EL-PRESS Metal Sealed P-702CM (P1-control)

Metal-Sealed Back Pressure Controller

  • Back pressure control (controls upstream pressure "P1")
  • Patented metal-to-metal seal construction ensures long-term leak tightness (to atmosphere)
  • High surface quality of wetted parts
  • Cleanroom assembled
  • For absolute or gauge pressure
  • High accuracy and repeatability
  • Well proven, compact thru-flow design
  • Compact design with on-board PID controller and direct acting control valve
  • Analog, RS232 and fieldbus communication
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EL-PRESS Metal SealedP-702CM (P1-control)

Metal-Sealed Back Pressure Controllers

Bronkhorst® model P-702CM Back Pressure Transducers (EPCs) are designed especially to meet the requirements of the semicon market as well as other high purity gas applications. The instruments feature high surface quality and are of modular construction with metal-to-metal seals that ensure long-term leak tightness. The P-702CM is suited for precise measurement and control of pressure ranges between 20…100 mbar and 12,8…64 bar absolute or 4,2...21 bar gauge. The EPC has a well-proven compact thru-flow design and includes a diaphragm type piezo-resistive pressure sensor, a microprocessor based pc-board with signal and fieldbus conversion and a PID controller for pressure control by means of integrated control valve.

In addition to the standard RS232 output the instruments also offer analog I/O. As an option, an on-board interface can be mounted to provide CANopen®, DeviceNet™, EtherCAT®, PROFIBUS DP, PROFINET, Modbus RTU, ASCII or TCP/IP, EtherNet/IP, POWERLINK or FLOW-BUS protocols

Technical specifications

Measurement / control system
Absolute pressure sensorsCode: 350A - Ranges (FS): 100 ... 350 mbara - P-max: 1,0 bara - Burst pressure: 1,4 bara
Code: 1K1A - Ranges (FS): 0,35 ... 1,1 bara - P-max: 3,1 bara - Burst pressure: 4,2 bara
Code: 6K0A - Ranges (FS): 1,1 ... 6 bara - P-max: 10,5 bara - Burst pressure: 14 bara
Code: 21KA - Ranges (FS): 6 ... 21 bara - P-max: 62 bara - Burst pressure: 84 bara
Code: 64KA - Ranges (FS): 21 ... 64 bara - P-max: 100 bara - Burst pressure: n.a.
Relative pressure sensorsCode: 350R - Ranges (FS): 100 ... 350 mbarg - P-max: 1,0 barg - Burst pressure: 1,4 barg
Code: 1k1R - Ranges (FS): 0,35 ... 1,1 barg - P-max: 3,1 barg - Burst pressure: 4,2 barg
Code: 6K0R - Ranges (FS): 1,1 ... 6 barg - P-max: 10,5 barg - Burst pressure: 14 barg
Code: 21KR - Ranges (FS): 6 ... 21 barg - P-max: 62 barg - Burst pressure: 84 barg
Accuracy (incl. linearity and hysteresis)± 0,5 % FS
Repeatability< 0,1 % RD
Pressure rangeabilitymeasurement: 1 : 50 (2…100%)
control: 1 : 5 (with flow range 1 : 50)
Control stability≤ ± 0,05 % FS (typical for 1 slm N2 at specified process volume)
Operating temperature-10 … +50 °C
up to +70°C on request
Temperature sensitivity0,1% FS/°C
Max. Kv-value6,6 x 10-2
Leak integrity, outboard< 2 x 10-11 Pa.m3/s He
Leak-by through closed valve< 10-5 Pa.m3/s He
Attitude sensitivitymay be mounted in any position
Warm-up timenegligible
Mechanical parts
Material (wetted parts)stainless steel 316L or comparable
Process connections1/4" face seal couplings
Sealsouter seals: metal-to-metal (no O-rings);
valve seat: Kalrez® (FFKM); option: Viton®
Weight0,7 kg
Ingress protectionIP40
Electrical properties
Power supply+15 … 24 Vdc
Max. power consumption
15 V
24 V
at voltage I/O
290 mA
200 mA
at current I/O
320 mA
215 mA
extra for fieldbus
<75 mA
<50 mA
Analog output0…5 (10) Vdc or 0 (4)…20 mA (sourcing output)
Digital communicationstandard: RS232;
options: CANopen®, DeviceNet™, EtherCAT®, PROFIBUS DP, PROFINET, Modbus RTU, ASCII or TCP/IP, EtherNet/IP, POWERLINK or FLOW-BUS
Electrical connection
Analog/RS2329-pin D-connector (male);
PROFIBUS DPbus: 9-pin D-connector (female);
power: 9-pin D-connector (male);
CANopen® / DeviceNet™5-pin M12-connector (male);
FLOW-BUS/Modbus-RTU/ASCIIRJ45 modular jack
Modbus TCP / EtherNet/IP / POWERLINK2 x RJ45 modular jack (in/out);
EtherCAT®/ PROFINET2 x RJ45 modular jack (in/out);
Control valve options
External actuator options to be connected to the controller
Certification for hazardous areas
Approvals / certificates

Technical specifications subject to change without notice.

Note: The measuring cell of the pressure sensor is separated from the external pressure by a thin, sensitive stainless steel diaphragm, and the sealed off cavity between diaphragm and cell is filled with oil. Since the standard oil filling is flammable, Bronkhorst advises to take precautions when oxygen or any other explosive fluid is used.

For dimensional drawings and hook-up diagrams please visit the product page on our website


Metal Sealed Mass Flow and Pressure brochure
Quick Start Guide EL-PRESS Metal Sealed
Hook-up diagrams
Analog IO - RS232
Optional Bus and IO Configurations
Dimensional drawing