User manual

905K Radio Telemetry Module User Manual
 ELPRO Technologies Pty Ltd 2010 Page 12
message three times, then paralysis will not stop this.
Depending on the type of input signal (digital, pulse or analog), the 905K must determine what
type of signal change is required to send a transmission:
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 905K 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 905K 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 905K 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 905K 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