Fema C Series, User Manual, Page: 11 / 32

FEMA ELECTRÓNICA . Series C . C40-D
11
• Measuring process signals
The instrument accepts the measure of process signals in
4/20 mA and 0/10 Vdc. The instrument provides excita -
tion voltage to power up transducers.
• Scaling
The instrument allows to scale the reading to 4 digits (9999 / -1999)
with configurable decimal point to any position. The ‘
second scaling
’
function can also be used
(see section 1.25).
• Maximum oversignal
‘Maximum oversignal’ is the maximum signal accepted by the instru -
ment. Higher signal values may cause instrument damage. Lower val -
ues are non destructive but may be out of accuracy specifications.
• Response times
The response time to a signal step is 300 mSeconds, independent of
the signal range selected.
• Terminal 5 ‘multifunction’ - ‘Vexc’ or ‘External control’
To configure the +15 Vdc excitation voltage at terminal 5, set internal
jumper ‘T’ at position 1-2
(see section 1.9).
Transducers with a con -
sumption of up to 30 mA can be powered from this terminal.
To configure the ‘EK’ external contact function at terminal 5, set inter
-
nal jumper ‘T’ at position 4-5
(see section 1.9).
See section
1.9
for a list
of available functions.
1.16 Process measures
• Start-up, connections and jumpers
For instrument start-up follow the steps listed at section
1.7
. Signal
connections are indicated at section
1.5.
Location for internal jumpers
is indicated at section
1.9.
See below a list of typical connections :
• signal 4/20 mA active
• signal 4/20 mA passive • signal 0/10 Vdc passive
signal (mA-)
+15 Vdc (mA+)
1 2 3 4 5
+Vdc
common
+15 Vdc
1 2 3 4 5
• signal 0/10 Vdc active
mA +
mA -
1 2 3 4 5
+Vdc
common
1 2 3 4 5
Ranges
of measure
Scale
by default
Scalable Jumper ‘S’
(see section 1.9)
Jumper ‘T’
(see section 1.9)
Accuracy
(% FS)
Max.
oversignal
Connection
( terminals)
Z
in
4/20 mA
passive
(needs Vexc.)
0/100.0
de 9999
a -1999
D
1-2
<0.15 % 25 mA
2 (signal)
5 (Vexc)
4.7 Ohm
active 4-5
2 (mA+)
4 (mA-)
0/10 Vdc
passive
(needs Vexc.)
A
1-2
<0.20 % 25 Vdc
2 (+Vdc)
4 (comm.)
5 (Vexc)
1 M
active 4-5
2 (+Vdc)
4 (comm.)
Table 15 - Ranges of measure for process signals
1.17 Measuring frequency
• How the instrument measures frequency
The instrument measures frequency from an AC voltage
(Vac) or AC current (Aac) signal. The instrument detects
each ‘0’ crossing of the signal, either ‘0 Vac’ or ‘0 Aac’. All
available Vac and Aac signal ranges are accepted as frequency input
signal.
• How to configure the instrument to measure frequency
To measure frequency from a Vac signal, select the internal jumpers for
the desired AC voltage range
(see section 1.9)
, connect the signal for
the selected voltage range
(see section 1.10)
, and configure the instru -
ment to measure frequency
(see section 1.29.1)
. The same applies to
measure frequency from Aac signals. See example at section below.
• Scaling
The default resolution is 0.1 Hz. The instrument allows to scale the
reading to 4 digits (9999 / -1999) with configurable decimal point
to any position. The ‘
second scaling
’ function can also be used
(see
section 1.25).
• Maximum and minimum signal
Frequency signals below 15 Hz are measured as ‘0’. Frequency sig -
nals higher than 100 Hz are out of accuracy. Signals higher than
1000 Hz will read ‘display overflow’ ‘
d.oVr
’ error.
Ranges
of measure
Scale
by default
Scalable
AC signal
(see section 1.9)
Jumper ‘T’
(see section 1.9)
Response
time
Accuracy
(% reading)
15 Hz to
100 Hz
0/100.0 from 9999
to -1999
select Vac or
Aac range
4-5 70 mSec. <0.15% of
reading
Table 16 - Ranges of measure for frequency
• Example
To measure the 50 Hz frequency from a 230 Vac
power line, select jumpers ‘GI’ for 600 Vac signal
range
(see section 1.9)
, connect signal to termi -
nals ‘1’ and ‘4’
(see section 1.10)
, and configure
‘frequency’ at the input signal configuration
menu
(see section 1.29.1).