Device Functions Proline Promass 83 MODBUS RS485 7 Block OUTPUTS
Endress+Hauser 75
OUTPUT SIGNAL
MODBUS register:
Data type:
Access:
4207
3212
Integer
read/write
! Note!
Function is not available unless the FREQUENCY setting was selected in the
OPERATION MODE function (4200).
For selecting the output configuration of the frequency output.
Options:
0 = PASSIVE - POSITIVE
1 = PASSIVE - NEGATIVE
2 = ACTIVE - POSITIVE
3 = ACTIVE - NEGATIVE
Factory setting: PASSIVE - POSITIVE
Explanation
• PASSIVE = power is supplied to the frequency output by means of an external
power supply.
• ACTIVE = power is supplied to the frequency output by means of the device-
internal power supply.
Configuring the output signal level (POSITIVE or NEGATIVE) determines the
quiescent behavior (at zero flow) of the frequency output.
The internal transistor is activated as follows:
• If POSITIVE is selected, the internal transistor is activated with a positive
signal level.
• If NEGATIVE is selected, the internal transistor is activated with a negative
signal level (0 V).
! Note!
With the passive output configuration, the output signal levels of the frequency
output depend on the external circuit (see examples).
Example for passive output circuit (PASSIVE)
If PASSIVE is selected, the frequency output is configured as an open collector.
A0001225
m = Open collector
n = External power supply
! Note!
For continuous currents up to 25 mA (I
max
= 250 mA / 20 ms).
Example for output configuration PASSIVE-POSITIVE:
Output configuration with an external pull-up resistance.
In the quiescent state (at zero flow), the output signal level at the terminals is 0 V.
A0004687
m = Open collector
n = Pull-Up-Resistance
o = Transistor activation in “POSITIVE” quiescent state (at zero flow)
p = Output signal level in quiescent state (at zero flow)
(continued on next page)
Function description
OUTPUTS → PULSE/FREQUENCY OUTPUT 1 → CONFIGURATION (FREQUENCY)
1
5
8 3
7
+
-
=
U =30VDC
max
m
n
U =30VDC
max
+
U (V)
t
U (V)
t
o
p
m
n
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