Bosch Rexroth VT-MRMA1-1, Руководство по эксплуатации

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18/52 About this product
Bosch Rexroth AG , VT-MRMA1-1, RE 30214-B/03.2019
Table 16: Actual pressure value input
Purpose Effect Setting
Generates the internal actual
pressure value signal from
the external actual pressure
value signal of the pressure
transducer. Provision of the internal actual
pressure value signal for the
pressure switch function. Configuration of the input
with DIL switch S1 to “0.5 to
5 V differential input” or “4 to
20 mA current input“.
Zero point potentiometer
ZP
:
± 5 %
Sensitivity potentiometer
GP
: 90 % to 120 %
When the actual pressure value input is configured as ”4 to 20 mA” input and
operated in series connection with a further, separate, external current input
(PLC, etc.), the module electronics provides an offset current at terminal 1. This
has to be taken into account when the external current input is calibrated!
• Monitoring of the actual pressure value input (depending on the characteristics of
the pressure transducer electronics):
• Cable break of the actual pressure value cables connected to the input (terminals 1
and 2)
• Exchange of the actual pressure value cables
• Cable break of the positive supply cable of the pressure transducer
• Cable break of the negative supply cable (ground) of the pressure transducer
• Detection of undervoltage at terminal 2 (+xp < 0.35 V)
If one of the faults above is detected, both pressure signals A and B drop to 0 V and
the red LED ”!” on the front panel of the amplifier module lights up .
In the event of a cable break of the actual pressure value cable, the further
operation of the closed-loop valve position control is not affected.
Table 17: Pressure switch function
Purpose Effect Setting
Uses switching thresholds A
and B to monitor, whether the
actual pressure value signal is
within a window around the
pressure command value.
Actual pressure value
permitted only within the valid
range within the switching
thresholds. In the event of a
cable break or a value that
exceeds or falls below the
switching thresholds, the
closed-loop position control
function is maintained. Action
required from higher-level
control. DIL switch S2 for the
individual configuration of
the lower (A) and upper (B)
switching threshold. The actual
pressure value has to be within
this range.
Table 18: Operational states of pressure switch signals A and B:
Actual pressure value Pressure switch signal A
(terminal 13) Pressure switch signal B
(terminal 14)
No switching threshold exceeded 24 V (HIGH) 24 V (HIGH)
Value fallen below lower switching
threshold (insufficient pressure) 0 V (LOW) 24 V (HIGH)
Actual pressure value input
(13)
Pressure switch function
(14)