Digital Output 1 (Menu 4.2) - Siemens 7ME30 Instruction Manual

min Tsdr (= minimum station delay time of responder)
In this parameter the master on the PROFIBUS sets the minimum waiting time which the SITRANS F
slave has to observe before it answers a master telegram (unit: bit time = time for 1 bit at 31.25 kbit/s =
32 ms). This parameter is read-only.
5.4.2

Digital output 1 (menu 4.2)

Function (menu 4.2.1)
In the "Pulse" and "Frequency" functions the flow is converted into a binary signal at the digital output:
In the "Pulse" function a pulse sequence corresponding with the forward net volume is issued. Each pulse
corresponds with a net volume according to the set pulse valency (menu 4.2.3). The maximum number of
pulses per time unit is reached with a flow to the extent of the upper value on the measuring scale
(menu 3.1.7.3). Higher flow values can no longer be taken into consideration correctly at the pulse output.
No pulses are issued when flow = 0.
In the "Frequency" function a constant signal with a frequency proportional to the current flow value (output
value) is issued. The frequency 0 corresponds with the lower value, the set upper frequency the upper
value of the output scale (menu 3.1.8). Flow values below the lower value are issued with the frequency 0.
Upper
frequency
Current
output frequency
Lower
value
Figure 5--2 Relationship between flow and frequency (example)
If the flow exceeds the upper value on the measuring scale, the digital output can no longer correctly issue
the required number of pulses or the frequency. It is therefore better to set the flow limit (warning or alarm
limit) to this upper value and thus signal the digital output overshoot.
SITRANS F with PROFIBUS PA
C79000-B5676-C114-03
Frequency
Current
0
flow value
(output value)
Upper
value
Instruction Manual
Flow
(output scale)
33