(1) Channel Selection
Channel initialization is made by a 4 character HEX number HOOOO in buffer memory BFM #0.
The least significant character controls channel 1 and the 4 character controls channel 4.
Setting of each character is as follows:
O = 0: Preset range (-10V to +10V) O = 2: Preset range (-20mA to +20mA)
O = 1: Preset range (+ 4mA to + 20 mA) O = 3: Channel OFF
Example: H3310
CH1: preset range (-10V to +10V)
CH2: preset range (+ 4mA to +20mA)
CH3, CH4: Channel OFF
(3) Adjusting Gain and Offset Values
When buffer memory BFM #20 is activated by setting it to K1, all settings within the analog special
function block are reset to their default settings. This is a very quick method to erase any undesired
gain and offset adjustments.
If (b1, b0) of BFM #21 is set to (1,0), gain and offset adjustments are prohibited to prevent inadvertent
changes by the operator. In order to adjust the gain and offset values, bits (b1, b0) must be set to
(0,1). The default is (0,1).
Gain and offset values of BFM #23 and #24 are sent to non-volatile memory gain and offset registers
of the specified input channels. Input channels to be adjusted are specified by the appropriate G-O
(gain-offset) bits of BFM #22 Example: If bits G1 and O1 are set to 1, input channel 1 will be
adjusted when BFM #22 is written to by a TO instruction.
Channels can be adjusted individually or together with the same gain and offset values.
Gain and offset values in BFM #23 #24 are in units of mV or
µ
A. Due to the resolution of the unit the
actual response will be in steps of 5mV or 20
µ
A.
(a)
(b)
(c)
(d)
(e)
By writing 0 or 1 into BFM #15 of the FX-4AD, the speed at which A-D conversion is performed can be
changed. However the following points should be noted:
To maintain a high speed conversion rate, use the FROM/TO commands as seldom as possible.
NOTES: When a conversion speed change is made, BFM #1-#4 are set to their default values immediately
after the change.
This is regardless of the values they held originally. Bear this in mind if a speed change will be
made as part of the normal program execution.
(2) Analog to Digital Conversion Speed Change
