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MRLDS-250 Infrared Gas Detector 
Installation and Operation Manual

026-1315 Rev 4

Summary of Contents for MRLDS-250

Page 1: ...MRLDS 250 Infrared Gas Detector Installation and Operation Manual 026 1315 Rev 4 ...

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Page 4: ...Emerson 1065 Big Shanty Road NW Suite 100 Kennesaw GA 30144 USA Email SolutionsTechSup Emerson com 770 425 2724 www emerson com ...

Page 5: ...rigerated Spaces 6 2 2 4 Chillers 6 2 3 MOUNTING PROCEDURE 6 3 WIRING AND CONFIGURATION 8 3 1 OVERVIEW 8 3 2 WIRING SUPPLY POWER 24VAC OR 24VDC 8 3 3 WIRING ALARM OUTPUT ANALOG SIGNAL 9 3 4 WIRING THE DIGITAL ALARM OUTPUT RELAY 9 3 5 MODBUS NETWORK CONFIGURATION 10 3 6 FINISH INSTALLATION 11 4 OPERATION AND STABILIZATION 12 4 1 POWER UP AND WARMUP 12 4 2 STABILIZATION 12 4 3 PERFORM A MANUAL ZERO ...

Page 6: ...NT USING CALIBRATION GAS 22 7 MODBUS COMMUNICATIONS 24 7 1 INTRODUCTION 24 7 2 COMMUNICATIONS SETTINGS 24 7 3 ANALOG INPUT REGISTERS 24 7 4 ANALOG OUTPUT REGISTERS 25 7 5 INPUT STATUS FLAGS 26 7 6 OUTPUT STATUS FLAGS 26 8 TROUBLESHOOTING 27 8 1 FAULT CODES 27 8 2 DIAGNOSTIC ATTRIBUTES P 18 28 8 3 RESETTING THE MRLDS 250 TO DEFAULT VALUES 29 8 4 OTHER SYMPTOMS 29 9 REPLACEMENT PARTS AND ACCESSORIES...

Page 7: ... broadband gas detector P N 809 0030 is used as a general purpose gross leak detector and is factory tested and certified It is shipped from the factory with accuracy as shown in Table 1 1 gas dependent If more accurate detection is needed gas specific versions are available which are factory certified and calibrated to the target refrigerant The broadband gas detector combines refrigerants into 4...

Page 8: ...adjustment procedure detailed in Section 6 Functional Tests and Adjustments 2 MRLDS 250 Infrared Gas Detector I O Manual 026 1315 Rev 4 1See Section 5 Configure the Gas Detector for Information on Parameter 11 and other configuration instructions Figure 1 2 Broadband Gas Groups 1 4 ...

Page 9: ...09 0043 R513A 5 809 0044 R507 5 1See Section 5 Configure the Gas Detector for Information on Parameter 11 and other configuration instructions Figure 1 3 Gas Specific MRLDS 250 Gas Detectors NOTE Emerson recommends not re calibrating gas specific detectors in the field to a new target gas purchase a new gas specific detector instead In the event you prefer not to purchase a new gas specific detect...

Page 10: ...wn in Table 1 2 for the new target refrigerant 4 MRLDS 250 Infrared Gas Detector I O Manual 026 1315 Rev 4 1 3 Remote Controller Options The MRLDS 250 can connect to any controller through the standard analog output voltage and current see Table 1 4 for options the standard alarm relay or the digital Modbus RTU communications interface 1 4 Parts List Table 1 4 shows a list of components that are a...

Page 11: ...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 Default 0 IP Rating Not IP rated An accessory splash guard is available for areas requiring additional protection from wash down Response Time T90 T90 5 minutes Temperatur...

Page 12: ... Operation of any electrical equipment in such an environment constitutes a safety hazard CAUTION The MRLDS 250 contains sensitive electronic components that can be easily damaged Do not touch or disturb any of these components NOTE The mounting location of the monitor should allow it to be easily accessible for visual monitoring and servicing NOTE The gas detector must be connected to a marked su...

Page 13: ...rated Spaces In refrigerated spaces gas detectors should be located away from doors in the return airflow to the evaporators on a sidewall below head high is preferred or on the ceiling not directly in front of an evaporator nor in any direct airflow In large rooms with multiple evaporators gas detectors should be mounted on the central line between two adjacent evaporators as turbulence will resu...

Page 14: ... using two 6 screws provided through two of the 7 mounting holes and be careful not to over tighten the screws Refer to Figure 2 2 for the locations of mounting holes on the base For Junction Box Mount attach the MRLDS 250 base to the junction box using mounting hardware provided with your junction box through the two junction box holes Refer to Figure 2 2 for the locations of the two junction box...

Page 15: ...tional cable on the gland right have a 1 4 cable capacity each NOTE Install the optional cable gland in the right side of the base unit if needed Otherwise install the blanking plug that is included in the mounting kit 3 2 Wiring Supply Power 24VAC or 24VDC CAUTION Incorrect wiring may permanently damage the gas detector and void the warranty Double check all terminations before applying power Eit...

Page 16: ...is done electronically from the front panel display Connect two 18 to 20 AWG wires to terminal block positions 5 and 6 see Figure 3 4 noting ground and signal polarity per Table 3 2 Figure 3 4 Analog Output Wiring Table 3 2 Alarm Output Terminal Block Connections Function Pin Wiring Termination Analog 5 Analog output ground Output 6 Analog output signal The type of output signal on pins 5 and 6 is...

Page 17: ...m Output 10 Relay NC contact 11 Relay common contact 12 Relay NO contact 3 5 MODBUS Network Configuration If your application includes a MODBUS network make network connections RS 485 A and RS 485 B using 18 to 24 AWG shielded twisted pair wires with 120 ohm characteristic impedance to terminal block positions 7 and 8 Figure 3 6 noting inverted B and non inverted A signal connectors per Table 3 4 ...

Page 18: ...onditions NOTE Be sure to enable the termination resistor on the device at each end of the network See Figure 3 7 This includes the Building Management System if used CAUTION Care should be exercised when changing the terminator switch Before powering the gas detector use a fine pointed device or paper clip to slide the switch position Do not apply force to the switch or push on the switch with an...

Page 19: ...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 through 14 and or F 16 will prevent a manual zero from being performed NOTE A manual zero should be performed in the environment of operation and at the typical operating temperature NOTE Subsequent manual zeros may be performed provided ...

Page 20: ...rs when a non critical fault condition exists Table 4 2 MRLDS 250 Behavior During a Non Critical Fault Item Behavior During Alarm State Green LED Off indicating the gas detector is offline Display Shows the appropriate fault code Analog Output 4 20 mA output Changes to 2 mA 1 5V output Changes to 0 5V 2 10V output Changes to 1 0V Modbus Registers Modbus registers indicate the fault 4 5 3 Critical ...

Page 21: ... parameter displayed When pressed together and held for five seconds this key combination manually zeros the gas detector Saves the currently displayed parameter to memory 5 2 Setting Parameters 5 2 1 Overview Press and hold the information button for five seconds to activate the parameter list Each parameter is shown in turn by using the UP or DOWN buttons The parameter is shown as P XX with XX b...

Page 22: ...alarm occurs failsafe is simply inverted This allows power failures to be detected as alarms 00 NO default mode 01 Failsafe mode Parameter Description Table 5 2 Parameter Numbers Names and Descriptions Relay Latching Controls the relay latching behavior 00 OFF default Relay does not latch and resets once the alarm condition is removed 01 ON Relay remains latched reset by BMS command by pressing an...

Page 23: ...us RS 485 communications 00 9 600 baud default Parameter Description Table 5 2 Parameter Numbers Names and Descriptions Stop Bits Sets the number of stop bits required to match the controlling communications equipment for example 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 Analog Output Scaling Al...

Page 24: ...ough the following CAL is displayed briefly Next the gas group number or gas type based on product code is displayed Then four dashes are displayed After gas is applied and the 75 PPM squelch level is exceeded the live concentration replaces the four dashes See Section 6 4 Adjustment Using Calibration Gas if using Gas Test Mode to initiate the calibration procedure NOTE To prevent false alarms all...

Page 25: ...a reset This returns the gas detector to an uncalibrated condition See parameter P 17 for information on how to recalibrate the gas detector See Section 9 Replacement Parts and Accessories for a complete list of codes and details on the reset option Parameter Description Table 5 2 Parameter Numbers Names and Descriptions Response Filtering This parameter is used to turn filtered output ON 01 or OF...

Page 26: ... WARNING Failure to test or adjust the unit in accordance with applicable instructions and with industry guidelines may result in serious injury or death The manufacturer is not liable for any loss injury or damage arising from improper testing incorrect adjustment or inappropriate use of the unit WARNING Before testing the gas detectors on site the MRLDS 250 must be powered up and allowed to stab...

Page 27: ...onnect as instructed by the customer For bump test or calibration the MRLDS 250 should be powered up and fully stabilized see Section 4 Operation and Stabilization 6 3 Bump Testing WARNING Notify others that testing is underway During bump testing the alarm outputs are active and will trigger the intended response It is the operator s responsibility to ensure that such actions are acceptable and c...

Page 28: ...ur dashes are displayed After gas is applied and the 75 PPM squelch level is exceeded the live 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...

Page 29: ...ector 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 that is achievable Step Adjustment Using Calib...

Page 30: ...eld is received by all detectors regardless of the address selected to enable the master device to broadcast simultaneously to all the detectors Refer to the specifications section for information on RS 485 network communications parameters such as data bits stop bits and more 7 3 Analog Input Registers Analog input registers are read only and use function code 04 Table 7 1 Analog Input Registers ...

Page 31: ... 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 4 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 number 1 to 4 broadband uni...

Page 32: ...d 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 7 4 Output Status Flags Reg Description Range P 4000 Buzzer flag 0 or 1 ON 0 Off 1 On 4001 Test required If operating...

Page 33: ...lts in the gas detector no longer monitoring its surroundings for refrigerant The fault number is displayed and the power LED is turned off indicating that the gas detector is offline The critical fault range is F 09 to F 16 If any of these faults occur first try to clear the faults by cycling power to the sensor The easiest way to do this is by removing the sensor from the base and reattaching If...

Page 34: ...icates a gas detector error Input Voltage Fault 0x00 80 Input supply power to the MRLDS 250 is out of range i e 24V 20 IMPORTA NT If this fault is active the gas detector is offline and not monitoring Correct the input supply voltage to restore normal operation Critical Faults Criticalfault Cycle power to the sensor andseeofthe fault clears If not contact Emerson technical support for additional g...

Page 35: ...WN buttons for 5 seconds This will cause the following to occur All the LED segments will then light for 3 seconds The gas detector resets to the default settings The gas detector beeper sounds for 3 seconds 3 After 3 seconds the user is returned 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...

Page 36: ... Calibrated to R448A 809 0042 Gas Detector Module Calibrated to R449A 809 0043 Gas Detector Module Calibrated to R513A 890 0044 Gas Detector Module Calibrated to R507 603 1100 Splash Guard Kit Accessory Provides additional protection for wash down or impact Includes mounting hardware for attaching to walls NOTE The gas detector response time will lengthen when the Splash Guard is used The installe...

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Page 40: ...Inc and or its affiliates collectively Emerson reserves the right to modify the designs or specifications of such products at any time without notice Emerson does not assume responsibility for the selection use or maintenance of any product Responsibility for proper selection use and maintenance of any product remains solely with the purchaser and end user 026 1315 Emerson is a trademark of Emerso...

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