Helios PD2-6080/PD2-6081 Modbus
®
Scanners
Instruction Manual
10
Serial Communications
Compatibility
EIA-485
Connectors
Removable screw terminal connector
Max Distance
3,937' (1,200 m) max
Status
Indication
Separate LEDs for Power (P), Transmit
(TX), and Receive (RX)
Scanner ID
1
– 247 (Scanner Modbus address)
Baud Rate
300
– 19,200 bps
Transmit
Time Delay
Programmable 0 to 4999 ms
This is the time the scanner will wait for a
slave to respond before sending another
request on the bus. This value should be
greater than 100 ms to avoid collisions on
the bus.
Data
8 bits (1 start bit, 1 or 2 stop bits)
Parity
Even, Odd, or None with 1 or 2 stop bits
Byte-To-Byte
Timeout
0.01
– 2.54 second
Turn Around
Delay
Less than 2 ms (fixed)
Note: Refer to the Helios Scanner Modbus Register Tables
located at
Dual Process Input
Two Inputs
Two non-isolated analog inputs,
independent field selectable:
0-20 mA, 4-20 mA;
10 V (0-5, 1-5, 0-10 V)
Isolated
Transmitter
Power Supply
Terminals P+ & P-: 24 VDC
10%.
All models selectable for 24, 10, or 5 VDC
supply (Switch labeled P+/P-). 85-265 VAC
models rated @ 200 mA max, 12-24 VDC
powered models rated @ 100 mA max.
5 & 10 VDC supply rated @ 50 mA max.
Refer to
on page
PV Analog
Channel ID
Ch-A mA: Assign PV to ID 256 or
Ch-A volt: 257;
Ch-B mA: Assign PV to ID 258 or
Ch-B volt: 259
Accuracy
±0.03% of calibrated span ±1 count,
square root & programmable exponent
accuracy range: 10-100% of calibrated
span
Temperature
Drift
0.005% of calibrated span/
C max from
0 to 65
C ambient,
0.01% of calibrated span/
C max from
-40 to 0
C ambient
Input Signal
Conditioning
Linear, square root, programmable
exponent, or round horizontal tank volume
calculation
Multi-Point
Linearization
2 to 32 points for PV1 and PV2
Programmable
Exponent
User selectable from 1.0001 to 2.9999 for
open channel flow
Round
Horizontal
Tank
Diameter & Length: 999.999 inch or cm
calculates volume in gallons or liters
respectively.
Low-Flow
Cutoff
0.1 to 999,999 (0 disables cutoff function)
for PV1 and PV2. Point below at which
display always shows zero.
Calibration
Range
Input Range
Minimum Span
Input 1 & Input 2
4-20 mA
0.15 mA
10 V
0.10 V
An error message will appear if the input 1
& input 2 signals are too close together.
Input
Impedance
Voltage ranges: greater than 500 k
Current ranges: 50 - 100
(depending on
internal resettable fuse impedance)
Input
Overload
Current input protected by an internal
resettable fuse, 30 VDC max. Fuse resets
automatically after fault is removed.
HART
Transparency
The scanner can support ONLY one HART
loop on either of the inputs. A signal
isolator, such as the
two HART loops are being connected.
Under the described conditions, the
scanner does not interfere with existing
HART communications; it displays the
4-20 mA primary variable and it allows the
HART communications to pass through
without interruption. The scanner is not
affected if a HART communicator is
connected to the loop. The scanner does
not display secondary HART variables.
