Brooks Instrument 5851S Smart Mass Flow Controller —
About this part
BD1DA1FB2AA1B2 identifies a configured Brooks Instrument 5851S Smart thermal mass flow controller. Its ordering code specifies 3/8-inch tube-compression fittings, Viton seals and valve seat, a normally closed valve, RS-232 communication at 19,200 baud, digital setpoint control with digital and 4–20 mA flow output, standard response, one standard calibration, 24 VDC power, and ATEX Zone 2 classification. The exact calibration gas and full-scale value are calibration-record attributes and are not encoded in this identifier
Configurations vary. Verify the exact unit before choosing a replacement.
Application classSemiconductor/high-purity gas delivery
CategoryFlow Control
Specifications
Identification
Manufacturer
Brooks Instrument
Series
5800-S Smart Series
Base model
5851S
Complete model code
5851S/BD1DA1FB2AA1B2
Product
Instrument type
Smart thermal mass flow controller for gases
Flow
Full-scale selection band
20–100 ln/min nitrogen-equivalent; the exact selected full-scale value is not encoded
Reference conditions
0 °C and 1013.25 mbar
Standard accuracy
±0.7% of rate plus ±0.2% of full scale at calibration conditions
Repeatability
±0.25% of rate
Rangeability
50:1 within specified accuracy
Controllability
100:1 total operating range
Long-term stability
Less than ±0.5% of rate per year
Configured Process Interface
Process connections
3/8-inch tube-compression fittings
O-ring and valve-seat material
Viton fluoroelastomer
Configured Valve
Valve type
Normally closed
Configured Electrical Interface
Setpoint input
Digital communication
Flow outputs
Digital communication and 4–20 mA analog output
Serial interface
RS-232 at 19,200 baud
Interconnection cable
No cable supplied by the ordering-code selection
Power input
+24 VDC
Electrical
Normal power consumption
+24 VDC ±10% at 140 mA
Power consumption with valve override active
+24 VDC at 370 mA
Connector
15-pin male D-type connector with gold-plated contacts
Alarm output
NPN TTL open collector; 30 VDC and 25 mA maximum
Configured Performance
Response selection
Standard response; approximately 1-second nominal settling and flow-output response
Configured Calibration
Calibration selection
One standard calibration included; gas and exact full-scale value are not encoded
Configured Certification
Area classification
ATEX Zone 2, KEMA 03ATEX1433 X, II 3 G EEx nA II T4
Operating Limits
Ambient and process-gas temperature
0–70 °C
5851S pressure rating
100 bar maximum
Performance
External leak integrity
1 × 10^-9 mbar·L/s helium
Warm-up
Less than 10 minutes for 1% full-scale accuracy; 45 minutes for performance within specifications
Dimensions
Connection dimension A
148 mm without filters or 184 mm with filters for the configured 3/8-inch tube-compression connections
What Does BD1DA1FB2AA1B2 Mean?
Brooks ordering literature divides the identifier into the following configured selections.
Segment
Field
Interpretation
BD
Base model and flow band
5851S mass flow controller; selectable full scale from 20 to 100 ln/min nitrogen-equivalent
1D
Mechanical connection
3/8-inch tube-compression fittings
A
O-ring and valve-seat material
Viton fluoroelastomer
1
Valve type
Normally closed valve for the 5850S/5851S series
F
Electrical input/output
Digital communication input; digital communication and 4–20 mA output
B2
Communication and baud rate
RS-232 at 19,200 baud
A
Interconnection cable
No cable
A
Enhancement
Standard-response configuration
1
Calibration
One standard calibration included
B
Power input
+24 VDC standard selection
2
Area classification
Certified for use in ATEX Zone 2
Configured Connector Signals
Signals relevant to the configured 24 VDC, RS-232, 4–20 mA interface are listed below.
Pin
Signal
Function
3
TTL open-collector alarm
NPN alarm output, 30 VDC and 25 mA maximum
4
4–20 mA flow output
Configured analog flow signal
5
+24 VDC supply
Positive power input
9
Power-supply common
Supply and serial common reference
10
Flow-output common
Analog flow-signal return
12
Valve override
Floating for normal control; ≥5 VDC commands open and ≤0 VDC commands closed
14
RS-232 RxD
Serial receive
15
RS-232 TxD
Serial transmit
Calibration-Specific Data
The ordering code confirms a standard calibration but does not encode the calibration gas or exact full-scale flow value. These values must be taken from the instrument’s calibration label or certificate.
Installation and Safety Notes
The integral control valve provides precision regulation and is not a positive shutoff valve; install a separate downstream shutoff valve where positive isolation is required.
Use clean gas and maintain the standard inlet filter to protect the sensor and control valve.
For operation above 10 bar, horizontal mounting is preferred to reduce zero-flow thermal-siphon effects.
The Zone 2 certification requires installation in a suitable enclosure providing at least IP54 protection.
