Rosemount 2081 pH, Инструкция по эксплуатации

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20
SECTION 6.0 KEYBOARD SECURITY
GENERAL. This feature allows the user to disable the
dual push buttons on the transmitter, preventing acci-
dental or unauthorized changes to the calibration and
configuration via the transmitter. HART communication
is not effected by this change. Perform the following
steps to disable the push buttons:
CAUTION
The circuit board is electrostatically sensi-
tive. Be sure to observe handling pre-
cautions for static-sensitive components.
1. Remove the display side cover.
2. On the CPU board ( Figure 6-1 , Model 2081 pH
jumper settings), move JP4 to one post only.
NOTE
For easy access, the electronics assembly
may be removed by pulling the assembly
straight out.
3. Replace the display side cover.
CAUTION
A minimum of seven cover threads must
be engaged in order for the transmitter to
meet explosion-proof requirements.
Replace the jumper to enable push button operation.
FIGURE 6-1. Model 2081 pH Jumper Settings
JP3
JP4
JP1
JP1: Selects for 50 or 60 Hz operating environment.
(Allows better noise reduction for A/D convertor). In a
60Hz environment, no shorting bar is used.
JP4: The two push buttons will have no
effect if this shorting bar is removed.
JP3: Selects fault condition current loop
output level (Hi=21.75/Lo=3.80mA)
To fault Hi, no shorting
bar should be installed.
U2
U3
U1
DWG. NO. REV.
233050-00
MODEL 2081 pH SECTION 6.0
KEYBOARD SECURITY