Summary of Contents for H2O Rx DCH-2
- Page 1 CONDUCTIVITY- TEMPERATURE CONTROLLER DCH-2 USERS GUIDE DCH-2 Instruction manual PAGE 1...
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Page 2: Table Of Contents
OPERATION ......11 Initial check of the DCH-2 ....11 The LCD display . -
Page 3: Specifications
240VAC/Amps. (non inductive) Set point adjustment fully independent over entire selected range. Cell: 3/4" BSP thread inline type with moulded 4 pin socket for cable connection. (Immersion type available as optional extra.) Cell material: Polypropylene & stainless steel. DCH-2 Instruction manual PAGE 3... -
Page 4: Specifications (Cont.)
C, 12mA = 50 C, 20mA = 100 Sensor: NTC Thermistor type (rated temperature range 0-250 Size: 6mm Dia. x 120mm length. Sensor body: 316 stainless steel with moulded 3 metres cable. FIG.1 THE LCM-2 CONTROLLER PAGE 4 DCH-2 Instruction manual... -
Page 5: Introduction
INTRODUCTION The DCH-2 is well suited to operate in the hot and damp conditions often present around boilers, cooling towers and industrial sites in general. Moisture and accidental sprays are sealed off from the sensitive parts of the instrument with the transparent lid securely held in place with the 4 fasteners supplied with the unit. - Page 6 The legend for the terminals printed on the subpanel allows an easy identification of the appropriate connections. The DCH-2 can monitor and/or control conductivity and temperature simultaneously in an installation with the proper selection of the SET POINT configuration. The inherent accuracy of the 4-20mA constant...
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Page 7: Installation
INSTALLATION Instrument Installation and setting up of the DCH-2 is easy and straight forward. No special tools are required. (See Fig.2) The 4 screws are inserted through 4 corner holes (locking holes for the transparent lid) and also fastened through them with a screw driver. All cables are fed through the 3 cable glands and terminated at the appropriate terminals. -
Page 8: 4-20Ma Constant Current Output
C = 4mA, C = 12mA, C = 20mA The DCH-2 now features a fully isolated 4-20mA output and can be directly connected to other devices or micro processors without affect- ing the performance of the DCH-2. The 4-20mA output is DC current. The signal wires therefore must be connected with the right polarity observed. -
Page 9: Panel Mounting
(See Fig.4) Slide the instrument over the slot opening at the back, check that the unit hangs level and secure it with two screws inserted through the slots at the two bottom corners. FIG.4 ESCUTCHEON FOR THE DCH-2 DCH-2 Instruction manual PAGE 9... - Page 10 PAGE 10 DCH-2 Instruction manual...
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Page 11: Operation
OPERATION Initial check of the DCH-2 The LCD display, selected range light and a combination (depend-ent on the instrument configuration) of the small LED’s will light up once the instrument is properly installed and the power connected. The two output relays may latch depending on the position of the SET POINT controls. -
Page 12: The Lcd Display
Resolution of this range is 10uS (TABLE 3) 100-199,999uS The displayed reading is multiplied by 1000 to get the correct measured value. Resolution of this range is 100uS. (TABLE 4) FIG.6 THE DIFFERENT RANGE SETTINGS OF THE DCH-2 PAGE 12 DCH-2 Instruction manual... -
Page 13: Selecting Mode Of Operation
SW5 selects temperature or conductivity tracking of the 4-20mA current out-put. The combinations of operation with these settings are to numerous for all to be mentioned here. Fig.7 gives some examples for various configurations. FIG.7 CONFIGURATION OF THE CONTROLS DCH-2 Instruction manual PAGE 13... - Page 14 FIG.8 USED IN CHEMICAL ADDITION FIG.9 AUTOMATIC BOILER TDS BLOWDOWN PAGE 14 DCH-2 Instruction manual...
- Page 15 FIG.10 AUTOMATIC COOLING TOWER BLEED FIG.11 USED WITH A RINSE TANK DCH-2 Instruction manual PAGE 15...
- Page 16 FIG.12 CRH-41 RECORDING TEMPERATURE PAGE 16 DCH-2 Instruction manual...
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Page 17: Calibration Of The Dch-2
CALIBRATION OF THE DCH-2 Calibrating conductivity For best performance use buffers nearest the uS range actually used in the installation. To adjust the calibration place the electrode in a known buffer solution. Always check the temperature measurement before any conductivity adjustments are done as the electrode is temperature dependent. -
Page 18: Calibrating Temperature With The Electrode
The standard polypropylene electrode takes aprox. 15 min to track temperature changes of 50 C. If the installation requires an accurate and fast tracking of temperature or conductivity the stainless steel temperature sensor TS-316 must be used in place of the build-in temp. sensor. PAGE 18 DCH-2 Instruction manual... -
Page 19: Temperature Compensation For Conductivity
A conductivity controller has to compensate for this by reducing the sensitivity of the instrument to maintain an overall accuracy of measurement. The DCH-2 has a com- pensation factor set at 0.2 that means the conductivity gain reduces by a factor of 5 with a temperature increase of 100 C. -
Page 20: Setting Compensation Factor
The temperature reading displays an over-range mode (showing a 1 and three blank digits) if the sensor is faulty or a connection to the DCH-2 becomes open circuit. PAGE 20 DCH-2 Instruction manual... -
Page 21: Dch-2 And High/Low Temperature Alarm
DCH-2 controlling uS with high/low temperature alarm This example illustrated below is only one of many combinations possible with the DCH-2 controller. DCH-2 CONTROLLER 4-20ma OUTPUT SET INTER- NALLY FOR TEMPERATURE TRACKING. CSR-2 4-20mA signal ALARM BELL ACTIVATED BY TOO HIGH OR... -
Page 22: Options
The CRH-31/41 chart recorder can be used to record conductivity or temperature. The CSR-2 current sense relay controller expands the DCH-2 to a four set point controller with the ability to select a combination of conductivity and temperature controls. -
Page 23: Warranty
Any parts in the instrument have been changed or have been altered in any way. ° The serial number is removed or defaced. All other warranties and conditions, express or implied, are void. MODEL: DCH-2 SERIAL NO: SOLD & SERVICED: DCH-2 Instruction manual PAGE 23... - Page 24 NOTES: PAGE 24 DCH-2 Instruction manual...
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