Rockwell Automation 1771-N SERIES High Resolution Analog Module User Manual - Manual (Page 75)

6–7 Module Calibration
Publication 1771ĆUM127B-EN-P - December 2002
Output Channel Calibration
1. Set the appropriate bit in the BTW output calibration mask (word
3); channel 1 is bit 0, channel 2 is bit 01, etc. If calibrating only
one channel, set the appropriate bit. If calibrating the entire
module (all outputs), set all bits (00 through 07).
2. Send a block transfer write to the module with word 1 containing
CAL CLK bit (01) = 1, and HI/LO bit (00) = 0 and all output cal
values = 0.
3. Send a block transfer write to the module with
CAL CLK bit (01) = 0, and HI/LO bit (00) = 0 and all
output cal values = 0.
4. Measure the signal on the channel you are calibrating. Use the
appropriate equation below to calculate the output cal low value
for this channel. Record this value for later use. Do not enter it
into the BTW file at this time.
10V Output
25mA Output
Y = (X x 6000) - 30000
Where: X = meter readingin volts
Y = output cal low/high value
Where: X = meter readingin mA
Y = output cal low/high value
Y = x 60000 - 30000
(X - 0.500)
21.500
50mA Output
Where: X = meter readingin mA
Y = output cal low/high value
Y = x 60000 - 30000
(X - 1.000)
49.000
[
]
]
[
5. Send a block transfer write to the module with word 1 containing
CAL CLK bit (01) = 1, and HI/LO bit (00) = 1 and a ll output cal
values = 0.
6. Send a block transfer write to the module with CAL CLK bit (01)
= 0, and HI/LO bit (00) = 0 and all output cal values = 0.
7. Measure the signal on the channel you are calibrating. Use the
appropriate equation above (step 4) to convert the value to the
output cal high value for this channel.
Record this value for
later use. Do not enter it into the BTW file at this time.