BusWork® 965EN Module User’s Manual Modbus TCP/IP mV/TC Input
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Acromag, Inc. Tel:248-295-0880 Fax:248-624-9234 Email:
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There are nine calibration channels for the 965EN-4006, six input channels
plus three temperature references (CJC). There are six calibration channels
for the 965EN-4004, four input channels plus two temperature references
(CJC). Input channels are calibrated differently than temperature reference
channels.
Note that because of equivalent A/D gain selections between some ranges,
Type K and Type N are calibrated at the same time Type J is calibrated, and
Type R and Type S are calibrated at the same time Type T is calibrated.
Also, Type J and the ±1V ranges must be calibrated prior to calibrating the
CJC references.
Method 1
– Calibration Using The Built-In Browser Interface:
1. Make sure that the range that needs calibrating is currently selected.
2. Turn CJC off.
3. Bring up browser interface and select the calibration page.
4. Apply either the Cal LO or Cal HI input signal to the channel to be
calibrated. Calibrate the low endpoint signal first, before the high
endpoint signal.
5. Wait about 10 seconds for the input to settle and be read.
6. Click on the channel number and select either low or high calibration.
7. Click on the “Calibrate” button. The page will refresh and calibration may
continue. Repeat this process for the other endpoint (Cal HI).
8. Repeat steps 4-7 for the other input channels to be calibrated for this
same range.
9. Repeat steps 1-7 until all input ranges have been calibrated. Note that
Type K and Type N are calibrated by calibrating Type J, and type R and
Type S are calibrated by calibrating by calibrating Type T.
Method 2 - Calibration Via The Modbus TCP/IP Interface:
1. Write to the TC Break & CJC Configuration Register to turn CJC OFF
and set the break detection as required by your application.
2. Write to the appropriate Input Range Register to select the input range to
be calibrated for your channel of interest.
3. Write 24106 (5E2AH) into the Calibration Access Register to remove
write protection from the calibration registers.
4. Apply the zero calibration signal (Cal Lo, see table) to the input to be
calibrated and allow the input to settle about 10 seconds.
5. Write a 16-bit value to the Zero Calibration Register with a set bit in the
bit position that corresponds to the channel number to be calibrated (one
channel at a time). If you were calibrating the zero of channel 5, you
would write 0x0020 to the Zero Calibration Register. The module will
replace calibration coefficients immediately, no reset is needed.
6. Apply the full-scale calibration signal (Cal Hi, see table) to the input to be
calibrated and allow the input to settle about 10 seconds.
7. Write a 16-bit value to the Span Calibration Register with a set bit in the
bit position that corresponds to the channel number of the channel to be
calibrated (one channel at a time). For example, if you wanted to
calibrate the span of channel 0, write 0x0001 to the “Span Cal Register”.
8. Repeat steps 4-7 for the other channels as required.
9. Repeat steps 2-8 for the next range as required.
10. When finished calibrating, write 0x0000 to the Calibration Access
Register (Holding register 21) to replace write protection to the
calibration registers and prevent miscalibration.
WEB BROWSER
Calibration Page
Input Calibration
You can choose to use the
web browser calibration page
to accomplish calibration as
described in Method 1 at right
(easiest), or via direct register
access as described in Method
2 below.
