PCC-IV Instruction Manual (Rev. 0.1)
Page 6-5
Section 6
– Blockware Functions
Technical Reference
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NAME: AIN SINGLE USE FUNCTION: N OUTPUT TYPE: A
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No Inputs
Parameter Description Default Max Min Code Notes
_____________________________________________________________________________________________
1 OPTION BOARD (0=CPU BOARD) 0 2 0 3
2 INPUT CHANNEL 1 5 1 3 1
3 VOLTS INPUT FOR 0% OUTPUT 1.000 5.100 0.000 2 2,3
4 VOLTS INPUT FOR 100% OUTPUT 5.000 5.100 0.000 2 2,3
5 SQ ROOT? 0=NO 1=YES 0 1 0 2 4
6 FILTER SECONDS 1.0 300.0 0.0 1
7 LOW FLOW CUTOFF (0=OFF) 0.00 30.00 0.00 2
Notes:
1. The quantity of Inputs available is dependent on the type of option board installed. An error
message is displayed when writing the Blockware to the PCC-IV if sufficient Inputs are not
available.
2. The difference between Parameters 3 & 4 must be greater or equal to 0.500 Volts.
3. Reverse Input scaling is valid, i.e. 0% Output = 5.000 Volts, 100% Output = 0.000 Volts.
4. Negative Inputs (after 0% and 100% scaling) yield a 0% Output if Square Root mode is selected
F5
[RAIN] (Modbus) Remote Analog Input
When the PCC-IV Modbus communications link (Comm Link) is in "Local Mode", the Comm Link can read all Block
Outputs; however, the Comm Link is prevented from writing data to (i.e. changing) all Block Outputs, except for the
RAIN
and
RDIN
Blocks. The Comm Link is always permitted to write data to
RAIN
and
RDIN
Block Outputs.
Signal Conditioning: The value written by the Comm Link first passes through a min/max limiter, followed by a %/sec
rate limiter, and then a first order low pass digital smoothing filter. The result of the digital filter becomes the
RAIN
Block Output. By setting parameters 1-4, any of or all these signal conditioners can be turned off.
The Comm Link scaling is: (Block Output*100). That is, when Comm Link writes 5047, PCC-IV interprets the value
as 50.47%. A
RAIN
Block Output of 17.01% is reported to the Comm Link as 1701. The limiting and filtering
discussed above can cause the value written by Comm Link to be different from the
RAIN
Block Output that is read
by Comm Link.
RAIN
will not indicate an error to the Comm Link if Comm Link writes a value outside of the min/max
limits.
Timeout: The value written by Comm Link remains in effect until a new value is written, or until a Comm Link time-
out. Upon Comm Link time-out (i.e. no new message received within x sec., parameter 5),
RAIN
can either remain
at the last value or switch to the default value (parameters 6 and 7). If
RAIN
switches to the default, the signal
conditioning is applied to smooth the transition.
At power down, the Block Output is saved in the Retentive Memory area of the NVRAM. During the first scan after
CPU start-up, the
RAIN
Block Output is set to the value stored in the Retentive Memory. If Retentive Memory is
invalid, the Block Output initializes to the Default Output value upon CPU start-up.
