Process Alarm Module RTA 421

Transcription

1 Technical Information TI 074R/24/ae Process Alarm Module RTA 421 Alarm module and power supply for monitoring current or voltage signals Application Areas Plant and machine construction Panel builders Process monitoring Process control Features and Benefits 2 relays for set point monitoring (with SPDT contacts) Loop power supply for connected sensors LC display for alarm set points and bargraph Compact housing Front end set up using 3 push buttons The Power of Know How

2 Application The RTA 421 contactor monitors industrial processes for safe operation. The unit analyzes current (0/4 to 20 ma) and voltage (0/2 to 10 V) signals and switches two independent output relays if the values either exceed or undercut the preset alarm set points. Possible applications include pump control in the waste water industry, and level measurement in silos and tanks. Display and operating elements 4-digit LCD with alarm markings and bargraph LED s - Operation display - Fault display - Condition display set point relays Enter Push Button Selection keys Both set points are simultaneously visible in the easy to read display. The ten segment bargraph additionally displays the percentage value of the connected signal. The actual percentage measured value in the measurement circuit can be displayed by operating either the + or - push button. A quick set up can be started by operating the + and E push buttons. This feature is especially useful if the set points are to be frequently changed. SP 1 and SP 2 can be changed easily, even during operation, without opening the main set up menu. If required, a 2 digit security code is available in order to stop any unauthorized changes from being made to the alarm set points. Application Example Signal input with loop power supply Pump Relay 1 Relay 2

3 Application Example Example - alarm set point monitor The level in a 10 foot high silo is to be displayed front end and also monitored for a minimum level of 2 feet (20%) and a maximum level of 8 feet (80%). The hysteresis, in order to avoid unnecessary relay switching in the area of the set points, is 2% in both cases. The minimum level must also be set with a 10 second time delay. Set up: Input signal and display: - Sensor signal 4 to 20 ma equals 0 to 10 feet Set point 1: - Minimum monitoring - Switch threshold 20% (2 ft.) - Hysteresis 2% - Time delay 10 seconds Set point 2: - Maximum monitoring - Switch threshold 80% (8 ft.) - Hysteresis 2% - Time delay 0 seconds SP 2 SP 1 Example - deep well measurement The water depth in % (with the water surface well full as the base) is to be measured and displayed. Set up: Well full: - Sensor signal 20 ma - Numeric display is to be 0% (when operating + or -) Well empty: - Sensor signal 4 ma - Numeric display is to be 100% (when operating + or -) Well full Well empty 0% (20 ma) 100% (4 ma) 1.77" 4.41" Housing (45) (112) ENDRESS+HAUSER RTA " (96) 4.25" (108)

4 Terminal Layout and Electrical Connection Relay Relays (internal circuit) Relay Relay 1 Relay L/L+ N/L- Contact condition shown in alarm or power out Current input Current input with loop power supply Voltage input 0/4 to 20 ma 4 to 20 ma 0/2 to 10 VDC + - Y I Analog input with loop power supply L/L+ N/L Terminal layout In and outputs L / L+ N / L- 81 L for AC, L+ for DC N for AC, L- for DC + 24 V loop power connection 11 Ground Current, voltage loop power connection 15 Measuring signal Voltage 0/2 to 10 V 16 Measuring signal Current 0/4 to 20 ma 41 Normally closed contact 42 Common 43 Normally open contact 51 Normally closed contact 52 Common 53 Normally open contact Loop power supply (option) Input measurement signal Relay output 1 Relay output 2 Technical Data General information Input Manufacturer Endress+Hauser Description RTA 421 Unit function Alarm set point switch with loop power supply. Used for monitoring either current or voltage signals Alarm module The unit monitors the input signal and checks if it is within the preset alarm setpoints. The two built-in relays switch if the signal wanders either above or below the preset alarm set point values. A built-in loop power supply can be used to power connected sensors. Measurement principle The analog signal connected to the input is digitized, analyzed, and displayed. When the preset alarm set point is reached, one of the relays is independently switched. Measurement system Micro controlled measurement system with LCD, analog input, alarm set points, and loop power circuit. Number of inputs 1 Type Current and voltage Measurement range Current, 0/4 to 20 ma, maximum current 150 ma, R i = 5 Ω Voltage, 0/2 to 10 V, maximum voltage 50 V, R i = 1 MΩ Resolution Current, 83 µa, 8 Bit Voltage, 41 mv, 8 Bit Over range 10% Integration time 4/second

5 Output (loop power supply) Output (relays) Output signal 24 V ± 20%, 30 ma Number of outputs 1 Galvanic isolation Between power supply and relay outputs Signal Binary, switches when alarm set point is reached Number of relay outputs 2 Contact type SPDT potential free contact per relay Contact load <= 250 VAC, 8(2) A / 30 VDC, 5(2) A Accuracy Application conditions Voltage Current Installation conditions Installation angle 0.5% FSD Temperature drift, 0.02% / K ambient temperature 0.5% FSD Temperature drift, 0.02% / K ambient temperature No limit Ambient conditions Ambient temperature 0 to +160 F (-20 to +70 C) Storage temperature 0 to +160 F (-20 to +70 C) Climatic classification To EN Class B3 Ingress protection IP 20 EMC / immunity Norm To EN 61326, Class A (industrial conditions) Safety Norm To EN ; overvoltage category II; installation area excessive current system 10 A Mechanical construction Display and operating system Alarm set point function Construction Housing for top hat DIN rail mounting to EN Dimensions H 4.25 (108 mm) W 1.77 (45 mm) D 4.41 (112 mm) Weight < 1 lb (approximately 0.15 kg) Materials Housing, plastic PC/ABS, UL 94V0 Electrical connection Keyed, plug on screw terminals, 14 AWG (2.5 mm 2 ) cable size Display LED: operation, 1 green; fault condition, 1 red; alarm set point, 2 yellow LC display: numeric, 4 x 7 segment; alarm set point condition, 2 x channel number, 4 x 1 segment; bargraph; 10 segment Display range 2 x 0 to 99% Operation 3 push button operation (- / + / E) Mode Minimum, maximum Switch threshold 00 to 99% Hysteresis 00 to 99% Time delay 00 to 99 seconds Reaction time 0.4 seconds 98 to 126 VAC, 50/60 Hz 196 to 253 VAC, 50/60 Hz 21 to 28 VDC Power consumption Maximum 3 VA Fuse 315 ma slow blow Input current limit I max / In < 15 Certificates CE mark By attaching the CE mark, Endress+Hauser confirms that the instrument fulfills all the requirements of the relevant EC directives (89/336/EWG and 73/23/EWG)

6 Ordering Information RTA 421 alarm module RTA Certification A Non-hazardous area version to 253 VAC, 50/60 Hz 2 98 to 126 VAC, 50/60 Hz (e.g. 115 VAC, 60 Hz) 3 21 to 28 VDC 3 Loop power supply 1 Loop power supply not required 2 With loop power supply 4 Model A Standard Supplemental Documentation Operating instructions BA 101R/09/en Accessories NEMA 4X field mounting protective housing Part No