Siemens M7-400, S7-400 Status After Switching On, Individual Start of an ADC Channel

Interface Submodules
13-49
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Table 13-42 Meaning of the Control Bits in the Analog Input Function (IF 961-AIO)
Offset
Address D15 Writing D0 Remark
08HA
C
I
N
T0 0 0 0 0 0 0 0 0 0 0 ta ta ta Control register 1
0AH0000000000000 ADC
channel no. Control register 2
0CH000000000000000S
CStatus register ADC
0EHxxxxxxxxxxxxxxxxAcknowledge
interrupt
x = any
ta = 000
ta = 001
ta = 010
ta = 011
ta = 100
AC = 1
INT = 1
ADC channel no.
ADC = 001
ADC = 010
ADC = 011
ADC = 100
SC = 1
5.7 ms cycle time of the automatic conversion function
2.8 ms
1.3 ms
600 µs
185 µs
Automatic conversion of all ADC channels active
Generation of an interrupt after end of cycle
Number of the selected ADC channel:
channel 0
channel 1
channel 2
channel 3
Start of analog-digital conversion, (SC = Start of conversion in the case of individual
encoding)
Status After Switching On
Control register 1: AC = 0, INT = 0, ta = 0 ⇒ 5.7 ms
Control register 2: ADC = 001 ⇒ ADC channel no. = 0
Status register ADC: SC = 0
Individual Start of an ADC Channel
Below are listed the steps required for individual encoding in the case of an ADC
channel:
1. Select the ADC input channel by writing the channel number into control register
2 (offset address “0AH”).
2. Start the ADC conversion by setting the SC bit in the status register ADC to “1”
(offset address “0CH”).
3. Read bit “EOC” in the status register ADC at offset address (0CH) and wait until
EOC = 1.
4. Read the analog value at the relevant address (offset addresses “00H” to “06H”).