Mitsubishi Electric MELSEC FX-2DA User Manual page 6

(1) Channel Selection
Switching between voltage and current output modes. The value of BFM #0 switches the analog output
between voltage and current on channels CH1 and CH2. It takes the form of a 2-character HEX number.
The least significant character controls CH1 and the other controls CH2.
Control of each O HEX character of
:
HOO
:
O=0 Voltage output (-10V to +10V)
Example : H10
(2) Last data reset
If the programmable controller is changed to the STOP state, the FX-2DA will continue to output the last
value. To reset the output to the offset value, set the HEX characters of BFM #5 to one of the appropriate
settings below:
H01 : CH2=Hold, CH1=Reset
H10 : CH2=Reset, CH1=Hold
H11 : CH2=Reset, CH1=Reset
Both channels are held when BFM #5 = H00.
(3) Digital to Analog conversion speed change
By writing 0 or 1 into BFM #7 of the FX-2DA, the speed at which D-A conversion is performed can be
changed. However the following 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
(a)
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 settings have
been corrupted.
(b)
If (b1, b0) of BFM #21 is set to (1, 0), gain and offset adjustments are prohibited. This is to prevent
inadvertent misuse by the operator. To adjust the gain and offset, (b1, b0) of BFM #21 must have
the values (0, 1). The default is set at (0, 1).
(c)
Each time a TO instruction is used to send data to BFM #22 (gain/offset setting command), the
designated gain and offsets of each channel (G2 O2 G1 O1) are adjusted with the values in
BFM #23 and #24. This action causes the adjustments to be written to internal non-volatile EEPROM
memory. Limit this action to as little as possible to preserve the life of the EEPROM memory.
Gain and offset values in BFM #23 #24 are set in units of mV or µA. Due to the resolution of the unit,
(d)
the actual response will be in steps of 5mV or 20µA.
CH1 : Voltage output
:
O=1 Current output (+4mA to +20mA)
CH2 Current output :