 VDC Power

Table 1: TB2 Power and Signal Connections

It is recommended that a minimum three-wire shielded cable be used for making the power and
0-20mA Output connection on the Ultima MOS-5 Intelligent Sensor. It is also recommended
that separate two-wire shielded twisted pair cables be used for making the Modbus
connections. The spring type terminal block accepts 14 AWG to 20 AWG and the screw type
terminal block accepts 12 AWG to 18 AWG stranded or solid wire. Each wire should be
stripped before wiring the Ultima MOS-5 Intelligent Sensor. To connect wiring to the spring type
terminal block, insert a screwdriver into the orange tab and press down (Figure 7). Insert the
wire into the terminal and release the orange tab, clamping the wire in the terminal. Check the
hold of the wire by gently tugging it to ensure it is locked in. To connect wiring to the screw type
terminal block, loosen the top screw counterclockwise (Figure 8). Insert the wire into the
terminal and tighten the top screw clockwise. Check the hold of the wire by gently tugging it to
ensure it is locked in.

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Figure 7: Spring Type Terminal Block Operation

Ultima MOS-5 Detector

Figure 8: Screw Type Terminal Block Operation

Figure 9: Wire Strip Length

NOTE: Up to 12 AWG wire can be used if it is carefully striped. This applies only to a screw

type terminal connection (Figure 8).

3.5.3 DC Power and Ground Connections

• The customer must provide primary DC power.

Since the Ultima MOS-5 Intelligent Sensor is designed to operate continuously, a power switch
is not included, in order to prevent accidental system shutdown.

NOTE: Power must remain disconnected until all other wiring connections have been made.
See Section 9.3.3 for cable length specifications.

To connect +24 VDC to the Ultima MOS-5 Intelligent Sensor, connect the red wire (+24 VDC)
to TB2, position 9. Connect the ground or common wire to TB2, position 8.

3.5.4 Analog Signal Connections

The Ultima MOS-5 Intelligent Sensor Intelligent Transmitter provides a 4 to 20 mA output
signal. This signal can be sent to an industrial analog to digital converter, or logic solver.

The 4 to 20 mA signal provides for control room or other locations remote to the Ultima MOS-5
Intelligent Sensor to display indications of operation and alarm conditions.

To connect the 4 to 20 mA output signal with another unit, connect the wire into TB2, position 1,
labeled 4-20 mA OUT.

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