detcon inc. Detcon MicroSafe™ DM-634 Oxygen Deficiency Sensor (0-25% O2) Operator’s Installation & Instruction Manual June 18,2009 • Document #2016T • Version 6.
Table of Contents 3.0 Description 3.1 Principle of Operation 3.2 Application 3.3 Specifications 3.4 Operating Software 3.5 Installation 3.6 Start-up 3.7 Calibration 3.8 Status of Programming: Alarms, Calibration Level, RS-485 ID, and Sensor Life 3.9 Programming Alarms 3.10 Program Features 3.11 RS-485 Protocol 3.12 Display Contrast Adjust 3.12A Trouble Shooting Guide 3.13 Spare Parts List 3.14 Warranty 3.15 Service Policy 3.16 Software Flow Chart Detcon Model DM-634 Oxygen Sensor PG.
.0 DESCRIPTION Detcon MicroSafe™ Model DM-634, oxygen deficiency sensors are non-intrusive “Smart” sensors designed to detect and monitor O2 in air over the range of 0-25%. One of the primary features of the sensor is its method of automatic calibration which guides the user through each step via instructions displayed on the backlit LCD. The sensor features field adjustable, fully programmable alarms and provides relays for two alarms plus fault as standard.
3.0.2 Microprocessor Control Circuit The control circuit is microprocessor based and is packaged as a plug-in field replaceable module, facilitating easy replacement and minimum down time. Circuit functions include a basic sensor pre-amplifier, on-board power supplies, microprocessor, back lit alpha numeric display, alarm status LED indicators, magnetic programming switches, an RS-485 communication port, and a linear 4-20 mA DC output.
3.1 PRINCIPLE OF OPERATION Method of detection is by a controlled rate of diffusion. Air and gas diffuse through a sintered stainless steel filter and a diffusion barrier. As oxygen is adsorbed into the electrolyte solution a current is generated between the cathode and anode electrodes. This current output rises with increases in oxygen concentration and reverses with lower concentrations. The quick response of the cell results in continuous monitoring of ambient air conditions.
Power Consumption Normal operation = 28 mA (<3/4 watt); Full alarm = 85 mA (2 watts) Output 3 relays (alarm 1, alarm 2, and fault) contact rated 5 amps @ 250 VAC, 5 amps @ 30 VDC; Linear 4-20 mA DC; RS-485 Modbus™ Input Voltage 22.5-28 VDC 3.4 OPERATING SOFTWARE Operating software is menu listed with operator interface via the two magnetic program switches located under the face plate. The two switches are referred to as “PGM 1” and “PGM 2”.
* The estimated remaining sensor life. The menu item appears as: “SENSOR LIFE 100%” 3.4.3.2 Alarm 1 Level Adjustment The alarm 1 level is adjustable from 2.5% to 22.5%. The menu item appears as: “SET ALM1 @ 19.5%” 3.4.3.3 Alarm 2 Level Adjustment The alarm 2 level is adjustable from 2.5% to 22.5%. The menu item appears as: “SET ALM2 @ 17.5%” 3.4.3.4 Calibration Level Adjustment The calibration level is adjustable from 15.0% to 25.0% O2. The menu item appears as: “CalLevel @ xx.x%” 3.
Ventilation - Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a manner where the migration of gas clouds is quickly detected. Personnel Exposure - The undetected migration of gas clouds should not be allowed to approach concentrated personnel areas such as control rooms, maintenance or warehouse buildings.
energized/normally de-energized relay. The default settings of the alarms (jumpers removed) are normally deenergized relays, non-latching relays, and alarm points that activate during descending gas conditions. 4 3/4" 6 1/8" 5 1/2" 3/4" NPT 3/4" NPT 7 1/2" 1/4" Dia.
If a jumper tab is installed in the latch position, that alarm relay will be in the latching mode. The latching mode will latch the alarm after alarm conditions have cleared until the alarm reset function is activated. The non-latching mode (jumper removed) will allow alarms to de-activate automatically once alarm conditions have cleared. If a jumper tab is installed in the energize position, that alarm relay will be in the energized mode.
ID# SW1 SW2 none 0 0 1 0 1 2 0 2 3 0 3 4 0 4 5 0 5 6 0 6 7 0 7 8 0 8 9 0 9 10 0 A 11 0 B 12 0 C 13 0 D 14 0 E 15 0 F 16 1 0 17 1 1 18 1 2 19 1 3 20 1 4 21 1 5 22 1 6 23 1 7 24 1 8 25 1 9 26 1 A 27 1 B 28 1 C 29 1 D 30 1 E 31 1 F 32 2 0 33 2 1 34 2 2 35 2 3 36 2 4 37 2 5 38 2 6 39 2 7 40 2 8 41 2 9 42 2 A ID# SW1 SW2 43 2 B 44 2 C 45 2 D 46 2 E 47 2 F 48 3 0 49 3 1 50 3 2 51 3 3 52 3 4 53 3 5 54 3 6 55 3 7 56 3 8 57 3 9 58 3 A 59 3 B 60 3 C 61 3 D 62 3 E 63 3 F 64 4 0 65 4 1 66 4 2 67 4 3 68 4 4 69 4 5 70 4
Remote Transmitter DM-634-RT Remote Sensor DM-634-RS WHT BLU WHT BLK YEL BLU 1234 Figure #5A 3.6 START UP Upon completion of all mechanical mounting and termination of all field wiring, apply system power and observe the following normal conditions: a) “Fault” LED is off. b) A temporary upscale reading may occur as the sensor powers up. This upscale reading will clear to about 20.9% within a few minutes of turn-on, assuming there is no oxygen deficient condition in the area of the sensor.
Programming Magnet Operating Instructions Operator interface to MicroSafe™ gas detection products is via magnetic switches located behind the transmitter face plate. DO NOT remove the glass lens cover to calibrate or change programming parameters. Two switches labeled “PGM 1” and “PGM 2” allow for complete calibration and alarm level programming without removing the enclosure cover, thereby eliminating the need for area de-classification or the use of hot permits.
Figure #7 Program Switch #1 Plug-in Microprocessor Control Circuit CONTRAST PGM Display Contrast Adjust MODEL 1 detcon inc. HOUSTON, TEXAS DM-634 Menu Driven Display MicroSafe™ O2 Gas Sensor FLT ALM ALM 1 2 CAL PGM 2 Alarm & Cal LEDs Program Switch #2 d) From the programming menu scroll to the calibration level listing. The menu item appears as: “SET CAL LEVEL”.
3.7.4 Calibration Frequency In most applications, monthly to quarterly calibration intervals will assure reliable detection. However, industrial environments differ. Upon initial installation and commissioning, close frequency tests should be performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable calibration interval. 3.
“SET ALARM 1 LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1” for 3 seconds until the display reads “SET ALM1 @ 19.5%”, then withdraw the magnet. Use the programming magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the reading is equal to the desired alarm set point. Exit to the programming menu by holding the programming magnet over “PGM1” for 3 seconds, or automatically return to the programming menu in 30 seconds.
no parity, with the sensor set up as a slave device. A master controller up to 4000 feet away can theoretically poll up to 256 different sensors. This number may not be realistic in harsh environments where noise and/or wiring conditions would make it impractical to place so many devices on the same pair of wires. If a multi-point system is being utilized, each sensor should be set for a different address. Typical address settings are: 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11, etc.
Bit 3 Bit 2 Bit 1 Bit 0 1-Unit is in calibration 1-Alarm 2 is ascending 1-Alarm 2 is normally energized 1-Alarm 2 is latching 0-Normal operation 0-Alarm 2 is descending 0-Alarm 2 is normally de-energized 0-Alarm 2 is non-latching Low Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 1-Alarm 2 Relay is energized 1-Alarm 1 is ascending 1-Alarm 1 is normally energized 1-Alarm 1 is latching 1-Alarm 1 Relay is energized 1-Fault is normally energized 1-Fault is latching 1-Fault Relay is energized 0-Alarm
3.12 DISPLAY CONTRAST ADJUST Detcon MicroSafe™ sensors feature a 16 character backlit liquid crystal display. Like most LCD, character contrast can be affected by viewing angle and temperature. Temperature compensation circuitry included in the MicroSafe™ design will compensate for this characteristic, however temperature extremes may still cause a shift in the contrast. Display contrast can be adjusted by the user if necessary.
3.15 SERVICE POLICY Detcon, Inc., as manufacturer, warrants under intended normal use each new MicroSafe™ plug-in control circuit to be free from defects in material and workmanship for a period of two years from the date of shipment to the original purchaser. Detcon, Inc., further provides for a five year fixed fee service policy wherein any failed transmitter shall be repaired or replaced as is deemed necessary by Detcon, Inc., for a fixed fee of $65.00.
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