scaling problem with controllogix

J

Thread Starter

Jerry Overton

How do I set the scaling for a 1771fe modular from controllogix thur dh+ to asb modular. Is there a easy way to understand the word format.I read the manual for btr and btw but there is something that I must be missing, al that I need to do is the scale the input for 4-20 mA to display 0- 2000 GPM but what I am getting is 0-20mA scaling.Is there some way to do this thur vba and excel 2000. Thanks Jerry
 
K

Kent L. Gerhardt

Moving data from 1771-IFE to ControlLogix in desired format

There are 2 ways to get the 0-2000 GPM scaling over 4-20 mA. The first is to leave the 1771-IFE module reporting over 0-20 mA and change your scaling to -500 to 2000 GPM. The second method is to reconfigure the channels on the input module to read over 4-20 mA. This makes it more difficult to detect a blown transmitter circuit fuse (or other open) as the module will report 4 mA for any reading of 0 - 3.999 mA. To do this look again at the IFE manual, configuration chapter. The excerpt below shows one how to do this.

> From Allen Bradley Manual 1771-6.5.90:
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You can configure the module to operate with any of five voltage or three current ranges. You can select individual channel ranges using the designated words of the write block transfer instruction (Table 4.A). Use BTW word 1 for range selection of channels 1 through 8, and BTW word 2
for channels 9 through 16. Two bits are allocated for each channel. For example, for channel 1, set word 1 bits 00-01 as shown in Table 4.A.

Table 4.A
Input Range Selection Bits
Bit 01 Bit 00 Voltage or current input
0 0 ... 1 to 5 V DC, 4 to 20 mA
0 1 ... 0 to 5 V DC, 0 to 20 mA
1 0 ... 5 to +5 V DC, 20 to +20 mA
1 1 ... 10 to +10 V DC2, 0 to 10 V DC
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Kent L. Gerhardt
Gerhardt & Associates
P.O. Box 2062, Hammond, LA 70404 USA
voice: 985.542.1963
fax: 985.345.5475
cell: 985.634.8804
 
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