Infrared Gas Detector Installation and Operation Manual Instruction 6490-9000 February 2014 Revision 1 Product Leadership • Training • Service • Reliability
MGS-250 Manual WARRANTY POLICY BACHARACH, INC. WARRANTS THIS GAS DETECTOR TO BE FREE FROM DEFECTS IN MATERIALS AND WORKMANSHIP FOR A PERIOD OF ONE YEAR FROM THE DATE OF PURCHASE BY THE ORIGINAL OWNER. IF THE PRODUCT SHOULD BECOME DEFECTIVE WITHIN THIS WARRANTY PERIOD, WE WILL REPAIR OR REPLACE IT AT OUR DISCRETION. THE WARRANTY STATUS MAY BE AFFECTED IF THE GAS DETECTOR HAS NOT BEEN USED AND MAINTAINED PER THE INSTRUCTIONS IN THIS MANUAL OR HAS BEEN ABUSED, DAMAGED, OR MODIFIED IN ANY WAY.
MGS-250 Manual POLICY OF PERFORMING ALL NEEDED REPAIRS TO RESTORE THE GAS DETECTOR TO FULL OPERATING CONDITION. PRIOR TO SHIPPING EQUIPMENT TO BACHARACH OR MURCO, CONTACT OUR OFFICE FOR AN RMA # (RETURN MERCHANDISE AUTHORIZATION). ALL RETURNED GOODS MUST BE ACCOMPANIED BY AN RMA NUMBER. PACK THE EQUIPMENT WELL (IN ITS ORIGINAL PACKING IF POSSIBLE), AS BACHARACH CANNOT BE HELD RESPONSIBLE FOR ANY DAMAGE INCURRED DURING SHIPPING TO OUR FACILITY.
MGS-250 Manual 4 6490-9000 Revision 1
MGS-250 Manual Table of Contents SECTION 1. INTRODUCTION ........................................................................ 9 1.1. Overview ...................................................................................................... 9 1.2. Detection Options ...................................................................................... 10 1.2.1. Broadband vs. Gas Specific .............................................................. 10 1.2.2. Broadband Gas Detection ..............
MGS-250 Manual 5.2. Setting Parameters..................................................................................... 34 5.2.1. Overview .......................................................................................... 34 5.2.2. Configuration Parameters ................................................................ 34 5.3. Completing Setup ....................................................................................... 42 SECTION 6. 6.1. 6.2. 6.3. 6.4. Introduction .................
MGS-250 Manual List of Figures SECTION 1. Figure 1. Figure 2. Figure 3. Figure 4. INTRODUCTION ........................................................................ 9 MGS-250 Components ......................................................................... 9 Broadband Gas Groups 1-3 ................................................................ 11 Gas Specific MGS-250 Gas Detectors ................................................. 12 Changing Gas Types and Accuracy ...............................
MGS-250 Manual List of Tables SECTION 1. INTRODUCTION ........................................................................ 9 Table 1: Broadband Gas Groups and Performance (P/N 6401-0500) ................ 10 Table 2: Gas Specific Detector Measurement Performance .............................. 13 Table 3: Parts List ............................................................................................... 15 Table 4: Technical Specifications ........................................................
MGS-250 Manual Section 1. Introduction 1.1. Overview The MGS-250 NDIR (non-dispersive infrared) is a state-of-the-art 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 Manual 1.2. Detection Options 1.2.1. Broadband vs. Gas Specific The MGS-250 NDIR refrigerant gas detectors are available in two versions: broadband and gas specific. 1.2.2. Broadband Gas Detection The broadband gas detector (P/N 6401-0500) 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 (gas dependent).
MGS-250 Manual Figure 2. Broadband Gas Groups 1-3 1.2.3. Detecting Specific Gases Each gas-specific gas detector (PNs 6401-0501 to 6401-0514) is shipped factory calibrated to its specific target refrigerant. Refer to Figure 3 and Table 2.
MGS-250 Manual Figure 3.
MGS-250 Manual Table 2: Gas Specific Detector Measurement Performance 1 1 Part Number Refrigerant 6401-0501 6401-0502 6401-0503 6401-0504 6401-0505 6401-0506 6401-0507 6401-0508 6401-0509 6401-0510 6401-0511 6401-0512 6401-0513 6401-0514 R22 R123 R134a R404a R407a R407c R407f R410a R422a R422d R427a R507 HFO1234YF HFO1234Ze Accuracy ±30 ppm ±5% ±30 ppm ±5% ±30 ppm ±5% ±30 ppm ±5% ±30 ppm ±3% ±30 ppm ±3% ±30 ppm ±3% ±30 ppm ±3% ±30 ppm ±5% ±30 ppm ±5% ±30 ppm ±3% ±30 ppm ±5% ±30 ppm ±5% ±30 ppm ±5% S
Optional Recalibration (For Improved Accuracy) Changed Gas Type (Reduced Accuracy) As Shipped MGS-250 Manual Part number 6401-0501 (R22) is factory calibrated to R22 and has an as-shipped R22 response accuracy of ±30 ppm ±5% of reading. The gas detector may be changed to respond to any of the other listed refrigerants (see parameter P.-11, in section 5.2). If changed, the gas detector will have a lower accuracy for the target refrigerant (without calibration).
MGS-250 Manual 1.3. Remote Controller Options The MGS can connect to any controller through the standard analog output (voltage and current; see Table 4 for options), the standard alarm relay, or the digital Modbus RTU communications interface. 1.4. Parts List Table 3 shows a list of components that are shipped with your order.
MGS-250 Manual 1.5. Specifications Table 4: Technical Specifications Specification Description Power Supply 24 VDC, 24 VAC 50/60 Hz, 2.5 W max Power Monitoring Green LED Visual Alarm Red 4-digit LED display Audible Alarm Buzzer (audible alarm), enable/disable Fault Monitoring Fault codes presented to user Analog Outputs 4-20 mA; 0-5 V; 0-10 V; 1-5 V; 2-10 V Relay 1 relay rated 1 A @ 24 VAC/VDC (0.
MGS-250 Manual Section 2. Mounting the Gas Detector 2.1. Warnings and Prerequisites WARNING: Explosion hazard! Do not mount the MGS-250 in an area that may contain flammable liquids, vapors, or aerosols. Operation of any electrical equipment in such an environment constitutes a safety hazard. CAUTION: The MGS-250 contains sensitive electronic components that can be easily damaged. Do not touch or disturb any of these components.
MGS-250 Manual 2.2.2. Machinery Rooms There is no absolute rule in determining the number of gas detectors and their locations. However, a number of simple guidelines will help to make a decision. Gas detectors monitor a point as opposed to an area. If the gas leak does not reach the detector then no alarm will be triggered. Therefore, it is extremely important to carefully select the gas detector location. Also consider ease of access for maintenance.
MGS-250 Manual 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 2 adjacent evaporators, as turbulence will result in airflows mixing. 2.2.4. Chillers In the case of small water- or air-cooled enclosed chiller units mount the gas detector so as to monitor airflow to the extract fans.
MGS-250 Manual Step Mounting Procedure 3 Wall Mount Attach the MGS-250 base to the mounting surface using two #6 screws (provided) through two of the 7 mounting holes, being careful not to over-tighten the screws. Refer to Figure 6 for the locations of mounting holes on the base. 4 Unless you are ready to wire the device (see section 3), carefully snap the cover onto the base unit.
MGS-250 Manual Figure 6.
MGS-250 Manual Section 3. Wiring and Configuration 3.1. Overview Prior to wiring and configuring the MGS-250, assure the following conditions have been met: • • MGS-250 backplate is mounted in an appropriate location the cover panel is removed. If the cover panel was reattached after mounting, open the gas 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.
MGS-250 Manual 3.2. Wiring Supply Power (24VAC or 24VDC) WARNING: Incorrect wiring may permanently damage the gas detector, and void the warranty. Double check all terminations before applying power. Either 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.
MGS-250 Manual WARNING: The MGS-250 must be powered by either: • • a suitable UL 60950/CSA 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.
MGS-250 Manual 3.3. Wiring Alarm Output (Analog Signal) The MGS-250 provides an analog output signal that is proportional to the level of gas detected. NOTE: No jumpers or hardware switch settings are required to configure the analog output. This is done 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.
MGS-250 Manual 3.4. Wiring the Digital Alarm Output Relay An alarm setpoint may be programmed from the front panel of the MGS-250. When the the sensed gas level exceeds the alarm setpoint, the MGS-250 enters the alarm state. An on-board relay is tied to the alarm state, so you may activate (or deactivate) external equipment based on the MGS-250’s current alarm status. Figure 11. Sample Relay Output Wiring NOTE: The relay can be programed to be failsafe (normally energized).
MGS-250 Manual 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 (see Figure 12), noting inverted B (-) and noninverted A (+) signal connectors per Table 8. Figure 12.
MGS-250 Manual IMPORTANT: Connect the RS-485 cable shield to pin 9 (board ground). NOTE: Selection of the Modbus Address and Baud Rate is completed through the gas detector setup menu, described later. No jumpers or hardware switch settings are required to configure the Modbus communications network. This is done electronically from the front panel display. NOTE: For Modbus communications with the MGS-250, the default communications parameters are as follows.
MGS-250 Manual Figure 13. Setting Network Termination Resistors 3.6. Conclusion Once the base is mounted and all wiring is complete, align the gas detector housing and press it onto the base. The gas detector will snap into position, completing 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.
MGS-250 Manual Section 4. Operation and Stabilization 4.1. Power Up and Warmup On powering up, the MGS-250 will sense for the presence of gas after an initial warm-up period of 2 to 5 minutes. The green LED will flash at a 1 second interval during the warm up. 4.2. Stabilization IMPORTANT: It is vital when first installing the gas detector that it warms up in an atmosphere that is known not to contain any background concentrations of refrigerant. Bacharach offers portable gas detectors for this purpose.
MGS-250 Manual 4.4. Alarms The following occurs during an alarm condition.
MGS-250 Manual Table 10: MGS-250 Behavior during a Non-Critical Fault Item Green LED Display Analog Output Modbus Registers Behavior During Non-Critical Fault State On (solid) Shows the appropriate fault code Operates normally Modbus registers indicate the fault. 4.5.3. Critical Faults Critical faults may indicate an unrecoverable condition. Please refer to Section 8 for more information. The following occurs when a critical fault condition exists.
MGS-250 Manual Section 5. Configure the Gas Detector 5.1. User Interface Overview The gas detector is configured through the built in menu system. Once mounting is complete, attach the gas detector to the base and apply power. Figure 14. The User Interface of the MGS-250 The user interface consists of four pushbuttons, a four digit LED numeric display, and a power LED. When the display is off, press any button to wake the display for 10 seconds. Buttons functions are listed in Table 12.
MGS-250 Manual 5.2. Setting Parameters 5.2.1. Overview Press and hold the information button () for 5 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 being the parameter value. Pressing Enter while a parameter is displayed allows the attributes of the parameter to be set. Each Parameter has its own attributes, as shown in the following table.
MGS-250 Manual Parameter Description Alarm ON Delays Sets the ON delay time (0-15 minutes) for the alarm output signals (relay, Modbus). The default delay is 0 minutes. Alarm OFF Delays Sets the OFF delay time for the alarm output signals (relay, Modbus) in minutes (0-15). The default delay is 0 minutes. Relay Contact Behavior (Failsafe Mode) Sets the default relay power state so that power loss can be detected.
MGS-250 Manual Parameter Description Display Mode The display can be turned on by using this parameter. When set to ON the display never shuts off (all operating modes). When ON the display shows the current gas concentration (or 0 if below the squelch). Note that P.-09 is disabled if P.-19=0. 00 OFF during normal operation when the ppm value is below the alarm setpoint (default) 01 ON In either case, the display will blink the measured PPM value during an alarm state.
MGS-250 Manual Parameter Description Buzzer Mute Time Sets a time (0-59 minutes) during which the active buzzer remains muted: • after the “I” button is pressed, or • after 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.).
MGS-250 Manual Parameter Description Analog Output Scaling Allows the user to select the full-scale PPM value that represents maximum analog output (e.g., 20 mA) for scaling the analog output. Adjustment range is from 100 PPM to 3500 PPM. Default = 3500 PPM. (The setting cannot be adjusted above 3500.) Use the Up and DOWN buttons to set the desired full scale value. All outputs will be scaled to the indicated full scale value. NOTE: Alarm values are not scaled, but are absolute values.
MGS-250 Manual Figure 15.
MGS-250 Manual Parameter Description Gas Test Mode Places the gas detector in gas test mode. 00 Disabled (default) 01 Enabled When enabled, the display continuously cycles through 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.
MGS-250 Manual Parameter Description Diagnostics Menu Parameter 18 provides access to the self diagnostic information. The LED display shows “DIAG” until the Enter button is pressed. Use the UP and DOWN buttons to scroll through the list of diagnostic attributes. A.-01 Current fault condition A.-02 Last fault A.-03 Days in service A.-04 Days since last adjust/test A.-05-A.-07 Factory Use Only A.-08 Detector temperature in °C A.-09 Temperature rate of change A.-10-A.
MGS-250 Manual Parameter Description Response Filtering This parameter is used to turn filtered output ON (01) or OFF (00). The default setting is ON (01). The Modbus and analog output are filtered so that responses below 75 ppm are squelched. If the display mode (P.-09) is set to ON (01) the display shows 0 for any signal level below 75 ppm. Some installations may wish to monitor the small analog output changes that may be created by the detector environment.
MGS-250 Manual Section 6. Functional Tests and Adjustments 6.1. Introduction To comply with the requirements of EN378 and the European F-GAS regulation, gas detectors must be tested annually. However, local regulations may specify the nature and frequency of this test. CAUTION: Check local regulations on calibration or testing requirements. CAUTION: The MGS-250 contains sensitive electronic components that can be easily damaged.
MGS-250 Manual IMPORTANT: After initial installation, the MGS-250 should be gas tested to ensure proper operation. IMPORTANT: The testing and/or adjustment of the unit must be carried out by a suitably qualified technician, and must be done: • • in accordance with this manual in compliance with locally applicable guidelines and regulations. Qualified operators of the unit should be aware of the regulations and standards set down by the industry/country for the testing or calibration of this unit.
MGS-250 Manual the actual gas detector response level (via parameter P.-17) to ensure that the gas detector activates at the specified gas concentration. Refer to the following sections for addition information on bump testing and gas detector response adjustment. CAUTION: Before you carry out the test or adjustment: • • • Advise occupants, plant operators, and supervisors.
MGS-250 Manual Step Bump Testing Using Calibration Gas Cylinders 1 Remove the Splash Shield accessory if one is used. 2 Connect the regulator to the test gas port using 3 mm or 1/8” inside diameter tubing (see below). 3 Expose the 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.
MGS-250 Manual NOTE: For improved accuracy and response, the gas detector should be protected from excess drafts while performing the adjustment. Excess air circulation may dilute the applied calibration gas and lead to lower than expected response. Step Adjustment Using Calibration Gas Cylinders 1 Connect the regulator to the test gas port using 3 mm or 1/8” inside diameter tubing. 2 Enable parameter P.-17 Gas Test Mode (see Section 5).
MGS-250 Manual Step Adjustment Using Calibration Gas Cylinders 7 If no further changes to the other parameters are required, press and hold the button for 5 seconds to exit the Parameter list. 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.
MGS-250 Manual Section 7. Modbus Communications 7.1. Introduction The MGS-250 gas detector can be configured to communicate on an RS-485 network using Modbus-RTU protocol. Before configuring the gas detector for Modbus communications, be sure your network connection is complete and your network termination switches are set appropriately. Refer to Chapter 3 (Wiring and Configuration) for details.
MGS-250 Manual 7.3. Analog Input Registers Analog input registers are read only and use function code 04. Table 14: Analog Input Registers Reg 50 Description Range Units P.
MGS-250 Manual 7.4. Analog Output Registers Analog output registers are readable (using function code 03) and writable (using function code 06). Table 15: Analog Output Registers Reg Description Range Units P.-## 75-3500 ppm P.-02 2000 Alarm setpoint 2001 Alarm ON delay (Alarm flag register 3000 is set to 1) 0-15 min P.-04 2002 Buzzer mute time 0-59 min P.-12 2003 Alarm OFF delay 0-15 min P.-05 2004 Relay action 0=NO 1=Failsafe none P.
MGS-250 Manual 7.5. Input Status Flags Input Status Flags are readable (using function code 02). Table 16: Input Status Flags Reg Description Range P.-## 3000 Alarm flag (0 or 1=Alarm) 0-1 -- 3001 Relay state (0 or 1=energized) 0-1 -- 3002 Detector fault (0 or 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) 3007 Reserved -- 3008 Reserved -- --- 0-1 -- 7.6.
MGS-250 Manual Section 8. Troubleshooting 8.1. Fault Codes To comply with the requirements of EN378 and the European F-GAS regulation, gas detectors must be tested annually. However, local regulations may specify the nature and frequency of this test. The MGS-250 features sophisticated internal status monitoring and will indicate whether a fault condition exists, both on the front display (F.-XX, with XX being the fault number) and over the Modbus communications network.
MGS-250 Manual Table 18: Fault Codes Description Fault Code Hex Code Possible Causes Gas Detector Temperature Fault 0x0001 Gas Detector temperature reports > 55° C or < -35° C. Gas Detector Temperature Rate of Change Fault 0x0002 Temperature rate of change exceeds ~1°C/min for more than 15 minutes. RS485 RX Fault 0x0004 Message too long for receive buffer. RS485 CRC Fault 0x0008 Transmission is corrupted (computed CRC doesn’t match transmitted CRC).
MGS-250 Manual Description Fault Code Hex Code Critical Faults : Possible Causes Critical fault. Cycle power to the sensor and see of the fault clears. If not, the gas detector should be removed from service and replaced. : 8.2. Diagnostics Attributes (P.-18) Use this option to review the built-in diagnostic attributes. Access the parameter list (see Section 5) and select P.-18. Press the Enter button to access the diagnostics, and then use the UP or DOWN button to select each attribute.
MGS-250 Manual Attribute : Description Reserved Displays the sensor temperature in °C. Displays the sensor’s approximate rate of temperature change per half minute interval (°C change over 30 seconds). : Reserved 8.3. Resetting MGS-250 to Default Values The gas detector may be reset to its default state, if needed, to aid in troubleshooting. All settings, including alarm setpoint, gas adjustments, selected gas curve, calibration data, Modbus address, etc.
MGS-250 Manual Step Description 1 Access diagnostics menu P.-18. 2 Press and hold both the UP and DOWN 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.
MGS-250 Manual Section 9. Replacement Parts and Accessories The following items are available as replacement parts. NOTE: All modules come ready to mount to the original mounting base provided. Table 21: Replacement Parts and Accessories Part Number Description 0051-2320 6400-0014 6400-0015 6400-0016 6400-0017 6400-0018 6400-0019 6400-0020 6400-0021 6400-0022 6400-0023 6400-0024 6400-0025 6400-0026 6400-0027 6400-0028 6400-0029 6490-9000 Calibration Gas Regulator, 1.
MGS-250 Manual DECLARATION OF CONFORMITY The manufacturer of the products covered by this declaration: Bacharach, Inc. 621 Hunt Valley Circle New Kensington, PA 15068 Year conformity is declared: 2013 Product(s): Refrigerant Gas Monitor/Transmitter Model(s): MGS-250 The undersigned hereby declares that the above referenced products are in conformity with the provisions of the following standard(s) and is in accordance with the following directive(s).
MGS-250 Manual Murco - A Bacharach Company 114a George’s Street LOWER Dun Laoghaire • Co Dublin • IRELAND Phone: +353 1 284 6388 • Fax: +353 1 284 6389 www.murcogasdetection.com • sales@murco.ie World Headquarters 621 Hunt Valley Circle, New Kensington, Pennsylvania 15068 Phone: 724-334-5000 • Toll Free: 1-800-736-4666 • Fax: 724-334-5001 Website: www.MyBacharach.com • E-mail: help@MyBacharach.
