Input / Output Optional Pcbs; Optional Analog Input Pcb - Honeywell HA71 Technical Manual

HA71 Digital Gas Controller

3.1 Input / Output Optional PCBs

Telephone style RJ11 connections are used to add optional 8 channel
analog and digital I/O. A screen appears briefly after power up
indicating what options are connected and for which channels. This
information is also available from the Diagnostics Mode described in
Section 4.
ANALOG ANALOG
INPUT INPUT
1-8 9-16
FOUND FOUND
Figure 3-2. Optional PCB Display

3.1.1 Optional Analog Input PCB

Many transmitters or sensors have analog output signals and the 12
bit Analog Input PCB, shown in Figure 3-3, is available to accept these.
TB1, with 24 positions, offers 3 terminals per channel for distributing
power and receiving analog inputs. These are EXC and HI / LO inputs.
TB2, with only two positions, is for connecting the power supply for
powering external transmitters. Precision 100 ohm resistors (R1-R8)
between each channel's IN LO and IN HI terminals are socketed
termination resistors for 4-20mA inputs. These may be removed if
voltage inputs are to be applied.
EXC and IN LO terminals are bussed together internally. EXC terminals
are tied directly to TB2-1 (+) and IN LO terminals are tied to TB2-2
(-). Bussing allows transmitter power to be brought into the system at
a single point (TB2) and distributed back out at each channel's EXC
/ IN LO terminals to simplify field wiring. Figure 3-3 includes typical
wiring to 2 and 3 wire 4-20mA transmitters.
JP1 determines if the 8 analog inputs are applied to channels 1-8
HA71 Technical Manual
ANALOG ANALOG ALARM2
OUTPUT OUTPUT RELAY
1-8 9-16 1-8
FOUND FOUND FOUND
ALARM2
INPUT
9-16
FOUND
PRESS NEXT KEY TO EXIT
or channels 9-16. Connecting more than 8 analog inputs requires
2 PCB's with one's JP1 set for channels 1-8 and the other set for
channels 9-16.
JP1 determines if this 8 channel
Analog Input PCB provides inputs
for CH's 1-8 or 9-16. 2 PCB
assemblies are required for 16
channels.
Socketed precision resistors R1-R8
R1
are 100 ohm terminations for 4-20mA
inputs. 0-2 VDC voltage inputs may
be accepted by removing resistor.
EXC HI
CH1/9
EXC HI
CH2/10
CH # (1-8)
EXC HI LO
+Pwr Sig
2 Wire 4-20mA
Transmitter
Figure 3-3. 8 Channel Analog Input Option 10-0158
3-3
0010-1115 ASSY# 10-0158
ST-71 ANALOG INPUT BOARD
J1
J1 & J2 are interchangable I2C
JP1
connectors used to add option
PCB assemblies to the HA71.
J2
R3 R5 R7
R2 R4 R6 R8
TB2
DC PWR
TB2 is for powering bulk power
LO EXC HI LO EXC HI LO EXC HI LO
to transmitters or other input
CH3/11 CH5/13 CH7/15
devices. EXC+ is wired internally
+EXC-
to channel "EXCs" and
EXC-to-channel "LOs".
L O EXC HI LO EXC I H LO E X C HI L O
CH4/12 CH6/14 CH8/16
ANALOG INPUTS
CH # (1-8)
EXC HI LO
Sig Com Typical 2 & 3 wire 4-20mA
+Pwr
transmitter wiring (connect
correct power, 24VDC or
3 Wire 4-20mA
other, to TB2).
Transmitter
Revision 3 (04/08)