106 • I/O modules
Counter modules 750-404, /000-XXX
Modular I/O System
ETHERNET TCP/IP
An example:
Setting counter to a value of 100 and counting up
First of all the counter reading is set to 100 by "Setting counter", i. e. to the
hexadecimal value: 0x64.
1.
Enter the counter reading in the output data.
The data bytes D0 to D3 of the output data then read as follows:
D3
D2
D1
D0
0x00
0x00
0x00
0x64
2.
Validate the counter reading in the control byte with bit 5 (setting counter) to
have it adopted as an output value. The control byte has the following bits:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
X
1
X
X
X
X
X
3.
Wait for the feedback from the counter module in the status byte, bit 5
(counter set). The status byte has the following bits:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
X
X
1
X
X
X
X
X
4.
Set bit 5 (setting counter) in the control byte in order to finish the Hand-
shake. The bits in the control byte read as follows:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
X
0
X
X
X
X
X
5.
The set counter reading then appears in the input data with the following
data bytes D0 to D3:
D3
D2
D1
D0
0x00
0x00
0x00
0x64
Counter counting up:
Attention
For counting up, 24 V must be applied to input U/D.
6.
Wait for the first and further count pulses.
During counting, the data bytes D0 to D3 of the input data appear as follows:
D3
D2
D1
D0
Remark
0x00
0x00
0x00
0x64
no count pulse received
0x00
0x00
0x00
0x65
1st count pulse received
0x00
0x00
0x00
0x66
2nd count pulse received
........
........
........
........
0xFF
0xFF
0xFF
0xFF
Max. counter reading reached
0x00
0x00
0x00
0x00
the next count pulse causes a number overflow
0x00
0x00
0x00
0x01
One further count pulse received
........
........
........
........
Attention
"X" is used if the value at this position is without any significance.