Instruction/ maintenance manual of the product TX91 Omega
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FM APPROVED TX91 Thermocouple T wo-Wire T emperature T ransmitter omega.com e-mail: info@omega.com For latest product manuals: omegamanual.info U ser ’ s Guide Shop online at MADE IN.
Servicing North America: U.S.A.: ISO 9001 Cer tified One Omega Drive, Box 4047 Stamford, CT 06907-0047 T el: (203) 359-1660 F AX: (203) 359-7700 e-mail: info@omega.com Canada: 976 Bergar Laval (Quebec) H7L 5A1, Canada T el: (514) 856-6928 F AX: (514) 856-6886 e-mail: info@omega.
It is the policy of OMEGA Engineering, Inc. to comply with all worldwide safety and EMC/EMI regulations that apply . OMEGA is co nstantly pur- suing certification of its products to the European New Approach Directives. OMEGA will add the CE mark to every appropriate de vice upon certification.
TX91 Miniature T wo-Wire Thermocouple T ransmitter Page Section 1 Introduction 1 1.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TX91 Miniature T wo-Wire Thermocouple T ransmitter Page Section 4 Calibration Instructions 18 4.1 Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 Set-up of Equipment . . . . . . . . . . . . . . . . . . .
1 1 Introduction 1.1 General Description The OMEGA ® TX90 Series T emperatur e T ransmitters consist of the TX91 Miniature T wo-W ire Thermocouple T ransmitter and the TX92 Miniature T wo-W ire R TD T ransmitter . This manual is written for the OMEGA TX91 Thermocouple T ransmitter .
Figure 1-1. Photo of TX90 Series T ransmitter Figure 1-2. General Dimensions (in inches) 1 2 Introduction 1 (For Mounting).
3 1 Introduction The TX91 transmitter is normally powered by an unr egulated DC power supply as shown in Figure 1-3. The pr oportionally-transmit- ted signal begins at 4 mA, at the low end of its temperature range, and increases to 20 mA, at the high end of its temperatur e range.
0 4 Introduction 1 The TX91 two-wire transmitter r eceives and measures signals from thermocouples and sends an output current of 4-20 mA which is directly proportional to the thermocouple millivolt input.
0 5 Introduction 1 The TX91 has reverse supply polarity pr otection and will operate with a wide range of supply voltages (1 1 to 44VDC). It has an input sensor break-pr otection circuit that forces the output curr ent to go upscale when the thermocouple wire opens.
Figure 1-4. S traight line Approximation of Curve 0 6 1 Introduction.
1.2 Features • 4-20 mA output • ±0.1% full-scale accuracy (with respect to the mV input signal) • Upscale break pr otection • Low cost 1.3 Models A vailable 1 Introduction 0 7 T able 1-1.
Model Number Description TX91-(*) Thermocouple transmitter (J, K, T , or E) NB1TX-(*) NB1 thermocouple probe, 12" L, 1 / 4 " O.D., ungrounded junction, 304SS sheath, TX91T ransmitter TX91 Models Available 8 *Insert range code from T able 1-1 For complete information on NB1 Thermocouple Probes, see the OMEGA T emperature Handbook.
9 2 Unpacking Remove the packing list and verify that all equipment has been received. If ther e are any questions about the shipment, please call the OMEGA Customer Service Department at 1-800-622-2378 or (203) 359-1660. Upon receipt of shipment, inspect the container and equipment for signs of damage.
3.1 Mounting the TX91 The TX91 T ransmitter may be: 1. surface mounted, 2. mounted inside a protection head (r efer to figure 3-1), or 3. installed into the OMEGA mounting track (part number RT) using an OMEGA mounting bracket (part number TX90-BR). Figure 3-2 shows the R T mounting track.
3 Installation Figure 3-1 Assembly of the TX91 T ransmitter Inside an OMEGA NB1 Protection Head (in inches) 11 DC PO WER SUPPL Y LO AD MOUNTING HOLES THERMOCOUPLE.
Figure 3-2 R T Mounting T rack (in inches) 12 Installation 3 CAUTION HANDTIGHTEN TRANSMITTER MOUNTING SCREWS ONL Y . DO NOT OVER- TIGHTEN..
3 Installation 13 Figure 3-3 TX90-BR Mounting Bracket (in inches).
Figure 3-4 Installation with Bracket and T rack (in inches) TX90-BR & R T 14 Installation 3 MOUNTING TRACK (RT) MOUNTING BRACKET TX90-BR.
15 3 Installation NOTE A milliamp monitoring instrument can be used in the circuit by connecting the monitor’ s positive lead to (+PS) and the negative lead to (M). This allows monitoring the current loop without disconnecting the main wiring. 3.2 Wiring the TX91 (Refer to Figure 3-5) 1.
Installation 3 Figure 3-5 W iring Diagram for the TX91 Potentiometers 16 THERMOCOUPLE.
17 4 Calibration Instructions 4.1 Equipment Required • Precision mV sour ce, with 0.001 mV resolution and ±0.002mV accuracy or • Precision DVM with ±0.
18 Calibration Instructions 4 4.2 Set-up of Equipment T o pr epare the ice bath: a) Fill a glass beaker with crushed ice made from distilled water . b) Fill the beaker with enough distilled water so that ice just becomes slush, but not enough to float the ice.
19 Calibration Instructions 4 4.3 Calibration Procedures (Refer to Figur e 4-1) Connect the calibration equipment according to Figur e 4-1 or 4-2. The thermocouple wire (J, K, T , E) must be of the same calibration as the transmitter being calibrated.
20 4 Calibration Instructions If a Thermocouple Calibrator/Simulator is used, such as the OMEGA Model CL51 1 Precision Calibrator , select the T emperature Input Z (zero) and S (span) values. 3. Set the DC mV source to the selected Z (zero) mV value. Adjust the Z potentiometer to read 4.
Figure 4-1. Calibration Set-Up Calibration Set-up 4 21.
Figure 4-2. Calibration Set-Up. (Alternate) 22 Calibration Instructions 4 SP AN TX91 ZERO INPUT THERMOCOUPLE WIRE.
4 Calibration Instructions 23 T able 4-1. Calibration Values for the TX92 T emperature mV INPUT Input Range Model REF 32°F Zero/Span TX92 Zero/Span 0/ 1 200°F -J2 -0.855/ 1 4.906 0/ 1 300°F -J3 -0.885/ 1 7.947 0/ 1 500°F -J4 -0.885/14.108 0/ 1 750°F -J5 -0.
Malfunction or incorrect operation may be caused by: 1. Reversed polarity: Check the wiring using Figure 3-5 as a guide. If the temperatur e of the thermocouple increases while the curr ent magnitude decreases, the pr oblem could caused by reversed polarity of the: a) thermocouple wiring b) power supply leads c) monitor instrument 2.
25 5 T roubleshooting Guide a) Measure the total r esistance of each device (excluding the transmitter and power supply) in the 20 mA loop, including the resistance of the lead wir es. b) Calculate the maximum allowable loop resistance using the formula: Loop Resistance (maximum) = V supply -1 1V 0.
26 6 Accessories Model No. Description TX90-BR Mounting Bracket PSU-24B Unregulated Power Supply , 24 V olts TX82A Process Loop-Powered Indicator RT 48” Mounting T rack.
27 7 Specifications General SIZE: 1.75" dia. X 1.125" high (includes terminal strip) ZERO/SP AN ADJUSTMENT RANGE: ±25% POWER SUPPL Y VOLT AGE OPERA TING RANGE: +11VDC to +44VDC, 28 mA max required per transmitter ACCURACY : ±0.
Specifications 7 28 THERMAL ZERO SHIFT : < 0.01%/°F of span (span >5 mV) < 0.02%/°F of span (2-5 mV span) THERMAL SP AN SHIFT : < 0.01%/°F of span WEIGHT : 1.5 oz (50g) Output CURRENT OUTPUT SP AN: 4-20 mA DC CURRENT OUTPUT LIMITS: 3 to 28 mA, typical MAXIMUM LOOP RESIST ANCE: (V supply – 11V)/0.
Appendix A Intrinsically Safe Interconnection Diagram 29.
WARRANTY / DISCLAIMER OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a period of 13 months from date of purchase. The OMEGA ® W ARRANTY adds an additional one (1) month grace period to the normal one (1) year product warranty to cover handling and shipping time.
Where Do I Find Everything I Need for Process Measurement and Control? O M EGA…Of Course! Shop online at omega.com TEMPERA TURE 䡺 ⻬ Thermocouple, RTD & Thermistor P r obes, Connectors, Panel.
An important point after buying a device Omega TX91 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Omega TX91 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Omega TX91 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Omega TX91 you will learn all the available features of the product, as well as information on its operation. The information that you get Omega TX91 will certainly help you make a decision on the purchase.
If you already are a holder of Omega TX91, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Omega TX91.
However, one of the most important roles played by the user manual is to help in solving problems with Omega TX91. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Omega TX91 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
