3741DC - Measurement Daytronic - Free user manual and instructions

USER MANUAL 3741DC Daytronic

Death, serious injury, or fire hazard could result from improper connection of this instrument. Read and understand this manual before connecting this instrument. Follow all installation and operating instructions while using this instrument.

Connection of this instrument must be performed in compliance with the National Electrical Code (ANSI/NFPA 70-2014) of USA and any additional safety requirements applicable to your installation.

Installation, operation, and maintenance of this instrument must be performed by qualified personnel only. The National Electrical Code defines a qualified person as “one who has demonstrated the skills and knowledge related to the construction and operation of the electrical equipment and installations, and who has received safety training on the hazards involved.”

Qualified personnel who work on or near exposed energized electrical conductors must follow applicable safety related work practices and procedures including appropriate personal protective equipment in compliance with the Standard for Electrical Safety Requirements for Employee Workplaces (ANSI/NFPA 70E-2012) of USA and any additional workplace safety requirements applicable to your installation.

ADVERTENCIA

The following safety precautions must be followed whenever any type of voltage or current connection is being made to the instrument.

Before connecting to electric circuits or pulse initiating equipment, open their related breakers or disconnects. It is recommended NOT TO install any connection of the instrument on live power lines. Only Qualified Service personnel that have demonstrated the abilities and received the proper safety training are capable of connecting to live circuits.
- Connections must be made to the instrument first, then connect to the circuit to be monitored.
- Wear proper personal protective equipment, including safety glasses and insulated gloves when making connections to power circuits.
- Hands, shoes and floor must be dry when making any connection to a power line.
Before each use, inspect all cables for breaks or cracks in the insulation. Replace immediately if defective.
If the equipment is used in a manner not specified in this user's guide, the protection provided by the equipment may be impaired.

Standard Accessories

Standard accessories
The following table lists the 3700 standard accessories.

3741 Manual	92381.00
3741 Quick Reference Guide	92380.00
5 Pin connector, analog signals	25657-LF
8 Pin connector, transducer	25658-LF
10 Pin connector, logic	25606.00
*US Power Cord	USSTDCORD (900744)
*European Power Cord	EUROSTDCORD (115369-G1)
*United Kingdom Power Cord	UKSTDCORD (115368-G2)
*Australian Power Cord	AUSTDCORD (901347)
Desk top feet (4ea.)	35058.00
*User specified, one standard only.

1 GENERAL DESCRIPTION AND SPECIFICATIONS

The Model 3741 is a single-channel panel instrument used to display and produce an analog output that represents Horsepower. The unit receives its inputs from the frequency source which is also connected to the Speed conditioner (typically the 3740 meter) and the amplified analog signal from the Torque conditioner (typically the 3770 or 3778 meter) for the Horsepower measurement. The 3741 unit is based on the 3740 conditioning and specifications. Proper Horsepower calculation and readout are provided using the Wide Range Span controls to maximize the analog output signal and the Display controls for proper engineering readout of the torque / speed equation.

The Model 3741 is calibrated by using the “two-point” process involving known zero & span standards. The first step is to calibrate the speed and the torque conditioners independently and then utilizing the "RCAL" feature - when using the 3740 and 3770/8 meters or using known input standards which in turn will be used to calibrate the 3741 for proper Horsepower engineering units.

FRONT PANEL VIEW OF 3741 CONTROLS (Front Display Cover Removed)

1. X. X. X. X 0 -1 9 9 9 5 0 FINE ADJUST ZERO SPAN F C F 5000 1 2 3 4 5 6 7 10000 20000 RANGE SPAN 1 2 3 4 5 6 7 WIDE ADJUST ANALOG CTRL UP Function Down 5 1 - VDC OUT 10 8 Hz 2 - not used 8 Hz 3 - FILTER 32 Hz 8 Hz 4 - FILTER 2 Hz 05-2.0 5 - SEN A 25-10 05-2.0 6 - SEN B 1.0-40 05-2.0 7 - SEN C 5.0-250 DISPLAY SPAN C F OFF RCAL FINE ADJUST FINE ZERO COARSE SPAN FINE SPAN WIDE ADJUST RANGE - WIDE ADJUST SPAN - WIDE ADJUST DISPLAY SPAN COARSE FINE REMOTE CALIBRATION ANALOG CONTROL SETTINGS 1 - VOLTAGE OUTPUT - 5.0 or 10.0 VDC 2 - Not Used 3 - ANALOG FILTER 4 - ANALOG FILTER 5 - SENSITIVITY A 6 - SENSITIVITY B 7 - SENSITIVITY C DISPLAY CONFIGURATION Sw 1,2,3,4 DECIMAL POINT PLACEMENT Sw 5 DUMMY ZERO Sw 6 & 7 DISPLAY RESOLUTION

3741 SPECIFICATIONS

Selected Measurement Ranges: Adjustable 250 Hz to 128 kHz; nominal full-scale for RPM input

Input Types: An AC or Unipolar pulse signal, grounded or floating and ±5 or 10 Vdc Torque Signal Input

Excitation: ±12 VDC @ 50 mA; + 12 V only @ 100mA

Power Supply: Voltage 90 - 250 VAC, 47 -63 Hz; Optional 9-36 VDC (Model 3741DC) Consumption 10 Watts

Physical Parameters: 5.68" W x 2.84" H x 7.06" D; weight - 3.25 Lbs.

Analog Output: selectable; ±5, ±10 VDC, 4 -20 mA or 4 -12 -20 mA (20 % over -range on voltage outputs only)

Operating Temperature: 0 to +55 Degrees C, 5 to 95% relative humidity, non-condensing

Altitude: 2000m (6560 ft) maximum

Installation Category: Installation Category II, Pollution Degree 2

Amplifier:

Normal-Mode Range: 250 Vrms operating; 290 V without instrument damage

Common - Mode Range: ± 125 V

Input Impedance: Greater than 200 kOhms on all ranges

Offset: vs. Temperature: ±30 ppm/°C; vs. Time: ±10 ppm/month

Gain Accuracy: ± 0.02% full scale, typical, limited only by calibration accuracy

Gain Stability: vs. Temperature: ±30 ppm/°C; vs. Time: ±10 ppm/month

Linearity: better than ± 0.03% of full scale

Filter: 9-pole modified Butterworth; 3 dB down at 2 Hz, 8 Hz or 32 Hz; selectable Fast output always enabled, 125Hz response (J3 Pin 3).

Step-Response Settling Times for the 3741 (in milliseconds)

	3db Frequency	To within 1%	within .1%	within .02%
Fast Output	125 Hz	4	8	10
Selectable Output	32 Hz	23	31	35
	8 Hz	93	125	140
	2 Hz	370	500	560

1.a PANEL MOUNTING

You can easily mount the instrument in your own precut panel. Cutout dimensions for a panel-mounted unit are standard DIN; panel thickness should not exceed 6 mm (0.24 in). Simply unscrew the two rear-panel CLAMP SCREWS and slide the CLAMP SLIDES rearwards out of their grooves (THE FRONT BEZEL NEED NOT BE REMOVED). Insert the unit through the panel cutout, from the front of the panel (if the unit has rubber feet, these will have to be removed). Then reinstall the CLAMP SLIDES, and tighten the CLAMP SCREWS until the instrument is securely mounted.

68 ± 0.7 mm (2.68 ± 0.03 in) 138 ± 1.0 mm (5.43 ± 0.04 in) CLAMP SLIDE CLAMP SCREW Panel Mounting

The Model 3741 I/O CONNECTIONS are via removable screw terminals which will accept wire sizes from AWG 12 to 26. NOTE: The recommended transducer cabling would be individually shielded, twisted pair or Coax cable - wired as indicated (Fig. 6) Table 1 denotes screw terminal assignments.

Rear Panel Connection

N/C N/C HOLD TARE TARE ENABLE LOGIC COM R CAL 5V SELECT + TORQUE IN - TORQUE IN + EXCITATION - EXCITATION 0.1 uF HF 10.0 uF DC + SIGNAL - SIGNAL EXC COMMON SHIELD VDC COM V OUT SEL V OUT FAST 4-20 mA COM 4-20 mA OUT POWER REQUIRED 90-250V ~ 47-63Hz 10W MAX DC Power Option POWER REQUIRED 9-36V= 10W MAX. + - +

Table 1

Connector Number	Screw Terminal	Label	Function
J1 1 N/C			No connection
J1 2 N/C			No connection
J1 3 HOLD			Input Analog Hold command
J1 4 TARE			Input Analog TARE command
J1 5 TARE ENABLE			External TARE Enable
J1 6 LOGIC COM			Logic Common
J1 7 R CAL			Remote Calibration command
J1 8 5V SELECT			5V enable for Torque Input signal
J1 9 + TORQUE IN			+ Torque Signal from conditioner
J1 10 - TORQUE IN			- Torque Signal (Analog Common)
J2	1	+ EXC	+ Excitation Power
J2	2	- EXC	- Excitation Power
J2	3	0.1 uf	High Frequency Noise suppression capacitor
J2	4	10.0 uf	DC Offset capacitor
J2	5	+ SIGNAL	Positive signal input from sensor
J2	6	- SIGNAL	Negative signal input from sensor
J2	7	EXC COMMON	Excitation Common reference
J2	8	SHIELD	Case Shield for cable termination
J3 1 VDC COM			- Signal Output Voltage Common
J3 2 V OUT SEL			+ Signal Output Voltage – Filter Select
J3 3 V OUT FAST			+ Signal Output Voltage – 125 Hz
J3 4 4-20 mA COM			Filter Current Output Common
J3	5	4-20 mA OUT	Current Output Signal

Horsepower Connections. When utilizing the Model 3741, the frequency sensor source will be the same as the "Speed" conditioner source that is connected to the RPM meter, typically the Model 3740. Connect the frequency input to the 3740 and 3741 meters as shown in the frequency connections later in this manual depending on the type of sensor that is being utilized. The "Torque" input source for the Horsepower measurement will originate from the Torque conditioner, typically the Model 3770 or 3778 DC & AC Strain Gage meters. The conditioned analog signal from the Torque meter will be connected to J1-9 & J1-10 of the Model 3741 unit as shown in the overview diagram below. When connecting signals between meters it is recommended to used twisted pair, shielded cable with the "shield" connection (or J1-Pin 6 terminal).

graph TD
    A["Speed Pickup for RPM"] --> B["3740"]
    B --> C["3741"]
    C --> D["3778"]
    D --> E["Torque Sensor"]

    subgraph 3740
        F["NC NC HOLD TARE ENABLE LOGIC COM R CAL NC NC NCC + EXCITATION - EXCITATION 6.1μF HT 10.0μF DC + SIGNAL - SIGNAL EXC COMMON SHIELD VDC COM V OUT SEL VOUT FAST 429 mA COM 420 mA OUT"]
    end

    subgraph 3741
        G["NC NC HOLD TARE ENABLE LOGIC COM R CAL 5V SELECT + TORQUE IN - TORQUE IN + EXCITATION - EXCITATION 0.1μF HF 10.0μF DC + SIGNAL - SIGNAL EXC COMMON SHIELD VDC COM V OUT SEL VOUT FAST 420 mA COM 428 mA OUT"]
    end

    subgraph 3778
        H["SYN: W/S ENABLE HOLD TARE TABLE ENABLE LOGIC COM R CAL + R CAL SHUNT SHUNT-W"]
        I["+ EXCITATION - EXCITATION + SENSE + SIGNAL - SIGNAL CAL SENSE SHIELD VDC COM V OUT SEL V OUT FAST 428 mA COM 428 mA OUT"]
    end

Note: For the torque meter connections, refer to the Model 3770 or 3778 manual.

WARNING

Qualified personnel who work on or near exposed energized electrical conductors must follow applicable safety related work practices and procedures including appropriate personal protective equipment in compliance with the Standard for Electrical Safety Requirements for Employee Workplaces (ANSI/NFPA 70E-2012) of USA and any additional workplace safety requirements applicable to your installation.

2 CONNECTIONS

J1 - HOLD, TARE, RCAL & 5V SELECT Connections. These Logic connections are used when external control of these features are enabled or controlled by an external switch, PLC or relay. The input Command signals are activated when connected to LOGIC COMMON and will affect the display and analog output signals present on J3.

Fig. 5
J1 Logic Controls

Push Button, Contact Relay, Switch...... HOLD TARE TARE ENB LOG COM + REMOTE CAL 5V Select Connected to LOGIC COMMON TARE

HOLD * Activates Analog HOLD when connected to LOGIC COMMON
TARE * Activates Analog TARE when connected to LOGIC COMMON TARE
ENABLE * Enables remote TARE when connected to LOGIC COMMON LOGIC
COMMON Connection to enable rear panel features
REMOTE CAL Activates the Fixed Frequency Calibration when connected to LOGIC COMMON
5V SELECT When connected to LOGIC COMMON, designates 5 V full scale input of the Torque signal
* NOTE: TARE & HOLD are general 3700 Instrument feature, For the Model 3741 it has limited use due to the frequency content within the FAST analog signal which is used in the TARE & HOLD circuit and may be un-repeatable in its use - it is recommended not to use this feature.

Model 3741 Transducer Cabling - Typical Magnetic Pickup

A + SIGNAL + FREQUENCY SOURCE - B - SIGNAL + EXCITATION - EXCITATION 0.1 uF HF 10.0 uF DC + SIGNAL - SIGNAL EXC COMMON SHIELD

Typical Wiring Hookup for a standard Magnetic Pickup for Speed / Flow Measurements

SUPPRESSION OF HIGH-FREQUENCY NOISE IN LOW-FREQUENCY INPUT (0.1-μF)

False triggering can sometimes occur, especially at the low-frequency input range, because of stray pickup of frequencies outside the common-mode range. Capacitive coupling of the frequency input to ground can in such cases serve to suppress unwanted signal noise. This noise suppression is always recommended when using a two wire MAGNETIC PICKUP as the frequency source. Thus, if you find your frequency reading to be unacceptably unstable or "noisy," it is recommended to tie the 0.1- F pin to EXC COM & -SIGNAL; maintaining the normal +SIGNAL connection.

2 CONNECTIONS

FREQUENCY SOURCE + - 10K Pull Up Resistor + EXCITATION - EXCITATION 0.1 uF HF 10.0 uF DC + SIGNAL - SIGNAL EXC COMMON SHIELD

Ungrounded Frequency Source

PULL-UP RESISTOR

When used with an open-collector type sensor, the 3741 requires a pull-up resistor (typically 10 kOhm) between the +SIGNAL and the + EXCITATION terminals.

Zero-Velocity Sensor

Configured for + 12 Vdc powered device Zero-Velocity Sensor + Power - Power + Signal EXCITATION - EXCITATION 0.1 uF HF 10.0 uF DC SIGNAL + - SIGNAL EXC COMMON SHIELD

EXCITATION + EXCITATION 0.1 uF HF 10.0 uF DC SIGNAL + SIGNAL EXC COMMON SHIELD Tie - SIGNAL & EXC COM to 0.1 uF pin for suppression of high-frequency noise issues Connect the Sensor's + SIGNAL to 10 uF pin to eliminate DC Offset Tie - SIGNAL to EXC COMMON II - SIGNAL is not grounded at the source

Wiring Options for DC Offset and High Frequency Noise issues

ELIMINATION OF DC OFFSET (10-μF)

The 3741 is supplied with two capacitive-coupled terminal inputs, 0.1- and 10-microFarad capacitance. These special inputs would not normally be used with zero-velocity sensors requiring 10-12 Vdc excitation. The larger (10- F) capacitive coupling can be used to eliminate any positive or negative DC offset that exists for a 3741 input frequency signal. Simply connect the +SIGNAL line from the frequency source to the 10- F terminal instead of to the normal +SIGNAL terminal. The capacitor is then in series with the +SIGNAL input and allows only AC to pass. Note: Only for configurations of 10V logic levels or less.

2 CONNECTIONS

J3 - Analog Connections. Connections are used to provide analog outputs from the meter's signal conditioning area in the form of +/- 5VDC or +/- 10 VDC (selectable via the front panel controls) and 4-20 mA.

graph TD
    A["Analog Voltage Output +/- 5 Vdc or +/- 10 Vdc with fixed cutoff filter @ 125 Hz"] -->|+ SIGNAL| B["Terminal Block 1"]
    A -->|- SIGNAL| C["Terminal Block 2"]
    D["Analog Voltage Output +/- 5 Vdc or +/- 10 Vdc with front panel selectable filter @ 2 / 8 / 32 Hz"] -->|+ SIGNAL| E["Terminal Block 3"]
    D -->|- SIGNAL| F["Terminal Block 4"]
    G["Analog Current Output 4-20mA at selected cutoff filter"] -->|+ SIGNAL| H["Terminal Block 5"]
    G -->|- SIGNAL| H

Analog Output Connections

VDC COM - Pin 1 Voltage Common (- Signal out); Negative reference for Pin 2 and Pin 3 Voltage Output.

V OUT SEL - Pin 2 Voltage Output Selected (+Signal out) reference to Pin 1. The Full Scale Voltage is determined by the position of switch 1 - VDC on the Conditioner Controls. Voltage Filter output response of this signal is determined by the position of switch 3 - FIL and 4 - FIL on the Analog Controls.

V OUT FAST - Pin 3 Voltage Output Fixed. (+ Signal out) reference to Pin 1. Full Scale Voltage is determined by the position of switch 1-VDC of the Conditioner Controls. Filter response is fixed at the highest analog signal response of 125 Hz.

4-20mA COM - Pin 4 4 - 20 mA Current Output Common (- Signal) reference for Pin 5 Current output.

4-20mA OUT - Pin 5 4 - 20 mA Current Output (+Signal) reference to Pin 4 Current Output Common. Mode of the Current Output.

3

CONTROLS

Digital Display Range and Decimal Point Selection

Configures the Engineering Unit's Digital Display Range. Three selections are available to set the display operation for 1 count in 5000, 2 counts in 10000 or 5 counts in 20000. These full scale ranges correspond to the analog output full scale value of ± 5 VDC or ± 10 VDC as selected when the Display Span control is set to the "OFF" position (see below).

1. X. X. X. X 0 ÷1 9 9 9 5 0 FINE ADJUST ZERO SPAN F C F 1 X.X.X.X 0 5000 ↓ ↓ 1 2 3 4 5 6 7 10000 ↑ ↓ 20000 ↓ ↑

Switch 1 - selects decimal point for position X.XXXXX

Switch 2 - selects decimal point for position XX.XXXX

Switch 3 - selects decimal point for position XXX.XXX

Switch 4 - selects decimal point for position XXXX.XX

Switch 5 - enables dummy zero display digitXXXX0

Switch 6 & 7 - selects Display Full Scale Range.

Display Span Adjustments

Used to adjust the digital readout of the 3741 meter independently of the analog signal when not in the “OFF” position. After setting the analog FS output signal level, the user rotates the Display SPAN Coarse controls (F) and adjust the Display Fine (F)control for proper engineering units display. Example: adjust the analog output for maximum full scale analog output. Once achieved, rotate the Display “C” control from “OFF” (F position on the switch) to the desired Horsepower measurement on the display. Use the Display SPAN “F” control for fine adjustment of the readout. If needed, use the display's 5000, 10000 or 20000 unit's selection as shown above to achieve the proper reading.

DISPLAY SPAN C F OFF RCAL

Display Coarse Span - 16 position switch to adjust wide zero authority

Display Fine Span - 25 Turn potentiometer for fine span control of analog signal

Display "OFF" - switch position "F" - "OFF" which disables the Display Span feature

3 CONTROLS (cont.)

Analog Control Settings

Analog Control - 7 position switch configures the main parameters of the AC Signal conditioner for required output voltage level, low pass filter characteristics and input signal sensitivity level.

For the initial setup of the 3741 Meter, the switch settings should be the same as the "calibrated" 3740 RPM meter settings, including Wide-Adjust Range - Span switch positions.

FINE ADJUST ZERO SPAN F C F 1 X X X X Ø 5000 ↓ ↓ 10000 ↑ ↓ 20000 ↓ ↑ RANGE SPAN 1 2 3 4 5 6 7 WIDE ADJUST ANALOG CTRL

1 - 5 VDC Output - UP sets the analog output FS to 5 VDC, DOWN is 10 VDC

2 - Not Used

3 - 8/32 Hz - UP selects 8 Hz filter. DOWN selects 32 Hz filter

4 - 8/2 Hz - UP selects 8 Hz filter. DOWN selects 2 Hz filter

5 - SENSITIVITY A - UP selects 0.25 - 10.0 V, DOWN selects 0.05 - 2.0 V

6 - SENSITIVITY B - UP selects 0.25 - 10.0 V, DOWN selects 1.0 - 40.0 V

7 - SENSITIVITY C - UP selects 0.25 - 10.0 V, DOWN selects 5.0 - 250.0 V

With all of the switches in the up position, the unit will have the following settings:

• The full scale analog output will be 5.000 VDC
- The selected analog output - low pass filter will be set for 8 Hz
- Input voltage sensitivity detect (least positive value of wave shape) is 0.25 to 10V .

Analog Control Settings for Conditioner Configuration

↑	Function	Down ↓
5	1 - VDC OUT	10
	2 - not used
8 Hz	3 - FILTER	32 Hz
8 Hz	4 - FILTER	2 Hz
.25-10	5 - SEN A	.05-2.0
.25-10	6 - SEN B	1.0-40
.25-10	7 - SEN C	5.0-250

Analog Control Settings (red switch)

The 7 position front panel analog control switch will configure the signal conditioning section of the meter. The position of the switches will depend on the type of sensor, it's parameters and the expected analog output signal Full Scale level - along with the output signal's 3db roll-off response characteristics.

3 CONTROLS (cont.)

Input Frequency Range & Span Wide-Adjust Controls

Two rotary control switches are used to set the nominal input frequency range of the input signal. Ranges are 250 Hz to 128 KHz Full Scale which corresponds to the of the analog output signal of the 3741 meter. Note the 3741 meter, when used with the 3740 meter, should have the same Range and Span Wide adjust settings for initial setup.

FINE ADJUST ZERO SPAN F C F 1 X X X X Ø 5000 ↓ ↓ 10000 ↑ ↓ 20000 ↓ ↑ RANGE SPAN 1 2 3 4 5 6 7 WIDE ADJUST ANALOG CTRL

Range Wide-Adjust - 10 position switch to adjust input range full scale - 250 Hz .... 128 KHz

Span Wide-Adjust - 16 position switch to adjust range authority between the selected ranges

Due to multiple amplifier stages within the 3741 instrument, attention to the proper gain setting and understanding of the sensor inputs should be reviewed to produce a linear-amplified analog output signal and display reading.

The Range & Span Wide-Adjust–gain control (as shown in the front panel diagram) amplify the incoming conditioned signal by incremental steps. Each step is positioned so the front panel accessible Coarse and Fine Span potentiometer controls overlap each step to provide a continuous linear gain of the signal from 250 Hz to 128 KHz full scale.

Range Wide-Adjust - 10

Position switch for adjustment of the full scale frequency input range. Also sets the 80% value for the RCAL switch. X2 gain per step

Span Wide-Adjust - 16

Position switch for adjustment of the frequency input between the Range Wide-Adjust switch position. Approx. X 4.8% gain change per step.

3741 Horsepower configuration of the Wide Adjust Controls should match the 3740 Frequency meter on initial setup. Further adjustment can be made once the Speed and Torque readings are established and calibrated.

The Horsepower "Span" adjustment should involve only minor correction from this reference point unless maximizing the analog output is required. If this is the case, reference the "Display Span Adjustment" control features as shown on page 8.

3 CONTROLS (cont.)

Fine Zero, Coarse Span and Fine Span Adjustments

Front panel potentiometer controls for the fine adjustment of the zero and gain setting of the analog output signal of the 3741 meter. The controls are present when the front panel is re-installed for user fine tuning adjustment as needed to maintain calibration of the measurement once the unit has been configured via the analog controls.

FINE ADJUST ZERO SPAN 5000 1 2 3 4 5 6 7 1. X. X. X. X. 10000 20000 RANGE SPAN 1 2 3 4 5 6 7 WIDE ADJUST ANALOG CTRL

Fine Zero - 25 Turn potentiometer for fine balance control of analog signal

Coarse Span - 22 Turn potentiometer adjustment for analog control of gain

Fine Span - 25 Turn potentiometer adjustment for analog control of gain

Remote Calibration

DISPLAY SPAN C F OFF RCAL

R CAL Remote / Reference Calibration - Momentary switch - when depressed connects an internal clock reference to the SPAN circuit as a reference to set or check calibration of the 3741 unit. R CAL can also be activated via the rear panel connection when Remote CAL is connected to logic common. R CAL frequency is determined by the setting of the Wide Range control switch and will represent 80% of the setting of the RPM signal. Proper activation of the Torque input is required for RCAL to function properly.

4. CALIBRATION - 2 Point - with known inputs

This section contains the instructions for calibrating the 3741. Reference the description of the instrument front-panel and Analog Controls for initial setup. Prior to calibration of the 3741 Meter, the source inputs of RPM & Torque require calibration. Please refer to the seperate 3740 and 3770/3778 manuals for these procedures. When these measurements are established, proceed as follows.

(a) Connect Power, Sensor and Analog terminals as required. Apply power. The front-panel digital display should light indicating the application of the AC input power. Allow 10 minutes of warm up for stabilization of the instrument and sensor. Remove the front panel cover of the 3741 unit which is held in place by the two small Phillips screws.
(b) Position the front panel switches to the same settings as the 3740 meter. Refer to Section 3 for details.
(c) Center the Fine Zero and Span potentiometers as needed by rotating the potentiometers fully CW (Coarse is 22 turns, Fine is 25 turns), then reverse direction - CCW (Coarse 11 turns and Fine 13 turns) to obtain mid-authority of the controls. Typically this is done on initial calibration. When recalibrating for minor adjustments this may not be required.
(d) With a known Zero (Zero Torque or Zero Speed or both) Adjust Fine Zero for the Zero position reading on the display or the desired analog output signal. Note: Display can be adjusted independently to the analog signal when the Coarse Display control is not in the "OFF" position.
(e) Calculate your Horsepower "Span" point for the given calibration RPM & Torque values.
(f) Apply the known frequency or sensor input to the 3741 meter, typically at full scale or nominal working range. Apply a torque input using Shunt Cal or known input to the torque meter within the nominal working range of the torque meter. With both inputs active, adjust the Wide Span controls and Fine Span controls for the proper Horsepower reading as calculated for the input value given. If greater control is needed, utilize the display 5000, 10000 or 20000 settings.
(g) Return the input signal to the Zero position in step (d) and re-adjust the Zero controls as needed to obtain the proper reading (or analog signal) for the application's zero position.
(h) Re-Apply the known frequency and torque signals and re-Adjust the Coarse Span and Fine Span controls, as needed, for precise engineering units reading on the display as well as the analog output desired.
(i) Repeat Steps (g) and (h) to obtain proper measurement readings since the Gain - Span controls will affect the Zero amplification of the input signal.
(i) Re-install the front panel. Fine Span and Zero controls are accessible with front panel installed.

Note: RCAL on the 3741 unit simulates 80% of the full scale of the frequency signal only. An active "torque" or "shunt cal" input from the torque meter is required to produce a Horsepower reading for calibration reference.

Useful Horsepower calculations

Using ft.lbs HP = Torque (ft.lbs) x RPM / 5252

Using in.lbs HP = Torque (in.lbs) x RPM / 63025

Using Newtons HP = Torque (newton meters) x RPM / 7121

Horsepower (metric) = Horsepower (english) x 1.014

Newton-meters = ft.lbs x 1.3558

Tech Tip for the Frequency Conditioner

The 3741 Frequency Panel meter and conditioner has selectable low pass filter settings which are configured via the Analog Control Switch located behind the front panel of the instrument. The proper filter setting will depend on the application and the dynamic response needed for the analog output signal. Use the following table as a guide in determining the most appropriate Range and Filter setting. The table is referenced by the expected stability / AC content “bleed through” from the input signal when at low frequency levels. Utilizing a 9 pole filter enhances the analog tracking of the incoming frequency signal to very low levels compared to traditional F/V converters. Note the FAST signal output is always present on J3-3.

Filter Setting effect per Input Range for low end stability of the analog output signal Input Level - 50 mV P-P Sine Wave: Output - +/ 5 mV signal content level (0.1% FS) (x = unusable)

Filter Setting

	2 Hz	8 Hz	32 Hz	Fast
0 250	10	40	175	x
1 500	10	36	160	x
2 1000	10	34	150	x
3 2000	10 30		136	810
4 4000	10	26	125	680
5 8000	10	22	115	600
6 16000	10	22	100 530
7 32000	10	22	90	480
8 64000	10	22	175	950
9 128000	10	22	340 1900

Range Fullscale in Hertz
Low End Input in Hertz

DAYTRONIC 3770 DC STRAIN +5637 C F C F ZERO SPAN +CAL CAL TAPE DAYTRONIC 3740 FREQUENCY METER +4200 T O F ZERO SPAN CAL DAYTRONIC 3741 HORSEPOWER METER +4508 F E F ZERO SPAN CAL

Typical Horsepower system with a 3703 Rack panel

3770 or 3778 Meter DC or AC Strain Gage Conditioner for Torque

3740 Meter Frequency Conditioner for Speed

Should you suspect a blown fuse proceed as follows.

WARNING

Installation, operation and maintenance of this instrument must be performed by qualified personnel only. The National Electrical Code defines a qualified person as “one who has the skills and knowledge related to the construction and operation of the electrical equipment and installations, and who has received safety training on the hazards involved.”

a) Disconnect all power sources and cables connected to the instrument before servicing the instrument.
b) On the rear panel remov ve the (2) clamp slide retaining screws and remove the clamp slides from both sides of the instrument. Next remove the (4) corner screws that retain the rear panel to gain access to the instrument.
c) Open the rear panel and replace the fuse(s) as required, replace only with same type T Slow Blow, 1A, 250V (Littelfuse 218001.HXP, 1 A). The fuseholder wire conductors are appropriately labeled "L" for Line and "N" for Neutral on both halves of each of the fuseholder wires. When reassembling the fuseholder(s) make sure "L" and "L" are connected together and "N" and "N" labeled wires are connected together properly.
d) Mate the rear panel to the enclosure and replace the clamp slides back in position and secure the clamp slides with the (2) screws previously removed from the instrument. Next, replace the (4) corner screws to secure the rear panel and ensure that all screws have been adequately tightened.
e) Power ON the instrument with the appropriate power cord and verify the instrument is functioning properly before reconnecting the instrument to your installation.

WARNING

For continued protection against risk of fire or shock replace only with the same type and rating of fuse.

ADVERTENCIA

Do not replace fuse again if failure is repeated. Repeated failure indicates a defective condition that will not clear with replacement of the fuse. Refer condition to a qualified technician.

ADVERTENCIA

Product Warranty and Repair

Daytronic Corporation warrants its products to be free from defects in material and workmanship, under normal and proper use in accordance with our instructions, for the period of one year for date of shipment. Our liability under such warranty or in connection with any other claim relating to the products shall be limited to, at our option, the repair or replacement of any products or parts or components thereof which are returned to us freight prepaid and which are defective in material or workmanship or the refund of the purchase price to the Buyer.

ANY PRODUCT FOUND TO BE DAMAGED THROUGH CUSTOMER NEGLIGENCE OR MISUSE MAY BE EXCLUDED FROM ANY AND ALL POLICIES CONTAINED IN THIS DOCUMENT.

ALL EQUIPMENT TO BE REPAIRED OR REPLACED UNDER WARRANTY MUST BE RETURNED TO THE FACTORY. Before returning a product or products for any reason, the customer must call Daytronic Customer Support Services at [phone] to request a RETURN MATERIAL AUTHORIZATION (RMA). Once the customer has provided the necessary information and has been assigned a specific RMA, the product(s) in question may be returned to Daytronic by shipping it

Daytronic Corp., 1000 New Durham Road, Edison, New Jersey 08818 Daytronic Customer Service: 1-800-668-4745 [e-mail]

DAYTRONIC

Daytronic Corporation Dayton OH USA

www.Daytronic.com