Westermo RM-505U-2-E - Manual (Page 11)

User Manual
MAN_505_1.7.DOC Page 11
If the pulse input message is sent to a host device, it is important to note that the count value
transmitted is an absolute value. The only time that it resets is when the 16-bit accumulator "rolls
over" (exceeds 65 535).
Overview:
•
Pulse inputs are counted.
•
Pulse count is transmitted when the count has increased by the sensitivity amount since the last
transmission.
•
Update message if the input value has not been transmitted within the update time (10 seconds -
5 days).
•
After each transmission, another transmission for that input is disabled for the paralysis time (0 –
127.5 sec).
Two pulse inputs may be configured to control one count value, for use with quadrature and
incremental shaft encoders. A shaft encoder is a transducer that measures level or displacement,
and has two pulse signals to indicate change of level and direction of change.
Both pulse inputs are read at the same time.
If using an incremental encoder, the count is the value of Pulse Input 1. This pulse input value should
be used to send the true pulse count from a incremental encoder.
If using a quadrature encoder, the count is the value of Pulse Input 2. This pulse input value should
be used to send the true pulse count from a quadrature encoder.
2.3.3 Analogue Inputs
The analogue input uses a “sample time” and “warm-up time” configured by the user. The sample
time (1 minute to 20 days) “wakes” the 505U from sleep mode and turns on the analogue loop
supply. The “warm-up time” (0.5 – 127.5 seconds) allows the transducer to reach rated accuracy
before the 505U makes a measurement of the analogue signal.
For example, if the sample time is 30 minutes and the warm-up time is 10 seconds, then every 30
minutes, the 505U will turn on its analogue loop supply and after a further 10 seconds, take a
measurement of the analogue signal. After the measurement is taken, the 505U reverts to sleep
mode. The loop voltage available for a transducer is approx 1.5V less than supply voltage for
externally powered models or 8.5V for battery powered models.
If the sample time is set to zero, then the analogue loop supply will be on continuously and
measurement will be taken based on the warm-up time. If the warm-up time is 1 second, then a
measurement is taken every 1 second.
The same process occurs if an externally powered analogue signal is connected.
The measurements have a resolution of 12 bit, and an overall accuracy of better than 0.1%.