AR EA kajdfkjl; lkjdflkjal; ldkfj;alk alskjdf ;lsdkf 7079 ph/orp Transmitter 70-82-03-08 1/97 Page 1 of 5 Specification Overview The 7079 ph/orp Transmitter is designed for chemical process industry applications where an inexpensive, versatile two-wire transmitter is needed. The Transmitter produces a 4-20 ma standard output signal proportional to a ph or ORP input, with explosion-proof features and intrinsically safe operation. The 7079 Transmitter is compatible with most ph and ORP electrode assemblies currently available, and may be retrofitted to existing twowire systems. It can be supplied with a low-impedance glass electrode preamplifier mounted in its case or without the preamplifier, for use with electrode assemblies having an integral two-wire type preamplifier. Features/Benefits True 2-wire (or 4-wire), transmitter system, to reduce wiring and installation costs. Isolated 4-20 ma output, proportional to ph or ORP oxidation reduction potential. Switch-selectable ranges: any 2, 4, 6, 8, 10, 12 or 14 ph span over the range of 0-14 ph; ORP over any 400, 600, 800, 1000, 1200 or 1400 mv span. External zero and slope adjustment. FM approved Intrinsically Safe for Class I, Division 1, Group A, B, C and D locations. FM Approved Explosion Proof Class I, Division 1, Group C and D locations. Compatible with glass or DURAFET ph electrodes. 7.08 ph Figure 1 7079 ph/orp Transmitter in NEMA 4X Plastic Case WH EN IGH T T POWER C LO SED IS C ONN ECT ED KEEP 6.91 ph H AZARD OU S WARN ING Figure 2 7079 ph/orp Transmitter in NEMA 4 Metal Case Noryl corrosion-resistant plastic case, NEMA 4X, IP65 design, suitable for outdoor mounting; or Cast-aluminum case, NEMA 4, IP65 waterproof/explosionproof with corrosion-resistant urethane-polyester finish. - IN Transient and surge-current protection (lightning protection) standard. Plug-in printed circuit board for easy servicing. Industrial Automation and Control, 16404 N. Black Canyon Highway, Phoenix, AZ 85023 Printed in U.S.A.. Copyright 1996 Honeywell Inc.
Page 2 The Transmitter receives its 24 V dc supply from the measuring or controlling instrument (such as a Honeywell UDC controller), or a separately-ordered power supply. The Transmitter provides a 4-20 ma output signal, compatible with most process control systems, can be used to represent ph level and ORP ranges. For ph measurements, the Transmitter range can be 0-14 ph, or any switch-selectable 2, 4, 6, 8, 10, or 12 ph span within the range of 0-14 ph; an external adjustment permits suppressing zero as required (e.g., a 4 ph span could be selected for Transmitter Operation working range of 6-10 ph). For ORP measurements, calibration permits a choice of any 400, 600, 800, 1000, 1200 or 1400 mv span, to a maximum of 1400 mv; the external adjustment permits zero elevation (e.g., -500 to +500 or 400 to 1000 mv) as desired, which can easily be read on the digital display. The Transmitter can be housed in a corrosion-resistant NEMA 4X plastic case (with internal conductive coating for effective EMI/RFI shielding) or in a NEMA 4 heavy-duty cast-aluminum waterproof case with a urethanepolyester finish. See "Case Classifications" listed in Specifications. Optional Features LCD Display Ranges also can be displayed on the optional 3½ digit, seven segment liquid crystal display mounted in the case. Alarm /Control Module To provide simple but effective on-off control, a separately-ordered 7078 Alarm/Control Module, with as many as four plug-in high and/or low alarm/control relays, may be connected into the output circuit of the Transmitter. Specifications Table 1 7079 ph/orp Transmitter Operating Conditions Parameter Reference Condition Operative Limits ºC ºF ºC ºF Ambient Temperature 25 ± 1 77± 1.8-10 to +60 14 to 140 Relative Humidity, RH% 10 to 40 10 to 95 Line voltage 24 Vdc 19-34 V dc Operating Influences Temperature: 0.002 ph/ºc (0.001 ph/ºf) or 0.2 mv/ºc (0.11 mv/ºf) Humidity: Negligible Power Requirements Maximum Load Resistance Standard: 24 V dc supply, 2-wire (500 ohm max. load). (The 7079 drops 14 V regardless of load or power supply.) Supply Voltage Maximum Load 19 V dc 24 V dc 29 V dc 34 V dc 250 ohms 500 ohms 750 ohms 1000 ohms
Page 3 Specifications (continued) Table 2 Performance Under Reference Conditions Range Parameter Description With the digital display option, the transmitter will monitor and display in realtime ph value over the full 0-14 ph range. ORP values are displayed over the full 0-1400 mv range when set up as a Redox transmitter. Whether blind or with optional LCD, the 4-20 ma isolated current output is fully selectable to represent any 2, 4, 6, 8, 10, 12 or 14 ph span, over the range of 0-14 ph; or any 400, 600, 800, 1000, 1200, or 1400 mv span, to a maximum of 1400 mv. Field span selection for ph is accomplished by internally set switches mounted on the main circuit board. Note: The LCD readout is not compatible with an antimony electrode due to the large zero offset of the electrode. Range Adjustment Output Accuracy: Drift External zero and slope adjustments are provided on the case. - For ph measurements, zero can be evaluated or suppressed as required. - For ORP Measurements, zero can be evaluated or suppressed as required. - The slope adjustment permits matching the Transmitter precisely to the electrode output. 4-20 ma dc into 0 to 500 ohms, operating on 24 V dc two-wire supply. See maximum load resistance spec under "Power Requirements". ± 0.02 ph or ± 1.2 mv For ph, less than 0.01 ph/week For ORP, less than 1.0 mv/week Repeatability: Zero-based Linearity Preamplifier Optional LCD Readout 0.01 ph or 1 mv 0.1% of span For input signals directly from electrodes, the transmitter is supplied with a preamplifier (mounted within the case) having 10 12 ohms input impedance. If an internal preamp is not selected, input signals come from a remote preamp. A remote preamp must always be used with DURAFET electrodes. Electrode temperature compensation is provided in all preamplifiers. Integrally mounted in case. Highly visible liquid-crystal display, 3 ½digit, with ½" numerals. Resolution 0.01 ph of 1 mv.
Page 4 Specifications (continued) Table 3 Physical Parameter Case Classifications: Metal- Description Explosion-Proof - FM approved explosion-proof for Class I, Division 1, Groups C and D (120 V and 24 V). Must use potting "Y s". Plastic or Metal- Intrinsically Safe - FM approved Class I, Division 1, Groups A, B, C and D 24 V version ONLY. Must use approved barriers and be wired in accordance with Honeywell drawing C-ID-081609-5 or C-ID-081609-6. Case Terminations: Plastic - Two ¾" NPT conduit connections and one ¾" unthreaded hole in plastic case bottom to allow for electrode cable entry into case. Metal - Choice of three ½" NPT conduit connections for power supply and output leads, one ¾" NPT conduit connection at metal case bottom for electrode cable entry. Case Mounting: Plastic - Rugged metal bracket is supplied loose. Metal - Rugged metal bracket is supplied mounted as part of 7079 case. Case Dimensions: (Diameter x Length) Plastic- No LCD, 5¼" x 7¾" (133 x 197 mm), 24 V or 120 V With LCD, 5¼" x 9½" (133 x 241 mm), 24 V or 120 V. Metal - No LCD, 4¾" x 6½" (120 x 165 mm), 24 V. With LCD, 4¾" x 9" (120 x 228 mm), 24 V. No LCD, 4¾" x 8" (120 x 208 mm), 120 V. With LCD, 4¾" x 10½" (120 x 267 mm), 120 V. Case weight: Plastic - 4½ lbs (2 kg) Metal - 16 lbs (7.3kg). 5.250 (133.35) 5.250 (133.35) 3/4" NPT (2 places) for Electrical Connections Mounting bracket for Pipe or wall mounting Note 1 Mounting Bracket 1.125 (28.58) Dia. Hole for Customer s connections (3/4 NPT conduit HUB available L&N Part No. 008555) 1/2 x 12-14 thread forming screws (4) 1/4 KLLW 1/4-20 Nut 1/2 x 1/4-20 HXCAPSS 6.531 (165.89) 7.531 (191.29) 3.468 (88.09) Note 2 5/16-18 "U" bolts (2) and hardware Transmitter Dimensions
Access Cover to Transmitter Circuitry Optional Meter Housing 10.500 (266.70) Z S 8.000 (203.20) 9.000 (228.60) 6.500 (165.10).875 (22.23) 1.375 (34.93) Allow.875 (22.23) for Removal of Covers (Typical) Access Cover to Terminal Board Optional Power Supply Housing 4.687 (119.05) 1.406 (35.71) 3/4 NPT for Customer s Connections.406 W X.531 LG (10.31) (13.49) Slots (4) 1.406 (35.71) 2.812 (71.42) 2.812 (71.42) Cast Aluminum Case Distributor : Industrial Automation and Control Honeywell Inc. In the U.S.A.: Honeywell Industrial Automation and Control, 16404 North Black Canyon HWY., Phoenix, AZ 85023, (800) 343-0228 In Europe: Honeywell S.A., 80084 Amiens Cedex 2, (33) 22.54.56.56 Honeywell Control System Ltd., Honeywell House, Bracknell, UK-RG 12 1 EB, (44) 1344 826000 In Japan: Yamatake-Honeywell Co. Ltd., Nagai Int l Bldg., 2-12 - 19 Shibuya-Ku, Tokyo 150 Japan, 81-3-3486-2051 In Asia: Honeywell Asia Pacific Inc., Room 3213-3225, Sun Hung kai Centre, No. 30 Harbor Road, Wanchai, Hong Kong, (852) 829-8298 In the Mediterranean: Africa and Middle East Region, Honeywell SpA, Via Vittor Pisani 13, 20124 Milano, Italy (39-2) 67731 Honeywell Pacific Division: Honeywell Pty Ltd., 5 Thomas Holt Drive, North Ryde Sydney, NSW Australia 2113, (61-2) 353 7000 In Canada: The Honeywell Centre, 155 Gordon Baker Road, Ontario M2H 3N7, 1-800-461-0013 In Latin America: Honeywell Inc.,14505 Commerce Way, Suite 500, Miami Lakes, Florida 33016-1556, (305) 364-2300