Westermo RM-505U-K - Manual (Page 10)

505K Radio Telemetry Module User Manual
    ELPRO Technologies Pty Ltd 2008 Page 10
achieved on PI2 provided the divider is set such that the scaled count rate is less than
10KHz (see below).
There is no minimum pulse rate. For PI2, there is a configurable scaling divider (integer 1 –
255). This allows the pulse count to be scaled. If a divider of X is configured, then the pulse
count will increase by 1 for each X input pulses. There is a separate divider for each pulse
input. The divider parameter could be used for the following reasons:
If the pulse count is to be transmitted to a pulse output on a 105U, then the maximum
pulse rate is 100Hz. If the input rate is more than 100Hz, then it can be reduced with the
divider. For example, if the maximum input rate is 300Hz, then the use of a 10 divider
will bring the effective rate down to 30Hz - each output pulse will then represent 10
input pulses.
The divider can be used to scale the pulse count to engineering units. For example, if the
input pulse rate is 7 pulses per m
3
of gas, then a divider of 7 will result in a pulse count
corresponding to the number of m
3
. Note that the divider must be an integer.
The divider could be used to slow down the pulse rate. If the input pulse rate is 5KHz,
then the base 16 bit counter will overflow in approx 13 seconds. If the overflow counter
is not used, then this may be too fast to be processed by HMI software. If a divider of
100 is used, then the counter will take over 20 minutes to overflow.
There is no divider for PI1.
If the pulse count is transmitted to a pulse output on a 105U module, the 105U will compare
the input count to its own output count (the count of output pulses), and will then output
pulses until the two counts are the same. If the pulse counts are transmitted to a 105U-C or
105U-G interface module, then the 105U-C will store the pulse count value in an internal
register.
For pulse rates higher than 10 Hz, the “Fast Pulsed Inputs” option should be selected. This
increases power consumption of the module significantly and is not suitable for a battery
power supply.
Overview:
• Pulse inputs are counted as 2 x 16 bit registers.
• 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 - 7 days).
• After each transmission, another transmission for that input is disabled for the paralysis
time (0 – 127.5 sec).
• PI2 can be scaled by a configurable divider.
The diagnostics functions of the 505K allow the user to manually set the counter values to any
value (refer section 5 of this manual). On initial start-up of the modules, the counter values
will be zeroed. If the module loses power, the 505K will save the counter values to non-
volatile memeory before shutting down - these values will be restored when power is
restored.