Westermo RM-505U-K - Manual (Page 9)

man_505U-K_1.4.doc Dec 2008
    ELPRO Technologies Pty Ltd 2008 Page 9
2.4 Inputs
2.4.1 Digital Inputs
A digital input can be an external digital input or an internal status input (setpoint status or
low voltage alarm). The 505K will accept digital inputs as voltage-free contacts, NPN
devices (such as proximity switches) or TTL signals. For TTL signals, a 0-1.5V signal will
be measured as on/active/1, and a 3.5-13V signal will be measured as off/inactive/0.
The 505K will transmit the value of the digital input whenever it changes from off to on or
from on to off. A paralysis time may be configured to prevent another transmission within
this time. The 505K will also transmit an update message if a message has not been
transmitted for that input within an “update time”.
There are two update times for each digital input - one for when the input is on, and one for
when the input is off. Each update time may be configured between 10 seconds and 5 days.
For example, a digital input may be configured to update every 1 day when the input is off,
but update every 10 minutes when the input is on. If an update time of zero (or less than 10
seconds) is selected, then no update messages will be sent.
Overview:
• Input value transmitted on input change
• Update message if the input value has not been transmitted within the configured update
time for that input (10 seconds - 7 days)
• Separate update times for on and off status for digital inputs
• After each transmission, further transmission for that input is disabled for the paralysis
time (0 – 127.5 sec).
The time response of the two digital inputs is different. DI1 has a fast response, sensing a
change within 10msec. This means that the overall “input-to-output’ response is approx 50
msec. DI2 is checked every 500msec - the maximum response time of this input could be
550 msec.
2.4.2 Pulse Inputs
Pulse inputs use the same input connection as the digital inputs. The total number of digital
and pulse inputs available is two.
Each pulse input is counted as two 16 bit registers. The first register is the pulse count, and
the second register is the count of “overflows” of the first register - these two registers
provide a 32 bit count of the pulse input. Each register can be transmitted individually. A
“sensitivity” value is configured for each pulse input (0 - 32 000). Whenever the pulse count
has increased by this value since the last transmission, the 505K will transmit the new pulse
count. In addition, an update transmission of the pulse count will be transmitted if the pulse
count has not been transmitted for the update time. If an update time of zero is selected, then
no update messages will be sent.
The maximum pulse input is:
300Hz for contact or NPN inputs (1 msec minimum on-time and off-time), or
10KHz (30 µsec minimum on-time and off-time) for TTL inputs. Up to 50KHz can be