2-33
2
is the first available nibble. If 2 bytes were used in step 4, then MSN-
4 becomes the next available nibble.
i.e. for an output string of "1234" starting with MSN-4, the "0001" code
will appear on lines CH24-CH21.
Assign the signals to the proper bit weights so that the numbers come out
correctly for the external device. For 8-bit data use the binary bit
numbers where bit 0 is the LSB. Record the device signal names and pin
numbers in Table 2-9. Leave the unused data lines open. Record the
bytes used and signal polarity in Table 2-10.
6. If any data will be transferred with Byte commands, their signals should
be connected now. Assign the signals to the remaining data lines. All
signals on a byte will be all inputs or all outputs but they can have
individual bit polarities. Record the device signal names and pin
numbers in Table 2-9. Record each byte's polarity in Table 2-10.
7. If the Output Drivers are being used, they should be assigned now. Use
separate wires to connect the Driver Voltage pin to the external power
supply voltage and the Driver Return pin to the external power supply
return. Record the signal names and pin numbers in Table 2-9.
8. If the Analog Outputs are being used, they should be assigned now.
Connect the D/A Ch Ground to the signal ground in the circuits being
controlled. For best results, shield the lines or use twisted pairs. Pin 48
is the common ground pin. Record the signal names and pin numbers
in Table 2-9. Record scale factors and offsets in Table 2-10.
9. If the Analog Inputs are being used, they should be assigned now. If the
inputs have transients that exceed
±
12 Vdc, use a varistor to limit the
transients before connecting the signals to the unit. Connect the A/D Ch
Ground to the source of the analog signals. Use shielded leads and filter
the inputs as necessary to reduce noise pickup. Record the signal names
and pin numbers in Table 2-9. Record scale factors and offsets in Table
2-10.
10. If the Thermocouple Inputs are being used, they should be assigned
now. Use Type J thermocouples. Assign the FE (-) lead to the TC-
inputs. (Note some thermocouples may have red and white lead
