Foxboro Evo FBM237 Analog Output Module

Foxboro Evo FBM237 Analog Output Module

The FBM237 contains eight 0-20 mA analog output channels. In situations where control system reliability is important, the FBM237 may have a redundant module installed. This permits all eight outputs to maintain operation in the presence of a single fault and during the time that the suspect module is removed and replaced. The 0-20 mA signals are electrically compatible with HART ®  field devices.

Module core functions and features

FBM237 is an 8-channel galvanized isolated 0~20mA analog output module. Its core design revolves around high reliability, flexibility, and compatibility. The key functions and features are as follows:

（1） Core functions

Multi scenario output capability:

Output range: 0~20.4mA DC (out of range design, compatible with standard 0~20mA actuators), single channel maximum load of 750 Ω, meeting the driving requirements of most industrial field equipment;

HART compatibility: The channel impedance meets the requirements of HART high impedance devices, can be connected to a HART handheld communicator (HHC), does not interfere with HART signal transmission, and supports intelligent device debugging and diagnosis.

Redundant deployment and failover:

Redundancy mode: Two FBM237s form a redundant pair and need to be installed in adjacent odd/even positions on the base (such as 1&2, 3&4), in conjunction with the redundant adapter RH916QD to achieve signal sharing;

Fault handling: Synchronize output commands through the AOUTR function block of Foxboro Evo control software. When a single module fails, automatically drive the fault channel current to 0mA. Normal modules seamlessly take over, and replacing faulty modules does not interrupt on-site output.

Safety and protection design:

Channel isolation: Each channel is Galvanically isolated from other channels and ground, withstanding 600V AC (1 minute) to avoid interference between channels and ground faults;

Current limit: The maximum output current of a single channel is about 25mA to prevent overload damage to the actuator;

Fail Safe: Supports "Hold" or "Fallback" modes, with a configurable fallback value of 0mA to avoid the risk of "high output failure".

（2） Key characteristics

Environmental adaptability: Complies with ISA S71.04 G3 level harsh environmental standards, can withstand vibration (0.75g @ 5-500Hz), wide temperature range (working -20~70 ℃, storage -40~70 ℃), and is suitable for industrial high temperature and high dust scenes;

Hot plugging and maintenance: Module replacement does not require dismantling of on-site wiring, power or communication cables, and redundant module maintenance does not affect the operation of on-site equipment; Partial termination components (TA) with bypass sockets, supporting temporary output maintenance through bypass stations (such as P0900HJ);

Status indication: The front LED light provides real-time feedback on the communication status, power status, and channel faults of the module, making it easy to quickly locate problems;

Communication reliability: Connected to the fieldbus communication module (FCM) or control processor (FCP) through a 2 Mbps redundant fieldbus, supporting A/B dual path switching, and ensuring uninterrupted data transmission in case of single path failure.

Hardware parameters and technical specifications

（1） Output and precision parameters

Parameter category specific specifications

Channel configuration includes 8 independent channels, with each channel being Galvanically isolated (between channels, channel to ground)

Accuracy (including linearity) ± 0.05% range (within the range of 0.1~20mA), temperature coefficient ± 50 ppm/℃ (temperature changes have little impact on accuracy)

Maximum output delay of 30ms (meets the real-time requirements of most industrial controls)

Resolution of 13 bits (high output adjustment accuracy, supports fine control signal output)

Circuit power supply protection with independent current limitation and voltage regulation for each channel to avoid overload damage

The wiring distance depends on the compliant voltage (18V DC at 20.4mA), wire specifications, and equipment voltage drop, and supports a maximum of 30m cables

（2） Power supply and power consumption

Power input: 24V DC (redundant mode, allowable range+5%/-10%, i.e. 21.6-26.4V DC), requires independent redundant power supply;

Power consumption: Maximum 7W (running) at 24V DC, maximum heat dissipation of 5W, reserved heat dissipation space is required to avoid module overheating.

（3） Physical and environmental parameters

Parameter category specification requirements

Dimensions (module) height 102mm (including installation ears 114mm) x width 45mm x depth 104mm, single slot design

The weight module weighs approximately 284g (10oz); TA approximately 181-249g (0.40-0.55lb, depending on terminal type)

Working environment temperature -20~70 ℃, humidity 5%~95% (non condensing), altitude -300~3000m

Storage environment temperature -40~70 ℃, humidity 5%~95% (no condensation), altitude -300~12000m

The pollution level complies with EIA 364-65 Class III and is suitable for harsh environments with ISA S71.04 G3 level (high dust, high humidity)

Installation and Termination Component (TA) Configuration

FBM237 needs to be used in conjunction with a dedicated base, termination assembly (TA), and cables. Installation and wiring must follow strict specifications, with the following core requirements:

（1） Base and installation

Base type:

Modular base: Supports DIN rail (32mm/35mm) or 19 inch rack installation, with a maximum capacity of 8 FBM modules per base;

Redundant installation: Redundant modules need to be fixed in adjacent odd/even positions, connected to the base terminals through the redundant adapter RH916QD, to achieve two modules sharing one TA signal interface.

Installation specifications:

Heat dissipation space: Reserve ≥ 25mm space on each side of the module to avoid the influence of adjacent devices on heat dissipation;

Grounding requirements: Galvanized yellow chromium steel DIN rails are preferred for the base to ensure reliable grounding, and aluminum/plastic rails are prohibited (which may cause poor grounding).

（2） Termination Component (TA) Selection

TA is a key component connecting FBM237 with on-site actuators, providing signal switching and bypass maintenance functions. It needs to be selected according to the scenario, and the specific model and adaptation scenario are as follows:

TA model core function adaptation scenario authentication type

RH916YE (main TA) 8-channel signal transfer, no bypass function, normal scenario (no online maintenance required) Type 1/2 (compatible with hazardous areas)

RH917QZ (main TA) 8-channel with bypass socket, supporting bypass station access to critical scenarios (requiring online maintenance, such as chemical reaction kettle) Type 4/5 (ordinary area+Class 2 circuit)

TA connection: TA connects to the base through a Type 1 cable (25 pin D-sub interface), with a maximum cable length of 30m, supporting 2 materials:

P/PVC: polyurethane outer layer+PVC insulation, temperature range -20~80 ℃, suitable for ordinary industrial environments;

LSZH (Low Smoke Zero Halogen): Low smoke zero halogen release at high temperatures, suitable for enclosed environments such as ships and subways, with a temperature range of -40~105 ℃;

Wiring specifications: TA supports solid/multi strand wires of 0.2~4mm ² (24~12 AWG), and multi strand wires with wire ears should be 0.2~2.5mm ² (with or without plastic sleeves), with terminal torque in accordance with manufacturer specifications.

Compliance certification and security requirements

（1） Core certification

The FBM237 module and its supporting TA comply with global safety, electromagnetic compatibility, and environmental standards in multiple regions, with the following core certifications:

Specific standards and levels for certification categories

Hazardous Area Certification North America: UL/UL-C Class I Division 2 Groups A-D, Temperature Code T4;

Europe: ATEX 2014/34/EU II 3 G Ex nA IIC T4 (DEMKO certification, except RH917QZ);

International: Compliant with IECEx standards and suitable for Zone 2 hazardous areas

Electromagnetic Compatibility (EMC) EU EMC Directive 2014/30/EU, compliant with EN 61326-1:2013 Class A (Emission and Immunity in Industrial Environments)

Low Voltage Safety EU Low Voltage Directive 2014/35/EU, communication circuits comply with UL Class 2 standards (NFPA 70 Article 725, CSA C22.1 Section 16)

Environmental compliance complies with the EU RoHS 2011/65/EU directive, restricting the use of harmful substances such as lead and mercury

Ship certification ABS type approval, French Classification Society (BV) EC31 environmental category certification, applicable to ship automation systems

（2） Safety operation requirements

Electrical safety:

Isolation restriction: Although the module can withstand 600V AC, it is prohibited to connect to excessive voltage (such as 220V AC) for a long time to avoid insulation damage;

Wiring specifications: On site wiring should distinguish between positive and negative poles. In redundancy mode, ensure that the two modules have independent power supplies to prevent redundancy failure caused by single point power failure.

Dangerous area operation:

Shell requirements: It must be installed in a certified shell with a protection level of IP54 or above, and the shell must be opened with tools to prevent unauthorized operation;

Maintenance process: Power off or confirm that the area is in a non hazardous environment before connecting/disconnecting cables. Redundant module replacement should be carried out after the faulty module is powered off.

Upgrade and compatibility instructions

FBM237 is mainly used to replace the Foxboro 100 series FBM37 analog output module. When upgrading, the following compatibility points should be noted:

Hardware replacement: A single FBM237 can directly replace one FBM37, and on-site wiring can be reused in two ways:

Direct adaptation: Use the documentation to specify the TA (such as RH916YE) and rewire it to the TA terminal;

Adapter reuse: Connect the terminated component adapter (TAA, refer to PSS 31H-2W4) directly to the original FBM37 wiring without rewiring.

Software adaptation:

Should be paired with Foxboro Evo control software v8. x+or Control Core Services v9.0+, supporting AOUTR redundant function block configuration;

The failure safety parameters need to be pre-set in the software (such as a fallback current of 0mA and a fault delay time) to ensure that the actuator is in a safe state in case of a fault.