KROHNE BM 70 A_P EN - Manual (Page 10)

Installation and operating instructions BM 70 A/P Page: 10 11/00
4.2 Ex-e current output HART
®
Function Level, distance, volume (conversion table) or reflection,
and error identification;
galvanically isolated from digital input and switching output
Current 4-20 mA; without or with error message (2 mA and 22 mA)
Accuracy/linearity 0.05 %
(rel. 20 mA; at T = 20°C, 100 Ω load impedance and nominal operating voltage)
Temperature drift < 100 ppm/K (typically 30 ppm/K)
Load impedance < 500
Ω
Effect of load impedance < 0.02 % (rel. 20 mA for R
B
= 0...500
Ω
)
Effect of power < 0.02 % (rel. 20 mA for U
B
within limits of tolerance)
Hazardous-duty version: Ex e
Note: together with switching output and digital input
Digital input (terminals 81/82):
Can be used to suspend the entire measurement procedure, i.e. measurements are "frozen" (standard
setting), or to hot start the device (reprogra mming by KROHNE Service).
Applicable voltage: 5...28 V DC
Input resistance: > 1 k
Ω
Switching output (terminals 41/42):
Can be progra mmed as a limit switch, alarm contact or error message.
The contact is open in the de-energized condition.
Operating data: max. 100 mA / 30 V DC or 30 V AC.
Internal resistance: < 20
Ω
4.3 Ex-i current output HART
®
(type of protection: Ex de [ia])
Function Level, distance, volume (conversion table) or reflection;
and error identification;
passive output (current sink)
Current 4-20 mA; without or with error message (3.6 mA / 22 mA);
4 mA constant, adjustable for HART

-Multidrop
Temperature drift < 100 ppm/K (typically 30 ppm/K)
Accuracy/linearity 0.05 %
(rel. 20 mA; at T = 20°C, 10 V supply voltage and nominal operating voltage)
Supply voltage U 8-30 V (between terminals 31 and 32)
Load impedance < (U
S
- 8V) / 22 mA (U
S
= external supply voltage)
Effect of supply voltage < 0.02 % (rel. 20 mA for U = 8...30 V)
Effect of power
< 0.02 % (rel. 20 mA for U
B
within limits of tolerance)
Note: Digital input not available.
Optional switching output (terminals 41/42):
can be progra mmed as limit switch, alarm contact or error message.
The contact is open in the de-energized condition.
Operating data: 6...30 V; I
Low
< 110 mA; U
Low
< 2V; I
High
< 900 µA (U=30V) and I
High
= 200 µA (U=8V)
Ex-i safety limits
Signal circuit in type of protection: Intrinsic Safety EEx ia IIC/IIB or EEx ib IIC/IIB
for connection to a certified intrinsically safe circuit with the following peak values:
Uo = 30 V; Ik = 250 mA
Effective inner capacitance
≈
0; effective inner inductance
≈
0