Rockwell Automation 1771-OFE/B Analog Output Module User Manual - Manual (Page 33)

3-7
Publication 1771Ć6.5.30 - November 1998
The largest value that you can enter for a maximum scaling value is
9999. The smallest value you can enter for a minimum scaling value
is -9999 (the minus sign is implemented by setting the appropriate
bit in the configuration word).
Important: The maximum scale value must be larger than the
minimum scale value. If not, block transfers continue
but data is not acknowledged by the module’s
microprocessor. Outputs remain in their last state
before the fault.
Even if you scale fewer than four channels, a full 13-word block
transfer is performed.
When scaling, all scaling information must be entered into the data
table using the same format that the module sends to the data table.
If Module is configured for: Then enter scaling values in:
BCD format BCD
2's complement
Binary
Signed Magnitude Binary
Binary
Important: PLC-2 users should always use BCD format because
the PLC-2 processor performs math functions using
BCD data. The PLC-3, PLC-5 and PLC-5/250 use
integer math, you should use 2”s complement binary for
any data that will be used with math instructions
(including PID and CAR routines). BCD format is
usually reserved for display purposes only.
Figure 3.3
Location of Maximum and Minimum Scaling Values in the Write File
Word Description
1 Channel 1 Data Value
2 Channel 2 Data Value
3 Channel 3 Data Value
4 Channel 4 Data Value
5 Configuration Word
6 Channel 1 Minimum Scaling Value
7 Channel 1 Maximum Scaling Value
8 Channel 2 Minimum Scaling Value
9 Channel 2 Maximum Scaling Value
10 Channel 3 Minimum Scaling Value
11 Channel 3 Maximum Scaling Value
12 Channel 4 Minimum Scaling Value
13 Channel 4 Maximum Scaling Value