ETC 2B54

Four-Channel, Isolated
Thermocouple/mV Conditioners
Models 2B54/2B55
Low Cost Per Channel
Wide Input Span Range: ±5mV to ±100mV (2B54)
±50mV to ±5V (2B55)
Pin Compatible with 2B34 RTD Conditioner
High CMV Isolation: ±1000V dc; CMR = 156dB min @ 60Hz
Low Input Offset Voltage Drift: ±1µV/°C max (2B54B)
Low Gain Drift. ±25ppm/°C max (2B54B)
Low Nonlinearity: ±0.02% max (±0.012% typ)
Normal Mode Input Protection (130V rms) and Filtering
Channel Multiplexing: 400 chan/sec Scanning Speed
Solid State Reliability
Multichannel Thermocouple Temperature Measurements
Low and High Level Data Acquisition Systems
Industrial Measurement and Control Systems
Models 2B54 and 2B55 are low cost, high performance, four-channel
signal conditioners. Both models are functionally complete, providing
input protection, isolation and common mode rejection, multiplexing,
filtering and amplification.
The 2B54 has been designed to condition low level signals (±5mV to
±100mV), like those generated by thermocouples or strain gages, in the
presence of high common mode voltages. The 2B55 is optimized to
condition ±50mV to ±5V or 4 to 20mA transmitter signals as inputs.
The four-channel structure of both models results in significant cost
and size reduction.
The high performance of the 2B54 and 2B55 is accomplished by the
use of reliable transformer isolation techniques and an amplifier-perchannel architecture. Each of the input channels is galvanically isolated
(±1000V dc) from the other input channels and from output ground.
The amplifier-per-channel structure is used to obtain low input drift
(±1µV/°C max, 2B54B), high common mode rejection (156dB @
60Hz), and very stable gain (±25ppm/°C max). Other key features
include low input noise (1µV p-p), low nonlinearity (±0.02% max) and
open-thermocouple detection (2B54).
Models 2B54 and 2B55 were designed to serve as a superior
alternative to the relay multiplexing circuits used in multi-channel data
acquisition systems, computer interface systems, process signal
isolators, and temperature measurement and control instrumentation.
Advantages over relay circuits include functional versatility, superior
performance, and solid state reliability. Both models are also pin
compatible with the 2B34, four-channel RTD/strain gage conditioner.
In thermocouple temperature measurement applications, outstanding
low drift, high noise rejection, high throughput and 1000V isolation
make the 2B54 a natural choice over flying capacitor multiplexers
in conditioning any thermocouple type.
Information furnished by Intronics is believed to be accurate and reliable. However, no
responsibility is assumed by Intronics for its use; nor for any infringements of patents or
other rights of third parties which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Intronics.
When cold junction compensation is required in measurement of
temperature with thermocouples, the 2B54 may be used directly
with the model 2B56 Universal Cold junction Compensator.
High Reliability: To assure high reliability and provide isolation
protection to electronic instrumentation, reliable transformer
isolation and solid state switching are used. Both models have been
conservatively designed to meet the IEEE standard for Transient
Voltage Protection (472-19 74: SWC) and offer 130V rms normal
mode input protection.
High Noise Rejection: To preserve high system accuracy in
electrically noisy industrial environments, the 2B54 and 2B55
provide excellent common mode noise rejection, RFI/EMI
immunity, and low pass filtering for rejection of series mode noise
and 50Hz/60Hz pickup.
Ease of Use: The multichannel, functionally complete design in a
compact (2" X 4" X 0.4") module, assures case of use, conserves
board space and eliminates the need for a number of discrete
components necessary in relay multiplexing circuits.
Low Cost: The 2B54 and 2B55 offer the lowest cost per channel
for isolated. solid state. low level signal conditioners.
1400 Providence Highway, Building #2
Norwood, MA 02062
Phone (781) 551-5500
FAX (781) 551-5555