General
Number of analogue inputs	8
Input type	differential
Input voltage range	0 to 10 VDC
Resolution	16 Bit
Total sampling rate	40 kHz
Sampling rate per channel	5 kHz
Input impedance	min. 20 MΩ
Measurement accuracy at 25 °C	±0,1 % FSR
Measurement accuracy at -40 to 75 °C	±0,3 % FSR
Data buffering per channel	60 KB
Buffer duration at 5 kHz	6 Seconds
Connection type	Spring clamps (Euroblock)
Insulation	3 kVDC or 2 kVrms
Digital output - pulse frequency	up to 5 kHz
Electricity consumption	521 mA @ 24 VDC
Operation temperature	-40 to 75 °C
Storage temperature	-40 to 85 °C
Air humidity	5 to 95 % (non-condensing)
Elevation	up to 2000 m
EMC certification	EN 55032/24, EN 61000-6-2/-6-4
EMI certification	CISPR 32, FCC Part 15B Class A
EMS certification	ESD: 6 kV contact, 8 kV air; RS: 5100–6000 MHz, 3 V/m; EFT: 1 kV (power), 0.5 kV (signal); Surge: 2 kV (power), 1 kV (signal); CS: 10 V; PFMF
Railway certification	EN 50121-4, partially compliant with EN 50155
Safety certification	UL 508
Shock resistance	IEC 60068-2-27
Vibration test	IEC 60068-2-6
MTBF	1.426.112 Hours (Telcordia SR332)

The 85M-3811-T is an industrial-grade analog input module of the ioPAC 8500/8600 series by Moxa, specifically designed for use in demanding, harsh environments. It features 8 differential input channels and enables precise measurement of voltages in the range of 0 to 10 VDC. The module has a compact form factor designed for integration into modular control systems, with spring clamp terminals (Euroblock) allowing fast and reliable wiring with cables in cross-sections from 14 to 28 AWG. The module is designed for operation in an extended temperature range of -40 to 75 °C, making it suitable for industrial applications under extreme environmental conditions.

Applications

The module is used in industrial automation systems where high measurement accuracy and reliability under harsh operating conditions are required. Typical application scenarios include monitoring process variables such as pressure, temperature, or flow rates, which are converted into voltage signals via appropriate sensors. The high sampling rate and integrated data buffering make it particularly suitable for applications requiring time-critical data analysis, diagnostics, or traceability of measured values, for example in production monitoring or railway technology.

Functions and Features in Detail

The module offers a measurement accuracy of ±0.1 % FSR at 25 °C and ±0.3 % FSR across the full operating temperature range of -40 to 75 °C. The 16-bit resolution ensures fine resolution of measured values. The sampling rate is 40 kHz overall, with each channel reaching up to 5 kHz. The differential input configuration minimizes interference from electrical noise and ensures precise signal processing. The input impedance is at least 20 MΩ, ensuring high signal integrity and low sensor loading.

Technology Explained Simply

The integrated data buffering of 60 KB per channel allows storage of historical measurement data. At a sampling rate of 5 kHz per channel, up to 6 seconds of measurement data can be stored. This function is useful for analyzing short-term events or disturbances without requiring external storage or a permanent network connection. The isolation of 3 kVDC or 2 kVrms protects the module and connected systems from electrical overvoltages. The digital output can generate pulse frequencies up to 5 kHz, which can be used for control tasks.

Compatibility and Accessories

The module is part of the ioPAC 8500/8600 series and is used in modular control systems. It is compatible with industry and railway technology standards, including EN 50121-4 and partially EN 50155, enabling its use in railway applications. Certifications include EMC and EMI standards such as EN 55032/24, CISPR 32, and FCC Part 15B Class A, as well as EMS tests such as ESD, RS, EFT, Surge, and CS. The safety certification UL 508 confirms compliance with safety requirements for industrial control equipment.

Mounting and Installation

The module is mounted in standard 19-inch racks or modular control systems. The spring clamp terminals allow quick and secure connection of I/O cables. The compact design with dimensions 25 x 128.2 x 85.5 mm and a weight under 80 g facilitates placement in limited installation spaces. The operating temperature range of -40 to 75 °C and humidity of 5 to 95 % (non-condensing) enable use in a wide range of environments, including outdoor use or in industrial halls with high temperature fluctuations.

Operational Advantages

The high measurement accuracy, fast sampling rate, and integrated data buffering offer advantages for real-time monitoring and diagnostics of processes. The differential input configuration reduces interference and improves signal quality. The isolation protects the system from electrical disturbances. The certifications according to industry and railway standards ensure reliability in critical applications. The 5-year warranty underscores the high quality and longevity of the module.

MTBF

The mean time between failures (MTBF) is 1,426,112 hours according to Telcordia SR332, highlighting the high reliability and long service life of the module.