gle/SG-IsoCond01
Isolated signal conditioner strain gages transducers
Main Features • Isolated signal conditioner for strain-gage bridges, like load cells and pressure transducers (full-bridge). • Full-scale sensitivities of 1mV/V, 2mV/V, 3mV/V and 4mV/V. |
• 1500Vrms input/output isolation. |
Overview
gle/SG-IsoCond-01 is a highly accurate and cost-effective signal conditioner for single-channel strain gages and Wheatstone bridges in general like load cells and pressure transducers. The module accepts 350 Ohm (or greater) full-bridge gages providing the appropriate bridge excitation, signal filtering and conversion to a high level voltage output. Moreover gle/SG-IsoCond-01 has been designed to perform reliable internal isolation: voltages up to 2100 VDC (equivalent to 1500 Vrms) can drop between the input and the output stages of the conditioner (see the block diagram reported below).
Special protection circuits are also present on the signal input in order to prevent against pulsed over-voltages, undesired spikes and RF interferences. The same section also permits, via a trim pot, the zero fine adjustment and hence to offset eventual bridge imbalances.
An extremely stable 10 V source provides the needed voltage excitation for the transducers. This section comprises a series-type voltage regulator that outputs a high-stability voltage reference. Besides a screwdriver adjustable trim pot enables fine tuning around 10 V.
The amplification stage includes a precision monolithic differential amplifier. By means of dip-switches it is possible to select one of four pre-configured gain values (standard sensitivities corresponds to 1, 2, 3 and 4 mV/V). Isolation between the input and the output stage is provided by an isolation module downstream the amplifier (Isolation barrier in the block diagram) and by a high isolation DC/DC converter.
Eventual spurious signals can be filtered out thorough a 4th order low-pass active filter (standard cut-off frequency is equal to 10Hz), while module output is either voltage (0¸5 V) or current (4¸20 mA). For both these output options zero and gain fine adjustments are available using on-board potentiometers. Isolation is guaranteed also between the output stage and the primary voltage supply, assuring protection up 500 VDC (350 Vrms).
Output signals and power lines are connected to the unit by a 7-pins rugged bayonet connector, while input signals and transducer excitation enter in the module via gland and they are secured by means of a removable screw connector. gle/SG-IsoCond-01 housing is made of a rugged IP65 metallic case enabling usage even in extreme environmental operating conditions.
Block Diagram
Technical Specifications- gle/SG-IsoCond01
|
Input channels |
1 |
|
Transducer type |
Full bridge sensor |
|
Bridge load resistance |
³ 350 W |
|
Input impedance |
> 10 MW |
|
Common mode rejection ratio CMMR |
> 100 dB |
|
Input over-voltage |
± 40 V (not destructive) |
|
Gain selectable values |
500, 250, 166.7 and 125 (corresponded to 1mV/V, 2mV/V, 3mV/V and 4mV/V)* |
|
Gain selection |
Through dip-switches |
|
Stability |
± 50 ppm/°C rto; ±1 ppm/°C rti |
|
Bridge balance |
Via screwdriver adjustable trim pot |
|
Transducer excitation |
10 Vcc; high stability (8.5 ppm/°C); 2 wires with fine tuning |
|
Output signal |
1. Voltage: 0¸5V 2. Current: 4¸20 mA |
|
Output type selection |
Through dip-switches |
|
Output filter |
4th order active low-pass; cut-off frequency = 10 Hz |
|
Maximum loop load resistance (4¸20 mA output) |
450 W (without auxiliary power source) |
|
Adjustability |
±5% Zero and span |
|
Accuracy (@ 25°C) |
0.05% (linearity, hysteresis, repeatability and sensor excitation included) |
|
Input/Output isolation |
1500 Vrms |
|
Output/Power supply isolation |
350 Vrms |
|
Isolation Mode Rejection IMR |
> 100 dB @ 50Hz |
|
Power supply |
18 ¸ 36 VDC (Current absorption @ 100 mA @ 24 VDC) |
|
Transducer connector |
Removable screw terminals (cable enter in the case via gland). |
|
Primary voltage supply and output connector |
7-pins bayonet |
|
Operative temperature |
-40 ¸ +80 °C |
|
Housing |
Metallic IP65 case |
|
Dimensions |
80 x 125 x 57 [mm] (glands excluded) |
|
* Other gain options are available on request |
|
Due to continuous developments, specifications are subject to change without prior notice. This product is not intended for applications whose its failure to perform can be expected to cause damages to properties and/or persons and/or injury to human life.
Slider
