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MGS-250 Manual 

 

 

20 

6490-9000 Revision 3 

Step 

Mounting Procedure 

Wall Mount 

Attach the MGS-250 base to 
the mounting surface using 
two #6 screws (provided) 
through two of the mounting 
holes, being careful not to 
over-tighten the screws.  
Refer to Figure 6 for the 
locations of mounting holes on 
the base. 

Junction Box Mount 

Attach the MGS-250 base to 
the junction box (using 
mounting hardware provided 
with your junction box) 
through the two junction box 
holes.  Refer to Figure 6 for 
the locations of the two 
junction box mounting holes 
on the base. 

Unless you are ready to wire the device (see section 3), 
carefully snap the cover onto the base unit. 

 

 

Figure 5.  Initial Housing Separation 

Summary of Contents for 6401-0500

Page 1: ...Infrared Gas Detector Installation and Operation Manual Instruction 6490 9000 June 2015 Revision 3 Product Leadership Training Service Reliability ...

Page 2: ...GHT TO CHANGE SPECIFICATIONS WITHOUT NOTICE THE INFORMATION CONTAINED HEREIN IS BASED ON DATA CONSIDERED ACCURATE HOWEVER NO WARRANTY IS EXPRESSED OR IMPLIED REGARDING THE ACCURACY OF THIS DATA ALL GOODS MUST BE SHIPPED TO THE MANUFACTURER BY PREPAID FREIGHT ALL RETURNED GOODS MUST BE PRE AUTHORIZED BY OBTAINING A RETURN MERCHANDISE AUTHORIZATION RMA NUMBER CONTACT THE MANUFACTURER FOR A NUMBER AN...

Page 3: ... OR IN PART IN ANY MANNER OR FORMAT WITHOUT THE WRITTEN PERMISSION OF BACHARACH INC ALL SOFTWARE WHICH BACHARACH UTILIZES AND OR DISTRIBUTES HOLDS A PROPRIETARY INTEREST AND IS ALSO SUBJECT TO COPYRIGHT PROTECTION AND ALL RIGHTS ARE RESERVED NO PARTY MAY USE OR COPY SUCH SOFTWARE IN ANY MANNER OR FORMAT EXCEPT TO THE EXTENT THAT BACHARACH GRANTS THEM A LICENSE TO DO SO IF THIS SOFTWARE IS BEING LO...

Page 4: ...MGS 250 Manual 4 6490 9000 Revision 3 ...

Page 5: ...2 2 2 Machinery Rooms 18 2 2 3 Refrigerated Spaces 18 2 2 4 Chillers 19 2 3 Mounting Procedure 19 SECTION 3 WIRING AND CONFIGURATION 22 3 1 Overview 22 3 2 Wiring Supply Power 24VAC or 24VDC 23 3 3 Wiring Alarm Output Analog Signal 25 3 4 Wiring the Digital Alarm Output Relay 26 3 5 Modbus Network Configuration 27 3 6 Conclusion 29 SECTION 4 OPERATION AND STABILIZATION 30 4 1 Power Up and Warmup 3...

Page 6: ...ng 45 6 4 Adjustment Using Calibration Gas 46 SECTION 7 MODBUS COMMUNICATIONS 49 7 1 Introduction 49 7 2 Communications Settings 49 7 3 Analog Input Registers 50 7 4 Analog Output Registers 51 7 5 Input Status Flags 52 7 6 Output Status Flags 52 SECTION 8 TROUBLESHOOTING 53 8 1 Fault Codes 53 8 2 Diagnostics Attributes P 18 55 8 3 Resetting MGS 250 to Default Values 56 8 4 Other Symptoms 57 SECTIO...

Page 7: ...MGS 250 Base 21 SECTION 3 WIRING AND CONFIGURATION 22 Figure 7 Terminal Blocks and Cable Glands 22 Figure 8 Supply Power Wiring Options 23 Figure 9 Maintaining Neutral Polarity 24 Figure 10 Analog Output Wiring 25 Figure 11 Sample Relay Output Wiring 26 Figure 12 Modbus Network Wiring 27 Figure 13 Setting Network Termination Resistors 29 SECTION 5 CONFIGURE THE GAS DETECTOR 33 Figure 14 The User I...

Page 8: ... 4 OPERATION AND STABILIZATION 30 Table 9 MGS 250 Behavior during Alarm Conditions 31 Table 10 MGS 250 Behavior during a Non Critical Fault 32 Table 11 MGS 250 Behavior during a Critical Fault 32 SECTION 5 CONFIGURE THE GAS DETECTOR 33 Table 12 Button Functions 33 Table 13 Parameter Numbers Names and Descriptions 34 SECTION 7 MODBUS COMMUNICATIONS 49 Table 14 Analog Input Registers 50 Table 15 Ana...

Page 9: ... fixed gas detector which can detect a wide range of refrigerant gases The MGS 250 can be used on a stand alone basis or integrated into controls or a Building Management System BMS The MGS 250 can be used in locations that require continuous monitoring and to add gas detection solutions to an existing system Figure 1 MGS 250 Components ...

Page 10: ...ed and calibrated to the target refrigerant The broadband gas detector combines refrigerants into three groups shown in Figure 2 Measurement performance is based on an average response profile for all of the gases within the group NOTE Greater accuracy may be achieved through the use of calibration gas and the adjustment procedure detailed in Section 6 Table 1 Broadband Gas Groups and Performance ...

Page 11: ...vision 3 11 Figure 2 Broadband Gas Groups 1 3 1 2 3 Detecting Specific Gases Each gas specific gas detector PNs 6401 0501 to 6401 0515 is shipped factory calibrated to its specific target refrigerant Refer to Figure 3 and Table 2 ...

Page 12: ...MGS 250 Manual 12 6490 9000 Revision 3 Figure 3 Gas Specific MGS 250 Gas Detectors ...

Page 13: ...R422a 5 6401 0510 R422d 5 6401 0511 R427a 3 6401 0512 R507 5 6401 0513 HFO1234YF 5 6401 0514 HFO1234Ze 5 6401 0515 HFO1233ZD 5 1 See Section 5 for information on Parameter 11 and other configuration instructions NOTE Gas specific detectors can be re calibrated in the field to new target gases Use optional calibration instructions in Chapter 6 for increased accuracy when detecting a new target gas ...

Page 14: ...n section 5 2 If changed the gas detector will have a lower accuracy for the target refrigerant without calibration In this example that accuracy is 16 of reading Optional Recalibration For Improved Accuracy By applying calibration gas containing the new target refrigerant and via the routine described in Section 6 4 the gas detector may then be adjusted to respond with the calibrated accuracy of ...

Page 15: ...with your order Table 3 Parts List Part Number Description Various Depends on Model Ordered 6401 0500 MGS 250 Broadband 6401 0501 MGS 250 R22 6401 0502 MGS 250 R123 6401 0503 MGS 250 R134a 6401 0504 MGS 250 R404a 6401 0505 MGS 250 R407a 6401 0506 MGS 250 R407c 6401 0507 MGS 250 R407f 6401 0508 MGS 250 R410a 6401 0509 MGS 250 R422a 6401 0510 MGS 250 R422d 6401 0511 MGS 250 R427a 6401 0512 MGS 250 R...

Page 16: ...te 9 600 or 19 200 selectable Start bits 1 Data bits 8 Parity None odd even programmable Stop bits 1 or 2 programmable Retry time 500 ms min time between retries End of msg Silent 3 5 characters Alarm Delay Selectable 0 to 15 minutes IP Rating Not IP rated An accessory splash shield is available for areas requiring additional protection from wash down Response Time T90 5 minutes Temperature Rating...

Page 17: ...ted to a marked suitably located and easily reached switch or circuit breaker as means of disconnection NOTE Connect monitor power and signaling terminals using wiring that complies with local electrical codes or regulations for the intended application CAUTION Do NOT mount the MGS 250 directly to vibrating machinery as the vibrations may degrade the gas detector s performance 2 2 Mounting Locatio...

Page 18: ...ed as near as possible to the most likely sources of leakage such as the compressor expansion valves mechanical joints or cable duct trenches o Perimeter Detection where gas detectors completely surround the area or equipment Halocarbon and hydrocarbon refrigerants are heavier than air gases and as such the gas detectors should be located near ground level 6 to 18 inches from the floor NOTE Gas de...

Page 19: ...p latch While pushing the latch grasp the back edge of the housing near the latch and pull the back away When mounted the housing is simply opened by pressing the top latch with a suitable screwdriver or other flat blade With the top latch depressed pull the housing apart by grasping the sides and pulling straight out With the housing separated the mounting base with terminal blocks will be visibl...

Page 20: ... to Figure 6 for the locations of mounting holes on the base Junction Box Mount Attach the MGS 250 base to the junction box using mounting hardware provided with your junction box through the two junction box holes Refer to Figure 6 for the locations of the two junction box mounting holes on the base 4 Unless you are ready to wire the device see section 3 carefully snap the cover onto the base uni...

Page 21: ...MGS 250 Manual 6490 9000 Revision 3 21 Figure 6 Front and Back Views of MGS 250 Base ...

Page 22: ... detector enclosure by pressing the top latch with a suitable screwdriver or other flat blade With the top latch depressed pull the housing apart by grasping the sides and pulling straight out Align and press together to close Figure 7 Terminal Blocks and Cable Glands NOTE The pre installed cable gland left and optional cable gland right have a cable capacity each NOTE Install the optional cable g...

Page 23: ...r 24VAC or 24VDC may be used to power the MGS 250 Connect wiring to the appropriate terminal locations see Table 5 Use 2 wires between 14 and 22 AWG Refer to Figure 8 for AC wiring left or DC wiring right Figure 8 Supply Power Wiring Options Table 5 Power Options and Terminal Block Connections Power Option Pin Label Wiring Termination 24 VAC 1 L 24V AC line 2 N 24V AC neutral 24 VDC 3 24V DC posit...

Page 24: ... certified power supply that is isolated from line voltage by double insulation or an appropriately rated UL listed CSA Class 2 transformer Failure to comply can result in personal injury or death WARNING Neutral polarity must be maintained across units Refer to Figure 9 Figure 9 Maintaining Neutral Polarity ...

Page 25: ...electronically from the front panel display Connect two 18 to 20 AWG wires to terminal block positions 5 and 6 see Figure 10 noting ground and signal polarity per Table 6 Figure 10 Analog Output Wiring Table 6 Alarm Output Terminal Block Connections Function Pin Wiring Termination Analog Output 5 Analog output ground 6 Analog output signal The type of output signal on pins 5 and 6 is programmable ...

Page 26: ...current alarm status Figure 11 Sample Relay Output Wiring NOTE The relay can be programed to be failsafe normally energized By default the relay is set to be normally de energized This can be set using parameter P 06 Make relay connections NO NC or both using 18 to 20 AWG wires to terminal block positions 10 11 and 12 see Figure 11 noting normally open normally closed and common connectors per Tab...

Page 27: ... terminal block positions 7 and 8 see Figure 12 noting inverted B and non inverted A signal connectors per Table 8 Figure 12 Modbus Network Wiring Table 8 Modbus Network Communications Connections Function Pin Wiring Termination Modbus Network Communications 7 RS 485 B inverted 8 RS 485 A non inverted 9 RS 485 shield IMPORTANT For Modbus network communications wiring use only 18 24 AWG shielded tw...

Page 28: ...t System are configured similarly If the MGS 250 is at the end of the RS 485 network then be sure to set the RS 485 terminator on the printed circuit board PCB to IN This applies a terminating resistor to the end of the wires per the requirements of the RS 485 protocol The terminator should be set to OUT for all other installation conditions IMPORTANT Be sure to enable the termination resistor on ...

Page 29: ...ing all electrical connections Ensure the top and bottom snap locks are engaged IMPORTANT If the right cable gland was not needed during installation and wiring be sure to install the blanking plug IMPORTANT Do not apply caulking or other material around the gas detector base The gas detector relies on air exchange through the spaces between the base and the gas detector housing Do not obstruct th...

Page 30: ...his stabilization period to 3 hours for freezer applications To manually zero the gas detector press and hold the UP and DOWN buttons simultaneously for 5 seconds The gas detector will beep and the display will show zEro when zeroing is complete The display will show fAiL if the temperature is changing too quickly or there is an active alarm condition Additionally certain system faults F 08 F 10 t...

Page 31: ...ation etc NOTE The alarm feature includes a 20 dead band to prevent alarm chatter if the concentration hovers near the alarm setpoint Once the alarm has been triggered it will remain latched until the concentration drops below 80 of the alarm setpoint 4 5 Gas Detector Faults 4 5 1 Overview There are two levels of fault monitoring built into the gas detector Non critical Critical 4 5 2 Non Critical...

Page 32: ...Critical faults may indicate an unrecoverable condition Please refer to Section 8 for more information The following occurs when a critical fault condition exists Table 11 MGS 250 Behavior during a Critical Fault Item Behavior During Critical Fault State Green LED Off indicating the gas detector is off line Display Shows the appropriate fault code Analog Output 4 20 mA output Changes to 2 mA 1 5 V...

Page 33: ...play is off press any button to wake the display for 10 seconds Buttons functions are listed in Table 12 Table 12 Button Functions Button Description Used to access the parameter list Used to back up one level without writing to memory when the parameter list is active Used to mute the audible alarm for the time period configured in parameter P 12 Used to increment the value or parameter displayed...

Page 34: ... the setting 5 2 2 Configuration Parameters Table 13 Parameter Numbers Names and Descriptions Parameter Description Maintenance Mode Sets gas detector to offline mode for 30 minutes 00 Gas detector is online with normal response to its surroundings default 01 Gas detector is offline and suppresses all outputs Display reads oFFL offline during 30 minute timeout Alarm Setpoint Sets desired PPM value...

Page 35: ...rgizing when an alarm condition occurs default to energizing at power up Failsafe In both cases the relay changes state when an alarm occurs failsafe is simply inverted This allows power failures to be detected as alarms 00 NO default mode 01 Failsafe mode Relay Latching Controls the relay latching behavior 00 OFF default Relay does not latch and resets once the alarm condition is removed 01 ON Re...

Page 36: ...ection Selects either gas group number for broadband operation or specific gas name for gas specific mode Broadband Select from 3 groups of gases 1 R134a R404a R407a R407c R407f R427a R507 HFO1233ZD 2 R422a R422d HFO1234YF and HFO1234Ze 3 R22 by itself Specific Gas The actual refrigerant name is shown Select the appropriate refrigerant NOTE Gas specific detectors are factory calibrated to a single...

Page 37: ...fter Modbus register 4000 is set to 0 Baud Rate Sets the baud rate for Modbus RS 485 communications 00 9 600 baud default 01 19 200 baud Stop Bits Sets the number of stop bits required to match the controlling communications equipment e g building management system etc 01 1 stop bit default 02 2 stop bits Parity Sets Modbus parity option 00 None default 01 Odd parity 02 Even parity ...

Page 38: ... scale the alarm setting NOTE When the ppm level is greater than the programmed analog output Full Scale ppm P 16 the analog output will go to a 10 over range state indicating that the concentration is too high for the analog output to achieve For example for a 1 5 V setting the analog output would go to 5 5 V for 4 20 mA it would go to 22 mA and so on NOTE The analog output signal range is from 1...

Page 39: ...MGS 250 Manual 6490 9000 Revision 3 39 Figure 15 Analog Output Scaling Options ...

Page 40: ...h level is exceeded the live concentration replaces the four dashes See section 6 4 if using Gas Test Mode to initiate the calibration procedure NOTE To prevent false alarms all outputs are suspended while Test Mode is active The only live indication is the 4 digit display Once the gas test mode is enabled to perform a gas test or calibration the unit will automatically go offline for a ten minute...

Page 41: ...A 10 A 17 Factory Use Only To aid in troubleshooting the operator may choose to reset the gas detector to its default state by holding both the UP and DOWN buttons for 5 seconds while in the Diagnostics Menu All settings including the alarm setpoint gas adjustments the selected gas curve calibration data the Modbus address etc revert to specific default values after a reset IMPORTANT Calibrations ...

Page 42: ...via Modbus and the analog output terminals NOTE The detector display is OFF when filtering is OFF P 09 is disabled NOTE Whenever filtering is OFF the detector display will turn ON for 10 minutes if the detector is re zeroed see Section 4 3 This is intended to aid maintenance testing The analog outputs continue to transmit the full unfiltered range and the alarm setpoint remains active NOTE If filt...

Page 43: ...be extended based on application but should never exceed 2 years CAUTION In applications where life safety is critical calibration gas adjustment should be done quarterly every 3 months or on a more frequent basis Bacharach is not responsible for setting safety practices and policies Safe work procedures including calibration policies are best determined by company policy industry standards and lo...

Page 44: ...The frequency and nature of testing or calibration may be determined by local regulation or standards EN378 and the F GAS Regulation require an annual check in accordance with the manufacturer s recommendation 6 2 Bump Testing vs Adjusting Detector Response There are two concepts that need to be differentiated bump test gas detector response adjustment A bump test exposes the gas detector to a gas...

Page 45: ... 3 Bump Testing IMPORTANT Notify others that testing is underway During bump testing the alarm outputs are active and will trigger whatever response is intended It is the operator s responsibility to ensure that such actions are acceptable and can be performed safely After installation and parameter setup see Section 5 the units should be bump tested Expose the gas detector to test gas The gas sel...

Page 46: ... gas detector to gas from the cylinder Monitor the LED display reading Refer to the specifications section for acceptance criteria Figure 16 Using Calibration Gas 6 4 Adjustment Using Calibration Gas Adjustment Using Calibration Gas requires a gas cylinder with the appropriate gas and concentration Note that Bacharach offers a calibration kit that consists of a calibration gas cylinder and a flow ...

Page 47: ...ive concentration replaces the four dashes NOTE The analog outputs relay activity and RS 485 ppm reporting are suspended in Gas Test Mode to prevent false alarms 3 Expose the gas detector to gas from the cylinder Monitor the 4 digit LED display reading 4 Wait for the ppm reading to stabilize This should take approximately 4 6 minutes Minor changes less than 5 ppm in 10 seconds are considered stabl...

Page 48: ...Upon exiting the parameters list the gas detector will enter offline mode for a period of 10 minutes This allows time for the calibration gas to dissipate after testing During offline mode the gas detector suppresses all outputs The display reads oFFL offline during 10 minute timeout NOTE All calibration gas mixtures have a blend tolerance The tolerance will limit the actual adjustment accuracy th...

Page 49: ...bus protocol Generally with the exception of some of the communications parameters parameters you can access and or configure from the front panel of the MGS 250 can also be accessed and or configured via a Building Management System for example on the same Modbus network 7 2 Communications Settings There are 255 selections available to be set electronically from addresses 1 to 255 inclusive Modbu...

Page 50: ...nge Units P 1000 Concentration gas level 0 100 FS 1001 Concentration gas level 0 65 535 ppm 1002 Reserved 1003 Full scale detector level 0 65 535 ppm 1004 Alarm set point full scale 0 100 1005 Gas detector timer 0 65 535 hours 1006 Node address 1 247 none P 10 1007 Software version none 1008 Reserved 1009 Reserved 1010 Reserved 1011 Reserved 1012 16 bit fault code 0 65535 none ...

Page 51: ...59 min P 12 2003 Alarm OFF delay 0 15 min P 05 2004 Relay action 0 NO 1 Failsafe none P 06 2005 Relay latching enable 0 Disable 1 Enable none P 07 2006 Buzzer enable 0 Disable 1 Enable none P 08 2007 Display mode 0 Off 1 On none P 09 2008 Analog output type 0 0 5 V 1 1 5 V 2 0 10 V 3 2 10 V 4 4 20 ma none P 03 2009 Baud rate 0 9600 1 19200 none P 13 2010 Stop bits 1 or 2 none P 14 2011 Gas curve n...

Page 52: ...r 1 fault 0 1 3003 Red LED state 0 or 1 ON 0 1 3004 Green LED state 0 or 1 powered on 0 1 3005 Reserved 3006 Start up 0 normal operation 1 warming up 0 1 3007 Reserved 3008 Reserved 7 6 Output Status Flags Output Status Flags are readable using function code 01 and writable using function code 05 Table 17 Output Status Flags Reg Description Range P 4000 Buzzer flag 0 or 1 ON 0 Off 1 On 4001 Test r...

Page 53: ...cal faults is a matter of waiting for the environmental conditions to return to a more typical condition correcting wiring mistakes or in some cases relocating the gas detector For example placing the gas detector near a forced air heater may cause temperature faults The non critical fault range is F 01 to F 08 Critical faults indicate a functional problem that results in the gas detector no longe...

Page 54: ...en Loop Fault 0x0010 Possible wiring connection and or termination issue exists When analog output type is 4 20ma and loop is open use 18 24AWG shielded twisted pair with 120 ohm characteristic impedance for Modbus connections Modbus Fault 0x0020 Modbus message was truncated or timed out early PPM Over range Fault 0x0040 PPM exceeds 9999 This may indicate a very large gross leak If no leak is pres...

Page 55: ...scription Displays the current fault condition code in hex format 0000 no faults are active XXXX HEX number See Table 18 for the HEX format cross reference Displays a hex format code that corresponds to any faults that occurred since the internal fault record was last erased See Table 18 for the HEX format cross reference The records may be erased by pressing the ENTER button Displays the number o...

Page 56: ...tments selected gas curve calibration data Modbus address etc revert to specific default values after a reset The broadband sensor option P N 6401 0500 resets to gas group 1 Gas specific products P Ns 6401 0501 through 6401 0515 are reset to the R134a gas curve IMPORTANT Calibrations on either gas specific or broadband models are lost after a reset This returns the gas detector to an uncalibrated ...

Page 57: ...d to the parameter list at parameter P 18 4 The gas detector may now be re programmed for further troubleshooting if needed 8 4 Other Symptoms Other common wiring problems can also cause the gas detector to malfunction Check below for additional conditions that will cause gas detector issues Table 20 Other Symptoms and Possible Causes Symptom Possible Cause s Green power LED off Check power supply...

Page 58: ...ibrated 1 6400 0022 Gas Detector Module R407f Calibrated 1 6400 0023 Gas Detector Module R410a Calibrated 1 6400 0024 Gas Detector Module R422a Calibrated 1 6400 0025 Gas Detector Module R422d Calibrated 1 6400 0026 Gas Detector Module R427a Calibrated 1 6400 0027 Gas Detector Module R507 Calibrated 1 6400 0028 Gas Detector Module HFO1234YF Calibrated 1 6400 0029 Gas Detector Module HFO1234ZE Cali...

Page 59: ...bility EMC Directive 2006 65 EC Low Voltage Directive LVD Standard s EN 50270 2006 Electromagnetic compatibility electrical apparatus for the detection and measurement of combustible gases toxic gases or oxygen EN 55011 2007 Limits and methods of measurement of electromagnetic disturbance characteristics of industrial scientific and medical ISM radio frequency equipment IEC 61010 1 2010 EN 61010 1...

Page 60: ...anual 60 6490 9000 Revision 3 www MyBacharach com help MyBacharach com Bacharach World Headquarters USA 621 Hunt Valley Circle New Kensington PA 15068 Phone 724 334 5000 Toll Free 1 800 736 4666 Fax 724 334 5001 ...

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