Detcon Model
DA-1
Data Acquisition Module
Operator’s Installation & Instruction Manual
August 1, 2002 • Document #1970 • Version 1.1
detcon inc
.
Data Aquisition Module
DATA FAULT
detcon inc.
HOUSTON, TEXAS
DA-1
MODEL NO.
Table of Contents
1.0 Description
2.0 Modbus Communications
3.0 Alarm Status per Channel
4.0 Diagnostics
5.0 Enclosure Assembly
6.0 Dimensions
7.0 Wiring Diagram
8.0 Warranty
1.0 Description
The Detcon Model DA-1 Data Acquisition Module is specifically designed for use where fire and gas sensor
devices are networked over an RS-485 communications loop using Modbus™ RTU protocol.
Although the Detcon Gas Sensors can be connected directly to the communications loop through their RS485 port, certain devices such as smoke and flame detectors provide either a dry contact or 4-20ma output.
The Detcon Model DA-1 Data Acquisition Module allows the customer to connect up to four of these
devices to the communications loop via its hard-wired inputs.
The DA-1 provides a combination of four analog or digital inputs and an RS-485 output. The DA-1 can be
provided with open contact supervision where it is configured for digital inputs. The RS-485 communication
protocol is the industry standard Modbus™ RTU. LED indicators on the front of the DA-1 indicate polling
status and whether there is an active alarm condition of any of the devices. The DA-1 is mounted in an
enclosure designed and approved for use in Class I; Div 1; Groups B, C, D environments.
2.0 Modbus™ Communications
The protocol used for the RS-485 communications is Modbus™ RTU. The information available to the host
controller includes the alarm status of any of the four channels. In addition, if the open contact supervision
capability is selected, a bit will be set in each channel’s fault register.
The network address of the DA-1 module (1-256) can be set via a bank of dip switches on the PC board.
Communications are set for 9600 baud 8bits no parity and 1 stop bit.
RS-485 addressing is in Hexidecimal format as shown below:
Detcon Model DA-1 PG.2
Device # 485 Address
11
22
33
44
55
66
77
88
99
10 A
11 B
12 C
13 D
14 E
15 F
16 10
17 11
18 12
19 13
20 14
21 15
22 16
23 17
24 18
25 19
26 1A
27 1B
28 1C
... ...
... ...
255 FF
3.0 Alarm Status per Channel
The alarm status is constantly monitored by the on-board circuitry. Digital inputs will be monitored for
either open or closed contacts and analog inputs for set point violations or under/over range. The input
setup information such as NO/NC for digital inputs, analog set points and under/over range information is
software configurable.
In addition, a NO/NC common alarm relay is available in the DA-1 if needed (see wiring diagram). This will
be energized (de-energized) in the event of an alarm condition on any of the digital inputs.
4.0 Diagnostics
The diagnostics available on the module consist of the device health and open contact (digital inputs only)
supervision. Both the device health and the open contact supervision are provided as a 10XXX register.
If the open contact supervision is provided, the customer is responsible for installing the required end-of-line
resistor. A small current is passed through the resistor to create a voltage drop that is monitored by the DA-1.
Should this voltage drop go to zero, a bit will be set for that DA-1 channel denoting the open circuit condition.
Detcon Model DA-1 PG.3
5.0 Enclosure Assembly
The DA-1 enclosure (PN976-047400-000) is CSA approved for use in Class I; Div 1, Groups B, C, D environments. The optional DA-1 wiring interface assembly (PN976-047400-000) includes 2 “T” style conduit outlet
boxes rate Class I; Group D.
6.0 Dimensions
6.1 Dimensions - Wiring Interface Assembly (PN976-047400-100)
Detcon Model DA-1 PG.4
4"
5.5"
Cover
Set
Screw
Grounding Lug
5.25"
.25" Dia.
.25" Dia.
6.5
4.5
0.5
.75"
NPT
.75"
NPT
6.25"
Mounting
Holes
1/4" Dia.
6.5
11
14
17
7.0 Wiring Diagram DA-1
All unused inputs should have a single wire connected from one of the digital source terminals to the + input
of that channel, with no signal developing resistor.
Always remove power before plugging or unplugging the device. Damage can occur to the unit if it is powered during servicing or replacement.
Detcon Model DA-1 PG.5
RS-485 from
previous device
A
B
A
B
RS-485 to
next device
A
B
A
B
1
2
3
4
RS-485Digital Source RS-485
CH1 CH2 CH3 CH4
Fault
Power
Out
Power
NO/NC
COM
24VDC to
next device
24VDC from
In
previous device
Typical
Digital
Input
Emergency Pull Station
NC
+ mA
– mA
Flame Detector
Typical
4-20mA Analog
Input
7.1 Wiring Diagram - Wiring Interface Assembly (PN976-047400-100)
When the DA-1 is integrated with its Wiring Interface Assembly it may be configured to power and interface
with Detcon 3-wire sensors, 2-wire loop powered sensors, or contact closure devices. Reference the following
3 drawings for wiring instructions. The wiring interface assembly can also be used for mixing inputs. Contact
the Detcon factory for more information on mixed input wiring instructions.
Detcon Model DA-1 PG.6
A
B
A
B
RS-485Digital Source RS-485
1
2
3
4
123
mA
Fault
Power
Out
Power
In
CH1 CH2 CH3 CH4
91011
567
4
8
mA
mA
NO/NC
COM
Interface Wiring for
3-Wire Sensors
Install “+” Jumpers and “–” Jumpers
+
J2
+
J1
12
mA
123
567
4
mA
+
J3
91011
8
mA
mA
12
mA
3-Wire Sensor
Typical
mA
–
J3
–
J1
–
J2
Detcon Model DA-1 PG.7
A
B
A
B
RS-485Digital Source RS-485
1
2
3
4
CH1 CH2 CH3 CH4
Fault
Power
Out
Power
NO/NC
COM
Interface Wiring for
In
2-Wire Sensors
Install “+” Jumpers
2-Wire Sensor
Typical
mA
123
mA
567
4
+
J2
+
J1
91011
8
mA
mA
12
mA
123
567
4
mA
J1
+
J3
91011
8
mA
mA
–
–
J2
12
mA
–
J3
7.0 Warranty
Detcon Inc., as manufacturer, warrants under intended normal use each new Model DA-1 data acquisition
module to be free from defects in material and workmanship for a period of one year from the date of shipment to the original purchaser. Should the DA-1 fail to perform in accordance with published specifications
within the warranty period, return it to Detcon, Inc., for necessary repairs or replacement. All warranties and
service policies are FOB the Detcon Inc. facility located in The Woodlands, Texas.
Detcon Model DA-1 PG.8
A
Shipping Address: 3200 A-1 Research Forest Dr., The Woodlands, Texas 7381
Mailing Address: P.O. Box 8067, The Woodlands, Texas 77387-8067
phone 888-367-4286, 281-367-4100 • fax 281-292-2860 • www.detcon.com • sales@detcon.com
B
A
B
RS-485Digital Source RS-485
1
2
3
4
CH1 CH2 CH3 CH4
Fault
Power
Out
Power
NO/NC
COM
Interface Wiring for
In
Contact Closure Devices
No Jumpers
123
mA
567
4
+
J2
+
J1
91011
8
mA
mA
12
mA
123
567
4
mA
J1
+
J3
91011
8
mA
mA
–
–
J2
12
mA
–
J3
Contact Closure Devices
Typical
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