9
Connection
Digital outputs (channels 21–22)
Use the Model 7706 digital outputs to control indicators, fixtures, switches, solenoids, loads, relays, etc.
Figure 9
shows a sim-
plified schematic of the digital output.
Figure 9
Simplified schematic of digital output
Setting the digital output in 8-bit (byte)
To set the digital output, send the decimal equivalent of the binary pattern desired. Keep in mind that on each port, bit 7 is the
most significant bit (MSB) and bit 0 is the least significant bit (LSB). This makes the pin 1 screw terminal of each digital port
(TE2 and TE1) the LSB, and pin 10 the MSB.
NOTES
TE2 is Channel 21 and TE1 is Channel 22.
Pins 5 and 6 on each digital port are ground.
To find the decimal equivalent of the binary pattern, first determine the pattern mapped to the screw terminals on the desired
digital output (refer to the example contained in
Figure 10
). Setting a bit to a logic ‘1’ effectively sets the screw terminal to +5V,
while setting it to a logic ‘0’ sets the screw terminal to 0V. Then, for each screw terminal (or bit position), multiply the binary
value (either a 1 or a 0) by the decimal weight (see
Figure 10
). The sum of the products is the decimal equivalent value of the
binary pattern. This decimal value can be either sent over the bus (as in the example) or by using the front panel of the Model
2700. To send it over the front panel: under the SHIFT->CARD menu, key in the decimal value (138) for the menu item
“DIGOUT1: XXX”. Refer to
Figure 11
for a sample on Channel 22.
Non-isolated
Reference to chassis ground
Bit
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
16
Digital
Output
Channel 21
Channel 22
