Setting 4 To 20 Ma Interface Behavior During 1900/27 Monitor Bypass - GE Bently Nevada 1900/27 Operation And Maintenance Manual

1900/27 Vibration Monitor Operation and Maintenance Manual
2.2.3 Setting 4 to 20 mA Interface Behavior During 1900/27 Monitor
Bypass
With the BYPASS Mode jumper installed the 4 to 20 mA circuit responds to a relay
bypass condition at the monitor by sending a NOT OK signal (less than 3 mA) to
the plant computer. Even though the relays are in BYPASS, the monitor remains
OK and continues to monitor vibration. The 4 to 20 mA circuit is unable to
continue sending a vibration signal when this jumper is in, but visibility of a bypass
condition is maintained at the plant computer.
With the BYPASS Mode jumper removed, bypassing the relays does not affect the
4 to 20 mA interface.
Table 2.3 shows how to use the Bypass Mode jumper to control how the 4 to 20
mA interface responds when the monitor is bypassed.
TABLE 2.3: Bypass Mode Jumper Settings
Bypass
mode
jumper
(W4)
installed*
removed
* Factory default setting
To determine realistic setpoint values for a machine, we recommend that you
collect data for a few weeks with the relays disabled and the bypass jumper
removed. Use this configuration only long enough to collect enough data to
determine where to adjust the Alert and Danger setpoints. After you establish
realistic setpoints, install the bypass mode jumper and return to the normal
monitoring mode by placing the relay mode switch in the NORMAL positrion.
8
Response of the 4 to 20 mA interface when
the monitor's relays are bypassed
Flag the point as Not
OK
yes
no
Transmit vibration
signal when relays
are bypassed
no
yes