MFM / MFC RS-232 Data Communication
24Pages

Specification MFM / MFC RS-232 Data Communication Introduction Axetris offers Mass Flow Meter (MFM) and Controller (MFC) modules, as well as standalone Mass Flow Meters and Controllers. All products feature both analog and digital interface input / output capabilities. Therefore Axetris is able to deliver exactly the required device interface that fits the communication system of each customer application. The goal of this document is to describe in detail all the RS-232 communication features, allowing the customer to quickly connect multiple devices with a single bus wire to their command unit system, establishing a safe and reliable communication. For RS-485 refer to the document MFM / MFC RS-485 Data Communication. Mass Flow Meters / Controllers with RS-232 interface Mass Flow Meter OEM Modules Mass Flow Controller OEM Modules MFM 21XX MFC 21XX Mass Flow Meter Mass Flow Controller Standalone

General Description Transmission errors

Abbreviations, Terms and Definitions Mass Flow Meter Most Significant Bit / Least Significant Bit Mass Flow Controller Read / Read and Write Serial bus standard protocol according to EIA-232 Percent of Full Scale Serial bus standard protocol with TTL level Standard cubic centimetre per minute at reference conditions of 1013 mbar absolute pressure and 0°C temperature. Serial bus standard protocol according to EIA-485 for digital multipoint system communication User defined standard cubic centimetre per minute at reference conditions of 1013 mbar absolute pressure and 0°C temperature. (Term...

Depending on the device type, a meter or a controller, module or standalone, the communication interface features are summarized for the customer mode in Table 1. Analog input Digital input Gas flow Temperature Gas calibration info. Offset zeroing Channel selection2 Gas flow Temperature Gas calibration info. Offset zeroing Channel selection Gas flow Temperature Gas calibration info. Offset zeroing Channel selection Set point 0…5 V Valve override Gas flow Temperature Gas calibration info. PID Controller Output Set point Valve override Offset zeroing Channel selection Gas flow Temperature Gas...

Gas flow meter (Analog/Digital) Gas flow Out Data & command (Digital I/O) EEPROM Parameters Calibration Data Sensor Chip Heater regulation Figure 1 Block diagram of the MFM 2100 and MFM 2200 series of mass flow meter PID_out (Analog/Digital) Set point (Analog/Digital) Valve override (Analog/Digital) Data & command (Digital I/O) uP T Compensation Linearization EEPROM Parameters Calibration Data Valve Driver Sensor Chip Gas flow meter (Analog/Digital) Heater regulation Figure 2 Block diagram of the MFC 2100 and MFC 2200 series of mass flow controller

Power Power Digital In Digital Out Analog Analog Out Analog Out Analog In Analog In + 12 V / + 10% GND (Power) RxD_TTL TxD_TTL GND (Analog) PID_OUT (MFM 2021) Flow value, 0…5V Flow Set-point (MFM 2021) Valve Override (MFM 2021) Power Power Digital In Digital Out Analog Analog Out nc nc + 24 V / + 10% GND (Power) RxD TxD GND (Analog) Flow value, 0…5 V I/O Type Power Power Digital In Digital Out Analog Analog Out Analog Out Analog In Analog In Description + 24 V / + 10% GND (Power) RxD_TTL TxD_TTL GND (Analog) PID_OUT, 0…5 V Flow value, 0…5 V Flow Set-point, 0…5 V Valve Override, 0…5 V I/O...

3 Pin assignment for standalone types 3.1 D-SUB connector – 9 pins (standard) Figure 3 Top view D-SUB 9 poles connector Power Power Digital In Digital Out nc Analog GND Analog Out Power Power Digital In Digital Out nc Analog GND Analog Out GND Flow value, 0…5V Flow Set-point (MFC), 0…5V Valve Override (MFC), 0V close / 5V open GND Flow value, 4…20 mA Flow Set-point (MFC), 4…2mA Valve Override (MFC), 0V close / 5V open Table 3 Pin assignment for D-SUB 9 connector

Device input / output configuration There is no default configuration setup. Due to the many possibilities that are available, the devices are delivered with features which correspond to the customer requirements. Analog input / output is either of voltage type (0…5 V) or current type (4…20 mA). The digital input / output is RS-232. RS-485 is also available (RS-485 Half Duplex MFM 2x40, MFC 2x42 ; RS-485 Full Duplex MFM 2x50, MFC 2x52, see document “MFM / MFC RS-485 Data Communication”). The type of the analog input / output, voltage or current, is set by the manufacturer at the factory...

the valve override command is present to permit immediate shut-off or purge position of the external valve (0 V input – 0 V PID output 100 % close / 5 V input – 5 V PID output 100 % open). This analog valve override command is prior to any other command (analog or digital input). The valve override command is also possible digitally. For the set point, a cut off limit at 1 % F.S. is available on request and is factory settable only. Besides the MFM 2020 communication capabilities (see list above), the MFM 2021 digital communication in customer mode offers: Read Data: - Set point - PID_out -...

The MFC 2022 and MFC 2222 are small compact gas flow controller modules including an advanced internal PID controller with a fast acting solenoid valve. Its main purpose is to be integrated into an OEM system. According to the needs of the customer, the data output can be read in analog (voltage or digital modes using RS-232 TTL (MFC 2022) or RS-232 EIA (MFC 2222). Analog voltage input / output is selected as default input when not specified otherwise during ordering. The preferred way to communicate with the device, analog or digital, can be set later at any time with the corresponding...

The MFM 2120 is a standalone meter. Its purpose is to be a ready-to-use gas flow meter with standard gas fittings. According to the needs of the customer, the data output can be read in analog (voltage or current) or digital using RS-232 (EIA 232) with direct connection to the PC. Analog voltage or analog current input / output is selected as default at the factory level when ordering. The way the customer wants to communicate with the device, analog or digital, can be set later at any time with the corresponding digital command. This configuration is stored in EEPROM making the device...