Chapter Four
Configuration
man_905_2.0.doc
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905-2 module (0.5 - 8 seconds). The default value of 0.5 seconds is suitable for most applications.
In applications where a digital input may turn on and off several times slowly (for example, security
switches or float switches) a debounce time of up to 8 seconds may be configured.
The configured
debounce time has no affect on pulse inputs.
Note that the analogue debounce is not configurable for the 905-1, but is configurable in the 905-2.
Set-points
allow a remote digital output to be turned on and off depending on the value of an
analogue input. The “set-point status” internal input must be mapped to an output for this option to
have effect. When the AI is less than the Low Set-point (LSP), the set-point status will be active
(on, “1”) - when the AI is more than the High Set Point (HSP), the set-point status will be reset
(off, “0”). Note that the High Set Point (HSP) must always be higher than the Low Set Point
(LSP). For the 905-1 module, only AI1 has set-point values. For 905-2 modules, all six analogue
inputs have set-points.
Debounce time operates on the set-point status in the same way as digital inputs.
Pulse Rate Scale
is used when pulse rate is mapped to an analogue output. The pulse rate scale
configures the maximum expected pulse input frequency. This is the frequency for which the pulse
rate input indicates the maximum value (20 mA if mapped to an analogue output). On the 905-1, the
maximum value is 100 Hz. On the 105-2, the maximum value is 1000 Hz for input 1, and 100 Hz
for inputs 2-4.
Pulse input 1 on the 905-2 module can measure pulse signals up to 1000 Hz, however all pulse
outputs have a maximum rate of only 100 Hz. For pulse inputs greater than 100 Hz, a Divide-by-
10 function should be configured. The input count is then divided by 10 before transmitting. The
default is 100Hz (no divide-by-10). Where the 1000Hz option is configured, then each output
pulse means 10 pulses (or 10 counts).
Pulse Output Update
is the time which pulses are output after a PI update is received. It should
be configured to correspond to the pulse input update time for the corresponding pulse input. This
ensures that the pulse output rate matches as closely as possible the pulse input rate which it is
reflecting.
For example, if the PI update time is 1 minute, then the PO update time should also be 1 minute. If
the PI update time is changed, then the PO update time at the remote module should be also
changed. The PO will still operate if the time is not changed, however pulses may be output faster
or slower than the input pulses.
4.3.5
Programming / Downloading Configuration
Transferring configuration to the 905 Module
Once editing of the configuration is complete, the configuration must be loaded into the 905 before
the new configuration takes effect. Before proceeding, close any other programmes on the PC that
is using the communications port.
•
Connect the cable from the PC’s serial port to the 905 serial port.
•
From the Communication menu, select “Select Comms Port”