INSTALLATION AND OPERATING INSTRUCTIONS
SKF Multilog On-line System IMx-8/IMx-8Plus
26 (63)
SKF Multilog On-line System IMx-8/IMx-8Plus
User Manual
Revision E
Figure 12
250-ohm resistor for a 4-20 mA signal
Note: All ground terminals (G1
–
G8) of the analogue inputs are connected to each
other, to secure a common ground level. As all channels are referenced to
chassis/enclosure ground, take care to avoid ground loops!
2.5.10 Connecting tacho/speed signals (D1 to D2)
Connecting a tacho signal to the IMx allows an assessment of rotational speed of the
monitored shaft and the operational state of the machine or train. Often a multi-event
target is used as this enables a faster update of speed, but if needed, both vibration
phase and speed data can be obtained by using a single event per rev target.
The tacho sensor will normally be mounted to detect the changing presence of a
target. For example, a single event per rev target can often be arranged using either,
an existing: key or a key-way.
A sensor with suitable sensing range must be selected and gapped appropriately to
accommodate any movement between sensor and target, that might occur. The
IMx-8/IMx-8Plus support two-wire, three-wire PNP and pulse sources*.
*The digital input and trigger characteristics are specified in
. Suitable pulse
sources include, for example, a TTL like signal of 0 to 5 V and 50% duty cycle or
other positive pulse sources up to 24 V. To ensure reliable triggering when using
sensor/target systems that tend to produce shorter duration pulses with slower rise
times, ensure that the pulse signal available at the IMx input comfortably crosses the
trigger threshold and aim for pulse heights of 12 to 24 V, where possible.
The digital input connectors are located on the top end cap of the IMx, refer
or
For each tacho input, 3-terminals are available:
•
P
Power for the sensor, refer
•
D
Digital signal in
•
G
Common or return connection
