Reference Manual
00809-0100-4514, Rev BA
January 2008
5-3
Rosemount 1154
SENSING MODULE
CHECKOUT
NOTE
Numbers in parentheses refer to item numbers in Figure 5-2 on page 5-5.
The sensing module (12) is not field-repairable and must be replaced if
defective. If no defect such as a punctured isolating diaphragm or loss of fill
fluid is observed, check the sensing module in the following manner:
1. Disengage the header assembly board (4) as described in step four
of the electrical housing disassembly procedure on page 5-6. You
need not remove the sensing module from the electrical housing for
checkout.
2. Jump connections 1 and 2 on the header assembly board (see Figure
5-1 on page 5-2).
3. Using a low-voltage ohmmeter, check the resistance between the
jumper wire and the sensing module housing. This resistance should
be greater than 10 MΩ. Remove the jumper wire.
4. Jump connections 3 and 4 on the header assembly board and repeat
step 3 (see Figure 5-1 on page 5-2).
NOTE
The above procedure does not completely test the sensing module. If circuit
board replacement does not correct the abnormal condition and no other
problems are obvious, replace the sensing module.