Mitsubishi Electric MELSEC FX-2DA User Manual Download Page 5

BFM

  *# 0

  *# 1

  *# 2

# 3-# 4

  *# 5

   # 6

# 8-#19

In BFM's (buffer memory) with an “ ”, data
can be written from the programmable cont-
roller using the TO command.

These BFM's should always be given when the
programmable controller goes from STOP to
RUN. Buffer memory (BFM's) are reset to their
default settings upon power on.

BFM

  *#20

#25-#28

   #29

   #30

   #31

  *#21

  *#22

  *#23

  *#24

The buffer memory also handles information
used to adjust the gain and offsets of the FX-
2DA unit. Status of the unit such as errors
are also available.

From BFM #29 and #30, data can be read
via the FROM command.

Offset value : the actual output value when

the digital input is 0.

Gain value :   the actual output value when

the digital input is +1000.

contents

channel  Initialization (Default = H00)

channel 1

channel 2

Reserved

Last data reset (Default = 0)

Reserved

selection of A-D

conversion speed

see note

Reserved

Gain/offset adjust prohibit

Initial value (0,1)

Offset/gain

setting command

G 2     O 2     G 1     O 1

Pro-

hibit

Permit

b 3     b 2     b 1     b 0

Reset all to default    default value: 0

Offset data (in mV or 

µ

A units)

default value: 0

Gain data (in mV or 

µ

A units)

default value: 5,000

Reserved

Error status (See next page)

Identification code K3010 (See next page)

Reserved

  *# 7

When set to 0, normal

speed is selected 18ms

When set to 1, high

speed is selected 3.5ms

3.4 Allocation of buffer memories (BFM)

Summary of Contents for MELSEC FX-2DA

Page 1: ...ion The FX 2DA has a maximum resolution of 12 bits The selection of voltage or current based input output is by user wiring Analog ranges of 10 to 10V resolution 5mV and or 4 to 20mA resolution 20µA maybe selected FX programmable controllers versions 2 0 or later those with serial number 13XXXX or larger are required as these units have the TO FROM applied instructions in their instruction set Dat...

Page 2: ...aution a The same output channel cannot drive current and voltage output loads at the same time b Shorting the voltage output terminals may da mage the unit FX 2DA special function block V V I I 2 Groove for 35mm 1 38 wide DIN rail 2 5 5mm 0 22 hole M3 5 0 14 terminal screws Wiring 2 2 Apply 1 point grounding at the load side of the output cable class 3 grounding 100 Ω or less If electrical noise ...

Page 3: ...rcuits Item Item Max convertible output range Digital input Overall accuracy Conversion speed Resolution Current output 5mV 10V full scale 1 2000 DC 4mA to 20mA external load 500 Ω or less Current 0 to 1000 1 full scale 20mA range 20µA 20mA full scale 1 1000 Factory Presets Load 10kΩ Ω Ω Ω Ω voltage Output 250Ω Ω Ω Ω Ω current Output Analog output 2047 10V 5V 5V 10V 2000 1000 2048 10 24V 10 235V D...

Page 4: ...M ON OFF Due to the inevitable timing difference of the DC24V for the analog circuits and other power lines of the base unit the output of the FX 2DA special function block may behave erroneously before settling down to operational conditions in approximately 1sec Therefore ensure that this behavior is taken into account such that the end performance of the system is not degraded example Power swi...

Page 5: ... the actual output value when the digital input is 0 Gain value the actual output value when the digital input is 1000 contents channel Initialization Default H00 channel 1 channel 2 Reserved Last data reset Default 0 Reserved selection of A D conversion speed see note Reserved Gain offset adjust prohibit Initial value 0 1 Offset gain setting command G 2 O 2 G 1 O 1 Pro hibit Permit b 3 b 2 b 1 b ...

Page 6: ... points should be noted Note The conversion speed does not depend on the number of channels being used On power up the FX 2DA is set for normal speed conversion and BFM 7 contains 0 4 Adjusting Gain and Offset Values When BFM 20 is set to K1 all settings in the buffer memory are reset to their default settings This allows the buffer memory settings to be set from the beginning again when many sett...

Page 7: ...FF Hardware normal READY mode Permit b1 b0 of BFM 21 is set at 1 0 Values of BFM 0 5 21 23 and 24 are stored in EEPROM memory of the FX 2DA BFM 23 and BFM 24 are only copied when the gain offset setting command BFM 22 is used Also BFM 20 causes resetting of the EEPROM memory The EEPROM has a life of about 10 000 cycles changes so do not use programs which frequently change these BFMs Because of th...

Page 8: ...r up the system the FX base unit can be in either RUN or STOP mode Offset and gain can be used independently or together Reasonable offset ranges are 5V to 5V or 20mA to 20mA and gain offset difference 1V to 15V or 4mA to 32mA Gain and offset can be adjusted by software in the FX base unit see program example 2 or by the switches on the FX 2DA with the aid of a voltmeter ammeter Bit device s b0 b1...

Page 9: ...is is compared to check the block is an FX 2DA if OK M1 is turned ON These two program steps are not strictly needed to perform an analog output They are however a useful check and are recommended as good practice The analog output channels CH1 CH2 are set up by writing H10 to BFM 0 of the FX 2DA Output data normal The operational status of the FX 2DA is read from BFM 29 and output as bit devices ...

Page 10: ...f the FX 2DA connected as block No 1 Example Adjusting gain offset via software settings X010 M0 T0 T1 K1 K1 H10 K1 K0 K21 K1 K1 K1 K0 K22 K1 TO TO P TO P TO P TO P K1 K1 K1 K1 K23 K24 K22 K21 K0 K20000 HC RST K2 K1 K1 K1 M0 K1 Adjustment start H10 BFM 0 initialize input channels In the program shown at left the programmable controller should be in RUN status and MODE switch of the FX 2DA in the R...

Page 11: ...overload on either the 5V or 24V power source remember the loading on the FX base unit or a powered extension unit varies according to the number of extension blocks or special function blocks connected 6 Pit the main processing unit into RUN 6 2 Error checking Check the status of the POWER LED Lit The extension cable is properly connected Otherwise Check the connection of the extension cable Chec...

Page 12: ... Electric distributor Under no circumstances will Mitsubishi Electric be liable or responsible for any consequential damage that may arise as a result of the installation or use of this equipment All examples and diagrams shown in this manual are intended only as an aid to understanding the text not to guarantee operation Mitsubishi Electric will accept no responsibility for actual use of the prod...

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