937CU-AISTR-DC1 Installation Instructions Strain Gauge Converter
Bul. 937C Strain Gauge Converter Installation Instructions Symbols Used This symbol warns of possible danger. Failure to heed this warning may result in personal injury or death, or property damage, including destruction. Warning Warning This symbol warns the user of a possible fault. Failure to heed this warning can lead to total failure of the device and any other connected equipment. Attention This symbol draws attention to important information.
Bul. 937C Strain Gauge Converter Installation Instructions Safety Notes The Frequency Converter with Trip Values must only be operated by trained personnel in accordance with this handbook. Attention Warning Attention Attention The protection of operating personnel and of the system is only ensured if the devices are used in accordance with their intended purpose.
Bul. 937C Strain Gauge Converter Installation Instructions Overview The devices of the Bul. 937C IS Barriers, Isolators and Converters are used to transmit signals between field devices and the process control system or control. 937 products are suitable for connection to field devices in the hazardous area. The field current circuits of these devices are intrinsically safe and are galvanically isolated from the not intrinsically safe circuits.
Bul. 937C Strain Gauge Converter Installation Instructions Mounting and Connection The Strain Gauge Converter can be mounted on a 35 mm standard rail corresponding to DIN EN 60175. The devices must be snapped onto the rail vertically, and never slanted or tipped to the side. The Strain Gauge Converters are constructed in protection class IP20 and must therefore be protected from undesirable environmental conditions (water, small foreign objects). Attention CORRECT: Device snapped on vertically.
Bul. 937C Strain Gauge Converter Installation Instructions Connection The Bul. 937 series' slip-off terminals significantly simplify connection and construction of switching cabinets. They allow quick and error-free exchange of the unit when service is needed. The terminals can be screwed on, are self-opening, and have generous connection room for a wire diameter of up to 2.5 mm² and coded plugs, so that leads cannot be confused.
Bul. 937C Strain Gauge Converter Installation Instructions Terminals The remaining green terminals have the following functions: • • Terminals 7/8: current output Terminal 9: only for voltage output (see below.) • • • • • Terminals 10 ... 12: relay 1 Terminals 13/14: binary input 1 Terminals 15/14: binary input 2 Terminals 16 ... 18: relay 2 Terminals 19 ...
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Bul. 937C Strain Gauge Converter Installation Instructions Messages during operation • • Alarm freeze Hold on error Error messages • Err INT: error in the internal communication of the Strain Gauge Converters; may also occur if no sensor is connected • • • Err MEM: error in the memory of the Strain Gauge Converters Err SIM: Strain Gauge Converter in simulation mode (only when using FDT.
Bul. 937C Strain Gauge Converter Installation Instructions Parameterization mode control panel Programming Main menu parameterization mode Display mode OK + ESC (simultaneously, 1 sec) ESC Unit () Input () Output Service You can return to display mode from any point in the menu in parameterization mode by pressing the ESC key (possibly multiple times). If you do not press any key for 10 minutes in parameterization mode, the device automatically switches back into display mode.
Bul. 937C Strain Gauge Converter Installation Instructions Password You can protect the current configuration from unauthorized changes by using a password (See Service; inactive when Strain Gauge Converter is delivered). If password protection is active, the various settings in parameterization mode are visible before entry of the password, but may not be changed. The first time an attempt is made to change a setting, the device automatically displays a window for entering the password.
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Bul. 937C Strain Gauge Converter Installation Instructions Lowest menu level Choose Values, Enter Numbers At the lowest level of t. e menus, you can either choose between particular possible values for individual parameters, or enter a numeric value. Lowest menu level Parameters OK ESC current value, flashing , : ESC new value, flashing OK ESC new value, saved, not flashing When entering numeric values, please note: • If you press the or key, the value changes stepwise.
Bul. 937C Strain Gauge Converter Installation Instructions Unit The following figure shows the menu for the unit. The menu options of the lowest menu level are surrounded by a bold box. The unit is used for the measured value display (net and gross) and for all respective settings in the parameterisation mode. Unit —— kg* N % cbm (m³) pcs (pieces) * If more than 9999 kg are entered, the unit changes automatically from kg on t! The Strain Gauge Converter makes measurements in mV.
Bul. 937C Strain Gauge Converter Installation Instructions Sensor The following figures show the menus for the input parameters. The menu options of the lowest menu level are surrounded by a bold box. Menu options that are only displayed if you have selected certain parameter values elsewhere are highlighted in grey. Input —— Sensor —— Excitation —— 1V 2V 3V 4V Sensitivity —— 0.001 to 60.00 mV/V Cell rating —— 0.001 kg to 999.
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Bul. 937C Strain Gauge Converter Installation Instructions Excitation, Sensitivity, Cell rating • • • For the values of these parameters, please refer to the technical data of the sensor. The supply voltage exists between terminals 3 and 4. When connecting several measuring cells in parallel, the supply voltage and sensitivity must be transferred, the cell data are to be totalled. Only cells of the same design and with identical cell data may be connected in parallel.
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Bul. 937C Strain Gauge Converter Installation Instructions 18 • The settings influence the measuring cycle time: • By means of Smoothing, you influence the reaction of the Strain Gauge Converter to strongly fluctuating measured values. The Strain Gauge Converter processes the smoothed value instead of the current measured value. With an adjusted smoothing time of 0 sec, the input value is processed directly. The largest smoothing is reached with the attitude 10 sec.
Bul. 937C Strain Gauge Converter Installation Instructions Calibration The following figure shows the menu levels following the Calibration menu option. The menu options of the lowest menu level are surrounded by a bold box. Menu options that are only displayed if you have selected certain parameter values elsewhere are highlighted in grey. Calibration —— Zero —— Set —— -100 to +100 mV Execute —— yes no Adjust —— Weight —— 0.001 kg to 999.
Bul. 937C Strain Gauge Converter Installation Instructions Zero point For installations where a signal of 0 mV does not correspond to the measured value 0 in the selected unit, a zero offset can be stored. • If the zero offset is known from the data of the installation, please enter the value under Set displays. • If you select (after appropriate measures in the installation, e. g. removing all weights) Execute and then Yes, the current mV measured value is stored as zero point.
Bul. 937C Strain Gauge Converter Installation Instructions Notes on Zero point and Adjust • For the result of the adjust it does not matter whether you determine the zero point or the adjust value first. • Zero point and adjust value must be determined in the same unit (do not change the unit before both operations have been performed). • If you perform the adjust in a unit other than kg, a new adjust is required after changing the value kg/unit .
Bul. 937C Strain Gauge Converter Installation Instructions Range This parameter is required for evaluations in the unit %. • Under Set displays, enter the value that is to correspond to the gross value 100 % in the (before selecting %) selected unit kg, N, cbm or pcs (see section 7.2). Values between 0 and the maximum cell load are possible. • Alternatively, you can select Execute and then Yes after excitation of the cell (e. g. after applying a corresponding weight).
Bul. 937C Strain Gauge Converter Installation Instructions 7.5 Triggers The following figure shows the menus for trigger 1 and trigger 2. The menu options of the lowest menu level are surrounded by a bold box. For information on the binary inputs, see Connection section.
Bul. 937C Strain Gauge Converter Installation Instructions Relays The following figure shows the menus for the output parameters. Output —— Relay 1 —— Trip alarm Fault indication Relay 2 —— Trip alarm Fault indication Iout From the Relay 1 and Relay 2 menu options, you can use the OK key to get to a menu in which you can enter individual parameters for the selected relay. Both menus are structured in the same way and are thus only described once.
Bul. 937C Strain Gauge Converter Installation Instructions Trip alarm The following figures show the menu levels following the Trip alarm menu option. The menu options of the lowest menu level are surrounded by a bold box. If the Trip alarm function is activated (On), use the OK key to get from the Trip alarm menu option to the Min/Max menu option. If you reactivate the Trip alarm function, pressing the OK key twice takes you directly to the Min/Max menu option.
Bul. 937C Strain Gauge Converter Installation Instructions Delay —— 0 sec. to 250 sec. Alarm freeze —— On Off Hold on error —— On Off Operating behavior As the trip mode Max or Min are possible, as the operating mode Active or Passive are possible. Areas of application: • Trip mode Max, operating mode Active: alarm if the signal is above the trip value, e. g. horn on; protection against overfilling, e. g.
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Bul. 937C Strain Gauge Converter Installation Instructions • As the representation of the operating behavior in section 7.6.2 shows, the following must apply: − for the trip mode Max: trip point - hysteresis ≥ 0 − for the trip mode Min: trip point + hysteresis ≤upper limit of the trip point The limits are automatically determined by the Strain Gauge Converter being. • The hysteresis should be > 1 % of the trip point in order to prevent rapid switching of the relay.
Bul. 937C Strain Gauge Converter Installation Instructions Alarm freeze and Hold on error • • By means of the Alarm freeze you ensure that the operating personnel notices if the trip value is temporarily violated. If Alarm freeze On has been selected, the new condition is maintained after switching the relay, until the ESC key is pressed or the device is restarted. These actions reset the relay, unless the trip value is still exceeded.
Bul. 937C Strain Gauge Converter Installation Instructions Current output The following figures show the menu levels following the Iout menu option. The menu options of the lowest menu level are surrounded by a bold box. Iout —— Characteristic —— 20.20 -/+mA 4 - 20 NE 43 12.
Bul. 937C Strain Gauge Converter Installation Instructions Fault current —— Min Max Hold Up/down Inverted —— Normal Inverted Gross/Net, Span, Inverted • • • By means of the Gross/Net parameter, you determine whether the value for the Span is a gross value or a net value (gross value minus current tare). By means of the Span parameter, you determine the measured value range which is represented by the current output. − The span must be entered in the selected unit.
Bul. 937C Strain Gauge Converter Installation Instructions Characteristic The settings have the following meaning (for Inverted → normal) Selected setting 20.20 -/+mA mA + 20.5 + 20.0 0 Measured value - 20.0 - 20.5 - 1.25 % 0 100 % = span 101.25 % This setting converts the measured value 0 into -20 mA (i. e. into 20 mA in the case of changed polarity at the terminals 7 and 8), the span is converted into +20 mA (terminal 7 -, terminal 8 +), interim values are calculated proportionally.
Bul. 937C Strain Gauge Converter Installation Instructions This setting converts the measured value 0 into 4 mA, the span is converted into 20 mA, interim values are calculated proportionally. For values below the measured value 0, the output current decreases linearly to a minimum of 3.8 mA (-1.25 % of the measurement range). Further underflows cannot be evaluated (output 3.8 mA). If the span is exceeded, the output current increases linearly to a maximum of 20.5 mA (approx.
Bul. 937C Strain Gauge Converter Installation Instructions Selected setting 0 - 20 mA (b) mA 20.5 20.0 0 0 100 % = span 102.5 % Measured value This setting converts the measured value 0 into 0, the span (see section 7.7.1) is converted into 20 mA, interim values are calculated proportionally. Values below the measured value 0 cannot be evaluated (output 0 mA). If the span is exceeded, the output current increases linearly to a maximum of 20.5 mA (102.5 % of the measurement range).
Bul. 937C Strain Gauge Converter Installation Instructions Service The following figure shows the menus for the service parameters. The menu options of the lowest menu level are surrounded by a bold box. Service —— Password —— On Off Language —— Eng (English) De (German) RS 485 (see below) —— 0 to 31 Reset (see below.) —— yes no RS 485: Set the address of the Strain Gauge Converter for communication via the RS 485 interface here.
Bul. 937C Strain Gauge Converter Installation Instructions Factory settings Menu Main menu Input sensor Input adjustment Input Output relay 1 36 Parameter Unit Excitation voltage Sensitivity Cell rating Rate Cell error Smoothing Zero point Adjust Range Trigger 1 Trigger 2 Trip alarm MIN/Max (= Trip mode) Trip point Hysteresis Mode Net/Gross Delay Alarm freeze Hold on error Fault indication Factory setting kg 5V 2,000 mV/V 1000 kg Normal On 0 sec. 0.
Bul. 937C Strain Gauge Converter Installation Instructions Parameter Output relay 2 Parameter Trip alarm MIN/Max (= Trip mode) Trip point Hysteresis Mode Net/Gross Delay Alarm freeze Hold on error Fault indication Factory setting On (= selected) Max Output Iout Characteristic 20.20 -/+mA Service Net/Gross Span Fault current Inverted Password Net 20.00 kg Max Normal Off Language RS 485 Reset Eng 1 no Local setting 10.00 kg 10.00 kg Passive Net 0 sec.
Bul. 937C Strain Gauge Converter Installation Instructions RS 485 interface The Strain Gauge Converter can be connected to an RS 485 2-wire bus via the terminals 19 ... 21 or via the Power Rail. In principle, such a bus is structured as follows: +5V Strain Gauge Converter 21 390 Ω B line/+ 220 Ω 19 Connection cable 5 m max. 220 Ω Bus cable 500 m max. A line/- Connection cable 5 m max.
Bul. 937C Strain Gauge Converter Installation Instructions Requests via the RS 485 interface are not suitable for time-critical or safety-critical applications. Warning The Strain Gauge Converter can request the following information via the RS 485 interface e. g.
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Bul. 937C Strain Gauge Converter Installation Instructions Example The weight of a truck load is to be calculated. The empty weight of the truck can be between 7.5 t and 15 t, the load to be measured can be up to 20 t. To prevent an overloading of the truck an alarm is to be triggered at a weight above 20.5 t. The truck rests on 4 weighing cells which have been connected in parallel at the input of the Strain Gauge Converter.
Bul. 937C Strain Gauge Converter Installation Instructions Sensor data Because the truck scale rests on 4 measuring cells the parameters of each individual measuring cell must be combined: The following entries must be made in the menu Sensor: • Supply voltage: Here the resulting total resistance of the parallel connection of the 4 sensors must be taken into account.
Bul. 937C Strain Gauge Converter Installation Instructions Trigger inputs One trigger input must be parameterized as "Tare" to enable a subsequent zero point setup. Calibration The calibration can be carried out offline or online. Offline Calibration without mechanical load is the simplest way of calibrating the Strain Gauge Converter. However, inaccuracies are to be expected because the whole measuring chain is not included in the calibration process.
Bul. 937C Strain Gauge Converter Installation Instructions However, because the total mass to be measured is greater, the range must also be entered|. Under Input > Calibration > Range > Set the weight to be measured must be entered, in the example 35 t. With this setting the value 100 % will be displayed at 35 t if the unit is changed to %. The Strain Gauge Converter has now been calibrated including the whole measuring chain.
(DIR 10001176475) Publication 937-IN004A-EN-P - April 2014 (DIR 10001099008) Copyright © 2014 Rockwell Automation, Inc. All rights reserved. Printed in the U.S.A .