Micromod Micro-DCI: 53MC5000 PLC AND PRINTER INTERFACES - Manual (Page 60)

5.8 SCALING
The minimum value from an OPTO 22 module will be interpreted by the PCS as a -819
10
or 0 and
the maximum value will be interpreted by the PCS as a 3276
10
. The range of values from -819
10
to 3276
10
is equivalent to a range from 0 to 4095
10
. The values 0 to 3276 or -819 to 3276 must be
scaled to a 0 - 100% process range. For thermocouple temperature inputs where the OPTOMUX
boards have identical probe types as specified in Figure 5-4, the final temperature is written to the
database and does not require scaling. For thermocouple temperature inputs where the OP-
TOMUX boards have mixed probe types, the full range from 0 to 100% is spanned with the values
of -819 to 3276
10
. For analog outputs, the full range from 0 to 100% is spanned with the values of
0 to 4095
10
.
Three typical examples of input scaling are as follows:
Example 1: A 1-5 V sensing device is used to measure a signal that is 0 to 200 GPM (gallons per
minute) and the input analog module is 0-5 V.
Sensor Module PCS Value Comments
5 V max. 5 V max. 3276 The PCS range 0 to 3276 is scaled with 3276/200 = 16.38.
Therefore, the PCS must be scaled with an F-TRAN
algorithm that uses 16.38 to convert from the input value
read to GPM. Every 16.38 value change at the PCS = 1
GPM flow. A PCS value of -819 = 0 V input, which means
an error condition, e.g., sensor wires were cut.
1 V min. 1 V 0
0 V min. -819
Example 2: A 1-5 V sensing device is used to measure a signal that is 0 to 200 GPM (gallons per
minute) and the input analog module is 1-5 V.
Sensor Module PCS Value Comments
5 V max. 5 V max. 3276 The PCS range 0 to 3276 is scaled with 3276/200 = 16.38.
Therefore, the PCS must be scaled with an F-TRAN
algorithm that uses 16.38 to convert from the input value
read to GPM. Every 16.38 value change at the PCS = 1
GPM flow.
1 V min. 1 V min. 0
Example 3: A 0-5 V sensing device is used to measure a signal that is 0 to 200 GPM (gallons per
minute) and the input analog module is 0-5 V.
Sensor Module PCS Value Comments
5 V max. 5 V max. 3276 The PCS range is -819 to 3276, which is equivalent to
0 to 4095. It is scaled with 4095/200 = 20.475. Therefore,
the PCS must be scaled with an F-TRAN algorithm that
uses 20.475 to convert from the input value read to GPM.
Every 20.475 value change at the PCS = 1 GPM flow.
1 V 1 V 0
0 V min. 0 V min. -819
53MC9015 53MC5000 PLC and Printer Interfaces
5-14
OPTO