Boiler house Energy monitor
2
Technical data for the B850 series flow computers (continued)
4-20 mA analog outputs
Number of outputs
2
Output signal
4 - 20 mA passive (external current loop supply required)
Resolution
16 bit DAC
Loop resistance (R L ) range for U CC = 24 V
0 .. 600 Ω
Minimum loop power supply voltage
U CCmin = RL x 0.022 + 8
Maximum loop power supply voltage
28 Vdc/SELV
Accuracy (at T amb = +25 °C/+77 °F)
Better than ± 0.2% of FS/ °C
2.12 6
Temperature drift
Maximum ± 0.02% of FS/ °C
Galvanic isolation to Analog Inputs, RS-485/RS-422, Ethernet
250 Vac continuous; 1500 Vac for 1 minute
Binary outputs (B850-W-2)
Number of outputs
4
Type of outputs
3 pole (COM, NO, NC) electromechanical relay
Contact rating (resistive load)
3 A at 85 .. 250 Vac/30 Vdc
Maximum switching voltage
250 Vac/125 Vdc
Maximum switching power
750 VA/90 W Binary outputs (B850-P-2)
Number of outputs
4
Type of outputs
2 pole Solid State Relay
Contact rating (resistive load)
0.1 A at 24 Vac/dc (max 42 Vac 60 Vdc)/SELV
Maximum ON resistance
20 Ω
Galvanic isolation (optoisolation)
250 Vac continuous; 1500 Vac for 1 minute
RS-485/422
Transmission protocol
ASC II Modbus RTU, BACnet MSTP and GSM
Number of nodes in network
256
Maximum line length
1 200 m (depends on quality of data cable and baud rate)
Baud rate
2.4, 4.8, 9.6, 19.2, 38.4, 57.6, 115.2, 230.4 kbps
Parity control
Even, Odd, None
Frame
1 start bit, 8 data bits, parity 1 bit, 1 stop bit
Internal terminating resistor
Yes, activated with DIP switch
Maximum bus terminal voltages
-8 V … +13 V/SELV
Minimal driver differential output voltage
1.5 V (for R L = 54 W )
Minimum receiver sensitivity
200 mV
Short-circuit/thermal protection
Yes
Galvanic isolation to Analog Inputs, Analog Outputs, Ethernet
250 Vac continuous; 1500 Vac for 1 minute
Technical data for the B850 series flow computers continued on next page
TI-P408-01 EMM Issue 7
Page 6 of 9
B850 Boiler House Energy Monitor
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